[973] | 1 | %$Id: topography.tex 1226 2013-09-18 13:19:19Z keck $ |
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| 2 | \input{header_tmp.tex} |
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| 3 | %\input{../header_lectures.tex} |
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| 4 | |
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| 5 | \usepackage[utf8]{inputenc} |
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| 6 | \usepackage{ngerman} |
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| 7 | \usepackage{pgf} |
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| 8 | \usetheme{Dresden} |
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| 9 | \usepackage{subfigure} |
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| 10 | \usepackage{units} |
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| 11 | \usepackage{multimedia} |
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| 12 | \usepackage{hyperref} |
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| 13 | \newcommand{\event}[1]{\newcommand{\eventname}{#1}} |
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| 14 | \usepackage{xmpmulti} |
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| 15 | \usepackage{tikz} |
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| 16 | \usetikzlibrary{shapes,arrows,positioning,decorations.pathreplacing} |
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| 17 | \def\Tiny{\fontsize{4pt}{4pt}\selectfont} |
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| 18 | |
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| 19 | %---------- neue Pakete |
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| 20 | \usepackage{amsmath} |
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| 21 | \usepackage{amssymb} |
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| 22 | \usepackage{multicol} |
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| 23 | \usepackage{pdfcomment} |
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| 24 | \usepackage{xcolor} |
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| 25 | |
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| 26 | \institute{Institut fÌr Meteorologie und Klimatologie, Leibniz UniversitÀt Hannover} |
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| 27 | \date{last update: \today} |
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| 28 | \event{PALM Seminar} |
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| 29 | \setbeamertemplate{navigation symbols}{} |
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| 30 | \setbeamersize{text margin left=.5cm,text margin right=.2cm} |
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| 31 | \setbeamertemplate{footline} |
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| 32 | {% |
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| 33 | \begin{beamercolorbox}[rightskip=-0.1cm]& |
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| 34 | {\includegraphics[height=0.65cm]{imuk_logo.pdf}\hfill \includegraphics[height=0.65cm]{luh_logo.pdf}} |
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| 35 | \end{beamercolorbox} |
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| 36 | \begin{beamercolorbox}[ht=2.5ex,dp=1.125ex,% |
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| 37 | leftskip=.3cm,rightskip=0.3cm plus1fil]{title in head/foot}% |
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| 38 | {\leavevmode{\usebeamerfont{author in head/foot}\insertshortauthor} \hfill \eventname \hfill \insertframenumber \; / \inserttotalframenumber}% |
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| 39 | \end{beamercolorbox}% |
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| 40 | % \begin{beamercolorbox}[colsep=1.5pt]{lower separation line foot}% |
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| 41 | % \end{beamercolorbox} |
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| 42 | }%\logo{\includegraphics[width=0.3\textwidth]{luhimuk_logo.eps}} |
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| 43 | |
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| 44 | \title[PALM - Using Topography]{PALM - Using Topography} |
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| 45 | \author{Siegfried Raasch} |
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| 46 | |
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| 47 | % Notes: |
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| 48 | % jede subsection bekommt einen punkt im menu (vertikal ausgerichtet. |
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| 49 | % jeder frame in einer subsection bekommt einen punkt (horizontal ausgerichtet) |
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| 50 | \begin{document} |
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| 51 | % Folie 1 |
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| 52 | \begin{frame} |
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| 53 | \titlepage |
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| 54 | \end{frame} |
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| 55 | |
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| 56 | % Folie 2 |
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| 57 | \begin{frame} |
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| 58 | \frametitle{Contents â Using Topography (I)} |
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| 59 | \begin{itemize} |
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| 60 | \item{Purpose of topography in PALM} |
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| 61 | \item{Definition} |
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| 62 | \item{Realization} |
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| 63 | \begin{itemize} |
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| 64 | \item{Physical concept} |
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| 65 | \item{Technical / numerical implementation} |
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| 66 | \end{itemize} |
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| 67 | \item{Strengths and limitations} |
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| 68 | \item{Control parameters} |
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| 69 | \begin{itemize} |
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| 70 | \item{Required / optional topography parameters} |
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| 71 | \item{Topography-related general control parameters} |
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| 72 | \begin{itemize} |
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| 73 | \item{Suitable driving methods, initial and boundary conditions} |
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| 74 | \item{Pressure solver} |
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| 75 | \end{itemize} |
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| 76 | \end{itemize} |
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| 77 | \item{Data output} |
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| 78 | \end{itemize} |
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| 79 | \end{frame} |
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| 80 | |
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| 81 | % Folie 3 |
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| 82 | \begin{frame} |
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| 83 | \frametitle{Purpose of Topography} |
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| 84 | \begin{itemize} |
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| 85 | \item{Optional feature to simulate flow around/above obstacles} |
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| 86 | \par\bigskip |
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| 87 | \item{Application fields} |
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| 88 | \begin{itemize} |
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| 89 | \item{Urban meteorology, wind engineering} |
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| 90 | \item{Mesoscale meteorology} |
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| 91 | \item{Oceanography} |
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| 92 | \item{...} |
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| 93 | \end{itemize} |
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| 94 | \end{itemize} |
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| 95 | \end{frame} |
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| 96 | |
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| 97 | % Folie 4 |
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| 98 | \begin{frame} |
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| 99 | \frametitle{Definition} |
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| 100 | \begin{itemize} |
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| 101 | \item{The topography definition in PALM covers solid, impermeable, fixed flow obstacles with a volume of at least one grid box.} |
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| 102 | \par\bigskip |
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| 103 | \item{The following qualifies as topography: \textcolor{green!50!black!100}{\checkmark}} |
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| 104 | \begin{itemize} |
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| 105 | \footnotesize |
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| 106 | \item{Human-made obstacles (buildings)} |
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| 107 | \item{Natural obstacles (hills, mountains)} |
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| 108 | \end{itemize} |
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| 109 | \par\bigskip |
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| 110 | \item{The following does NOT qualify as topography: \textcolor{red}{$\times$}} |
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| 111 | \begin{itemize} |
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| 112 | \footnotesize |
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| 113 | \item{\begin{tabbing}Permeable obstacles (vegetation) $\}$ \= Parameterization options in PALM: \\ |
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| 114 | \> canopy model, local roughness length \end{tabbing} } |
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| 115 | \item{Small obstacles (signposts)} |
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| 116 | \item{Moving obstacles (vehicles)} |
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| 117 | \end{itemize} |
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| 118 | \end{itemize} |
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| 119 | \end{frame} |
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| 120 | |
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| 121 | % Folie 5 |
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| 122 | \begin{frame} |
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| 123 | \frametitle{Realization - Physical Concept} |
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| 124 | \scriptsize |
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| 125 | \begin{columns}[c] |
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| 126 | \column{0.8\textwidth} |
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| 127 | \begin{itemize} |
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| 128 | \item{Flow cannot enter topography and is forced around/above it.} |
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| 129 | \end{itemize} |
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| 130 | \column{0.2\textwidth} |
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| 131 | \end{columns} |
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| 132 | \begin{columns}[c] |
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| 133 | \column{0.6\textwidth} |
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| 134 | \begin{itemize} |
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| 135 | \item{Grid boxes are} |
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| 136 | \begin{itemize} |
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| 137 | \item{\begin{minipage}{0.1\textwidth} |
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| 138 | \includegraphics[width=0.7\textwidth]{topography_figures/physical_concept_small1.png} |
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| 139 | \end{minipage} |
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| 140 | \begin{minipage}{0.5\textwidth} \scriptsize |
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| 141 | \par\medskip |
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| 142 | 100\% free fluid, \\ |
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| 143 | \end{minipage}} |
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| 144 | \item{\begin{minipage}{0.1\textwidth} |
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| 145 | \includegraphics[width=0.7\textwidth]{topography_figures/physical_concept_small2.png} |
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| 146 | \end{minipage} |
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| 147 | \begin{minipage}{0.5\textwidth} \scriptsize |
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| 148 | 100\% fluid adjacent to an obstacle, or |
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| 149 | \end{minipage}} |
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| 150 | \item{\begin{minipage}{0.1\textwidth} |
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| 151 | \includegraphics[width=0.7\textwidth]{topography_figures/physical_concept_small3.png} |
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| 152 | \end{minipage} |
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| 153 | \begin{minipage}{0.5\textwidth} \scriptsize |
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| 154 | \par\medskip |
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| 155 | 100\% obstacle. \\ |
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| 156 | \end{minipage}} |
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| 157 | \end{itemize} |
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| 158 | \item{No-slip boundary condition} |
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| 159 | \begin{itemize} |
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| 160 | \item{\scriptsize Wall-normal velocity component is zero at obstacle surface \textbf{\textcolor{blue}{---------}}} |
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| 161 | \end{itemize} |
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| 162 | \par\bigskip |
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| 163 | \item{\begin{minipage}{0.75\textwidth} \scriptsize |
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| 164 | Local surface layer for the first grid box \\adjacent to each obstacle surface |
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| 165 | \end{minipage} |
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| 166 | \begin{minipage}{0.1\textwidth} |
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| 167 | \includegraphics[width=0.7\textwidth]{topography_figures/physical_concept_small2.png} |
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| 168 | \end{minipage}} |
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| 169 | \par\smallskip |
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| 170 | \begin{itemize} |
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| 171 | \item{\scriptsize Neutral Monin-Obukhov similarity} |
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| 172 | \end{itemize} |
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| 173 | \end{itemize} |
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| 174 | \column{0.4\textwidth} |
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| 175 | \includegraphics[width=\textwidth]{topography_figures/physical_concept.png} |
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| 176 | \end{columns} |
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| 177 | \end{frame} |
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| 178 | |
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| 179 | % Folie 6 |
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| 180 | \begin{frame} |
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| 181 | \frametitle{Realization - \\ Numerical /Technical Implementation (I)} |
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| 182 | \small |
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| 183 | \begin{columns}[c] |
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| 184 | \column{0.5\textwidth} |
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| 185 | \begin{itemize} |
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| 186 | \item{Obstacles must be surface-mounted} |
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| 187 | \item{Overhanging structures \textcolor{blue}{$\times$}, holes \textcolor{red}{$\times$} etc. are not permitted.} |
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| 188 | \begin{itemize} |
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| 189 | \footnotesize |
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| 190 | \item{This simplification allows extra performance optimization by reducing the 3D obstacle dimension to a "'2.5D"' dimension.} |
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| 191 | \item{"'2.5D"' means that each horizontal grid cell is assigned only one height level.} |
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| 192 | \item{This conforms to the "'2.5D"' format of Digital Elevation Models (DEM).} |
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| 193 | \end{itemize} |
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| 194 | \end{itemize} |
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| 195 | \column{0.4\textwidth} |
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| 196 | \par\medskip |
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| 197 | \includegraphics[width=1.1\textwidth]{topography_figures/technical_implementation.png} |
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| 198 | \end{columns} |
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| 199 | \end{frame} |
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| 200 | |
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| 201 | % Folie 7 |
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| 202 | \begin{frame} |
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| 203 | \frametitle{Realization - \\ Numerical /Technical Implementation (II)} |
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| 204 | \begin{columns}[c] |
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| 205 | \column{0.4\textwidth} |
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| 206 | \footnotesize |
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| 207 | The location of the wall-normal velocity component defines the location of the impermeable obstacle surface. \\ |
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| 208 | \par\smallskip |
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| 209 | Obstacle surfaces that do not match the grid are approximated by grid boxes like a step-function. |
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| 210 | \par\bigskip |
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| 211 | $\bullet$ scalars \\ |
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| 212 | \textcolor{red}{$\bullet$ u (staggered)} \\ |
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| 213 | \textcolor{green!40!black!100}{\textbf{+} v (staggered)} |
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| 214 | % \includegraphics[width=0.4\textwidth]{topography_figures/technical_implementation_grid/technical_implementation_grid_small1.png} \\ |
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| 215 | % \includegraphics[width=0.6\textwidth]{topography_figures/technical_implementation_grid/technical_implementation_grid_small2.png} \\ |
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| 216 | % \includegraphics[width=0.6\textwidth]{topography_figures/technical_implementation_grid/technical_implementation_grid_small3.png} |
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| 217 | \column{0.6\textwidth} |
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[1226] | 218 | \includegraphics<1|handout:0>[width=\textwidth]{topography_figures/technical_implementation_grid/technical_implementation_grid_1.png} |
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| 219 | \includegraphics<2|handout:0>[width=\textwidth]{topography_figures/technical_implementation_grid/technical_implementation_grid_2.png} |
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| 220 | \includegraphics<3|handout:0>[width=\textwidth]{topography_figures/technical_implementation_grid/technical_implementation_grid_3.png} |
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| 221 | \includegraphics<4|handout:0>[width=\textwidth]{topography_figures/technical_implementation_grid/technical_implementation_grid_4.png} |
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| 222 | \includegraphics<5|handout:1>[width=\textwidth]{topography_figures/technical_implementation_grid/technical_implementation_grid_5.png} |
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[973] | 223 | \end{columns} |
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| 224 | \end{frame} |
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| 225 | |
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| 226 | % Folie 8 |
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| 227 | \begin{frame} |
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| 228 | \frametitle{Realization - \\ Numerical / Technical Implementation (III)} |
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| 229 | \footnotesize |
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| 230 | \textbf{Rastering GIS data: \dq from GIS data to ASCII raster data\dq} |
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| 231 | \begin{itemize} |
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| 232 | \item{In order to process topography from external data sources, the data must be made available |
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| 233 | to PALM as a rastered ASCII file, e.g. example\_topo.} |
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| 234 | \item{The layout of example\_topo must conform to the computational domain size and to the grid size dx and dy.} |
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| 235 | \item{The rastered height data of example\_topo are given in m above ground and do not need to match |
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[1226] | 236 | the vertical grid, since they will be interpolated, if required.} |
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[973] | 237 | \par\bigskip |
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| 238 | \item{Software known to be able to perfom the rastering process of GIS data in vector and/or raster format to PALM raster format:} |
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| 239 | \begin{itemize} |
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| 240 | \item{ArcGIS (commercial)} |
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| 241 | \item{GRASS GIS (freeware)} |
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| 242 | \item{...? (please report to us)} |
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| 243 | \end{itemize} |
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| 244 | \end{itemize} |
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| 245 | \end{frame} |
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| 246 | |
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| 247 | % Folie 9 |
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| 248 | \begin{frame} |
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| 249 | \frametitle{Realization â \\ Numerical / Technical Implementation (IV)} |
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| 250 | \small |
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| 251 | \textbf{Potential issues} |
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| 252 | \begin{itemize} |
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| 253 | \item{Load imbalance} |
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| 254 | \begin{itemize} |
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| 255 | \item{Leads to inefficient parallelization: \dq fast\dq CPU(s) must wait for \dq slow\dq CPU(s)} |
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| 256 | \item{Occurs if the CPUs do not share the same workload} |
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| 257 | \begin{itemize} |
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| 258 | \item{E.g. if topography is significantly heterogeneous in a large volume fraction of the computational domain} |
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| 259 | \end{itemize} |
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| 260 | \end{itemize} |
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[1226] | 261 | \item{\dq 2 $\Delta$x\dq instabilities (only if Piacsek-Williams advection scheme is used)} |
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[973] | 262 | \begin{itemize} |
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| 263 | \item{Upstream of obstacle walls} |
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| 264 | \item{Due to second-order finite difference advection scheme} |
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| 265 | \item{Model remains stable throughout the simulation} |
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[1226] | 266 | \item{The default Wicker-Skamarock scheme does not show any instabilities} |
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[973] | 267 | \end{itemize} |
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| 268 | \end{itemize} |
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| 269 | \end{frame} |
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| 270 | |
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| 271 | % Folie 10 |
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| 272 | \begin{frame} |
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| 273 | \frametitle{Summary: Strengths (+) and Limitations (â)} |
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| 274 | \small |
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| 275 | \begin{itemize} |
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| 276 | \item[+]{Horizontal and vertical surfaces can be exactly resolved (thanks to the finite difference Cartesian model architecture)} |
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| 277 | \item[+]{Optimization also for scalar computer architectures} |
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| 278 | \item[+]{Conforms with \dq 2.5D\dq format of Digital Elevation Models (DEM)} |
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| 279 | \par\bigskip |
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| 280 | \item[-]{Obstacles must be surface-mounted} |
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| 281 | \item[-]{Grid boxes can only be 100\% fluid or 100\% obstacle \\ \par\smallskip |
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| 282 | \begin{footnotesize} Obstacle surfaces that do not match the grid are approximated by grid boxes like a step-function, which |
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| 283 | modifies the real obstacle size \end{footnotesize}} |
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| 284 | \item[-]{Overhanging structures, holes etc. are not permitted due to the \dq 2.5D\dq format} |
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| 285 | \end{itemize} |
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| 286 | \end{frame} |
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| 287 | |
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| 288 | % Folie 11 |
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| 289 | \begin{frame} |
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| 290 | \frametitle{Take a Short Break... Urban Flow Visualization} |
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| 291 | \begin{columns}[c] |
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| 292 | \column{0.42\textwidth} |
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| 293 | \includegraphics<1>[width=\textwidth]{topography_figures/hannover_1.png} |
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| 294 | \href{.html}{\includegraphics<2>[width=\textwidth]{topography_figures/hannover_2.png}} |
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| 295 | \column{0.58\textwidth} |
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| 296 | Set-up: neutral boundary layer |
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| 297 | \begin{itemize} |
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| 298 | \item{Particle = passive tracer} |
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| 299 | \item{Colour $\sim$ particle height} |
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| 300 | \item{Tail length ~ particle velocity} |
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| 301 | \end{itemize} |
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| 302 | \par\bigskip |
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| 303 | \begin{itemize} |
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| 304 | \item{Flow past office tower:} |
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| 305 | \begin{itemize} |
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| 306 | \item{initially laminar: not yet an LES} |
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| 307 | \item{intermittent: different episodes} |
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| 308 | \end{itemize} |
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| 309 | \item{Broad street canyon flow:} |
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| 310 | \begin{itemize} |
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| 311 | \item{channeling} |
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| 312 | \item{low-level upstream flow} |
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| 313 | \end{itemize} |
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| 314 | \end{itemize} |
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| 315 | \end{columns} |
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| 316 | \end{frame} |
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| 317 | |
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| 318 | % Folie 12 |
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| 319 | \begin{frame} |
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| 320 | \frametitle{Required Topography Control Parameters} |
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| 321 | \footnotesize |
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| 322 | {\tt topography =} |
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| 323 | \begin{itemize} |
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| 324 | \item{{\tt 'flat'} \hspace{3cm} no topography (default)} |
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| 325 | \item{{\tt 'single\_building'} \hspace{1.2cm} \textcolor{red}{generic} single building} |
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| 326 | \item{{\tt 'single\_street\_canyon'} \hspace{0.4cm} \textcolor{red}{generic} single quasi-2D street canyon} |
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| 327 | \item{{\tt 'read\_from\_file'} \hspace{1.4cm} \textcolor{blue}{rastered} ASCII file, e.g. {\tt example\_topo}} |
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| 328 | \item{any other string \hspace{1.8cm} processed by user subroutine user\_init\_grid} |
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| 329 | \end{itemize} |
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| 330 | {\tt topography\_grid\_convention =} |
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| 331 | \begin{itemize} |
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| 332 | \item{{\tt '\textcolor{red}{cell\_edge}'} \hspace{2.2cm} default for \textcolor{red}{generic} topography: \textcolor{red}{$\leftrightarrow$}} |
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| 333 | \item{{\tt '\textcolor{blue}{cell\_center}'} \hspace{1.9cm} default for \textcolor{blue}{rastered} topography: \textcolor{blue}{$\bigcirc$ $\leftrightarrow$}} |
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| 334 | \end{itemize} |
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[1226] | 335 | \includegraphics<1|handout:0>[width=0.5\textwidth]{topography_figures/control_parameters_1.png} |
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| 336 | \includegraphics<2|handout:0>[width=0.5\textwidth]{topography_figures/control_parameters_2.png} |
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| 337 | \includegraphics<3|handout:0>[width=0.5\textwidth]{topography_figures/control_parameters_3.png} |
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| 338 | \includegraphics<4|handout:1>[width=0.5\textwidth]{topography_figures/control_parameters_4.png} |
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[973] | 339 | \end{frame} |
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| 340 | |
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| 341 | % Folie 13 |
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| 342 | \begin{frame} |
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| 343 | \frametitle{Optional Topography Control Parameters (I)} |
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| 344 | \small |
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| 345 | \textbf{Generic topography} |
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| 346 | \scriptsize |
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| 347 | \begin{itemize} |
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| 348 | \item{topography = {\tt 'single\_building'}} |
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| 349 | \begin{itemize} |
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| 350 | \scriptsize |
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| 351 | \item{building\_height = 50.0 \hspace{0.67cm} height of the building} |
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| 352 | \item{building\_length\_x = 50.0 \hspace{0.43cm} length of the building in x-direction} |
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| 353 | \item{building\_length\_y = 50.0 \hspace{0.43cm} length of the building in y-direction} |
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| 354 | \item{building\_wall\_left \hspace{1.4cm} (default is building centered in x-direction)} |
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| 355 | \item{building\_wall\_south \hspace{1.13cm} (default is building centered in y-direction)} |
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| 356 | \end{itemize} |
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| 357 | \item{topography = {\tt 'single\_street\_canyon'}} |
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| 358 | \begin{itemize} |
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| 359 | \scriptsize |
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| 360 | \item{canyon\_height = 50.0 \hspace{0.45cm} height of the canyon \\ |
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| 361 | and} |
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| 362 | \item{canyon\_width\_x = 50.0 \hspace{0.3cm} implies canyon axis orientation in y-direction} |
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| 363 | \item{canyon\_wall\_left \hspace{1.17cm} (default is canyon centered in x-direction) \\ |
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| 364 | or} |
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| 365 | \item{canyon\_width\_y = 50.0 \hspace{0.3cm} implies canyon axis orientation in x-direction} |
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| 366 | \item{canyon\_wall\_south \hspace{0.9cm} (default is canyon centered in y-direction)} |
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| 367 | \end{itemize} |
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| 368 | \end{itemize} |
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| 369 | \end{frame} |
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| 370 | |
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| 371 | % Folie 14 |
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| 372 | \begin{frame} |
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| 373 | \frametitle{Optional Topography Control Parameters (II)} |
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| 374 | \scriptsize |
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| 375 | \textbf{Rastered topography}\\ |
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| 376 | \begin{minipage}{0.7\textwidth} |
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| 377 | \begin{itemize} |
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| 378 | \scriptsize |
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| 379 | \item{{\tt topography} = 'read\_from\_file'} |
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| 380 | \begin{itemize} |
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| 381 | \footnotesize |
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| 382 | \item{requires an external ASCII file, e.g. {\tt example\_topo:}} |
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| 383 | \end{itemize} |
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| 384 | \end{itemize} |
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| 385 | \end{minipage} |
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| 386 | \begin{minipage}{0.2\textwidth} |
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| 387 | \includegraphics[width=0.5\textwidth]{topography_figures/optional_control_parameters_1.png} |
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| 388 | \end{minipage} |
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| 389 | \begin{center} |
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| 390 | \includegraphics[width=0.85\textwidth]{topography_figures/optional_control_parameters_2.png} |
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| 391 | \end{center} |
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| 392 | \begin{itemize} |
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| 393 | \item[]{} |
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| 394 | \begin{itemize} |
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| 395 | \scriptsize |
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| 396 | \item{layout must conform to domain size and grid size dx and dy.} |
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| 397 | \item{height data} |
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| 398 | \begin{itemize} |
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| 399 | \scriptsize |
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| 400 | \item{in m above ground (INTEGER or REAL)} |
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| 401 | \item{do not need to match the vertical grid} |
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| 402 | \end{itemize} |
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| 403 | \end{itemize} |
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| 404 | \end{itemize} |
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| 405 | \end{frame} |
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| 406 | |
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| 407 | % Folie 15 |
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| 408 | \begin{frame} |
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| 409 | \frametitle{Optional Topography Control Parameters (III)} |
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| 410 | \small |
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| 411 | \textbf{Rastered topography} |
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| 412 | \begin{itemize} |
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| 413 | \item{{\tt topography} = 'read\_from\_file'} |
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| 414 | \par\smallskip |
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| 415 | \begin{itemize} |
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| 416 | \item{\textbf{mrun}-call: \\ |
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| 417 | {\tt mrun ... -r 'd3\# ...'}} |
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| 418 | \par\medskip |
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| 419 | \item{{\tt .mrun.config:}} |
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| 420 | \end{itemize} |
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| 421 | \end{itemize} |
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| 422 | \begin{center} \includegraphics[width=0.7\textwidth]{topography_figures/optional_control_parameters_3.png} \end{center} |
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| 423 | \end{frame} |
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| 424 | |
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| 425 | % Folie 16 |
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| 426 | \begin{frame} |
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| 427 | \frametitle{General Control Parameters (I): Suitable Driving Methods} |
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| 428 | \scriptsize |
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| 429 | \begin{itemize} |
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| 430 | \item{\textbf{\dq Meteorological\dq set-up M: geostrophic wind / Coriolis force}} |
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| 431 | \begin{itemize} |
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| 432 | \scriptsize |
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| 433 | \item{Set {\tt omega $ \neq$ 0.0}} |
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| 434 | \item{Construct a non-zero profile of geostrophic wind $u_g$ and/or $v_g$ using {\tt ug\_surface}, {\tt ug\_vertical\_gradient} |
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| 435 | and {\tt ug\_vertical\_gradient\_level} and/or the respective parameter set for $v_g$} |
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| 436 | \end{itemize} |
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| 437 | \par\bigskip |
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| 438 | \item{\textbf{\dq Engineering\dq set-up E: direct external pressure gradient / no Coriolis force}} |
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| 439 | \begin{itemize} |
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| 440 | \scriptsize |
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| 441 | \item{Set {\tt omega = 0.0}} |
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| 442 | \item{Set-up E1: direct external pressure gradient that does not change with time |
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| 443 | (the bulk velocity fluctuates with time)} |
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| 444 | \begin{itemize} |
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| 445 | \scriptsize |
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| 446 | \item{Parameters: {\tt dp\_external}, {\tt dp\_smooth}, {\tt dp\_level\_b}, {\tt dpdxy}} |
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| 447 | \end{itemize} |
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| 448 | \item{Set-up E2: maintain a constant bulk velocity |
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| 449 | (the direct external pressure gradient fluctuates with time)} |
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| 450 | \begin{itemize} |
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| 451 | \scriptsize |
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| 452 | \item{Parameters: {\tt conserve\_volume\_flow}, {\tt conserve\_volume\_flow\_mode}, {\tt u\_bulk}, {\tt v\_bulk}} |
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| 453 | \end{itemize} |
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| 454 | \end{itemize} |
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| 455 | \par\bigskip |
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| 456 | \item{\textbf{\dq Thermal\dq set-up T: directly prescribe sensible heatflux}} |
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| 457 | \begin{itemize} |
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| 458 | \item[]{} |
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| 459 | \begin{itemize} |
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| 460 | \scriptsize |
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| 461 | \item{surface\_heatflux at ground level only} |
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| 462 | \item{wall\_heatflux(0:4) at top/left/right/South/North obstacle face} |
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| 463 | \end{itemize} |
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| 464 | \end{itemize} |
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| 465 | \end{itemize} |
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| 466 | \end{frame} |
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| 467 | |
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| 468 | % Folie 17 |
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| 469 | \begin{frame} |
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| 470 | \frametitle{General Control Parameters (II): Initialization} |
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| 471 | \scriptsize |
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| 472 | \begin{itemize} |
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| 473 | \item{\textbf{\dq Meteorological\dq set-up M }\\ |
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| 474 | Initialize a non-zero profile of geostrophic wind $u_g$ and/or $v_g$ using} |
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| 475 | \begin{itemize} |
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| 476 | \scriptsize |
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| 477 | \item{{\tt initializing\_actions =} \textbf{'set\_constant\_profiles' (e.g. for convective BL)}} |
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| 478 | \begin{itemize} |
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| 479 | \scriptsize |
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| 480 | \item{Parameters: {\tt ug\_surface $ \neq $ 0.0} and/or {\tt vg\_surface $\neq $ 0.0}} |
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| 481 | \end{itemize} |
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| 482 | \item{{\tt initializing\_actions =} \textbf{'set\_1d-model\_profiles' (e.g. for neutral BL)}} |
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| 483 | \begin{itemize} |
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| 484 | \scriptsize |
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| 485 | \item{1D model prerun parameters with suffix {\tt \_1d} (e.g. {\tt end\_time\_1d}, {\tt damp\_level\_1d)}} |
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| 486 | \end{itemize} |
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| 487 | \end{itemize} |
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| 488 | \par\bigskip |
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| 489 | \item{\textbf{\dq Engineering\dq set-up E} \\ |
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| 490 | Good initialization may require a priori knowlegde, e.g. from previous test runs. |
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| 491 | Here, {\tt ug\_}... and {\tt vg\_}... don't refer to geostrophic wind but to the initial wind profile.} |
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| 492 | \begin{itemize} |
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| 493 | \scriptsize |
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| 494 | \item{{\tt initializing\_actions} = \textbf{'set\_constant\_profiles'}} |
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| 495 | \begin{itemize} |
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| 496 | \scriptsize |
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| 497 | \item{Parameter set: {\tt ug\_surface}, {\tt ug\_vertical\_gradient}[{\tt \_level}] and/or the respective set for $v_g$} |
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| 498 | \end{itemize} |
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| 499 | \item{{\tt initializing\_actions} = \textbf{'set\_1d-model\_profiles'}} |
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| 500 | \item{{\tt initializing\_actions} = \textbf{'by\_user' â processed by user\_init\_3d\_model}} |
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| 501 | \end{itemize} |
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| 502 | \par\bigskip |
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| 503 | \item{\textbf{\dq Thermal\dq set-up T} \\ |
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| 504 | Any of the above may apply} |
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| 505 | \end{itemize} |
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| 506 | \end{frame} |
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| 507 | |
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| 508 | % Folie 18 |
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| 509 | \begin{frame} |
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| 510 | \frametitle{General Control Parameters (III): Boundary Conditions} |
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| 511 | \footnotesize |
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| 512 | \begin{itemize} |
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| 513 | \item{Lateral boundary conditions} |
---|
| 514 | \begin{itemize} |
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| 515 | \item{Cyclic / non-cyclic: cf. lecture on \dq non-cyclic boundary conditions\dq} |
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| 516 | \end{itemize} |
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| 517 | \item{Bottom boundary conditions} |
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| 518 | \begin{itemize} |
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| 519 | \item{Cf. lecture on \dq numerics and boundary conditions\dq} |
---|
| 520 | \end{itemize} |
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| 521 | \item{Top boundary conditions} |
---|
| 522 | \begin{itemize} |
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| 523 | \footnotesize |
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| 524 | \item{\textbf{Channel}: {\tt bc\_uv\_t =} \textbf{'dirichlet\_0' (no-slip)}} |
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| 525 | \item{\textbf{Open channel}: {\tt bc\_uv\_t =} \textbf{'neumann' (slip)}} |
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| 526 | \item{\textbf{\dq Constant flux\dq layer} (not yet published): {\tt bc\_uv\_t =} \textbf{'neumann' (slip)} \\ |
---|
| 527 | with set-up E1 where {\tt dp\_level\_b >> 0} and {\tt dp\_smooth = .T.}} |
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| 528 | \end{itemize} |
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| 529 | \end{itemize} |
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| 530 | \end{frame} |
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| 531 | |
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| 532 | % Folie 19 |
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| 533 | \begin{frame} |
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| 534 | \frametitle{General Control Parameters (IV): Pressure Solver} |
---|
| 535 | {\tt psolver =} |
---|
| 536 | \par\medskip |
---|
| 537 | \begin{itemize} |
---|
| 538 | \item{'poisfft' (FFT scheme)} |
---|
| 539 | \begin{itemize} |
---|
| 540 | \item{Good performance for urban PALM version} |
---|
| 541 | \item{Cannot be used with non-cyclic boundary conditions} |
---|
| 542 | \end{itemize} |
---|
| 543 | \par\bigskip |
---|
| 544 | \item{'multigrid' (Multigrid scheme)} |
---|
| 545 | \begin{itemize} |
---|
| 546 | \item{Performance for very large number of grid points may be better than FFT} |
---|
| 547 | \item{This is the only possible choice for non-cyclic boundary conditions} |
---|
| 548 | \end{itemize} |
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| 549 | \end{itemize} |
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| 550 | \end{frame} |
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| 551 | |
---|
| 552 | % Folie 20 |
---|
| 553 | \begin{frame} |
---|
| 554 | \frametitle{Data Analysis / Output â Some Considerations (I)} |
---|
| 555 | \scriptsize |
---|
| 556 | \begin{itemize} |
---|
| 557 | \item{How to get turbulence statistics?} |
---|
| 558 | \begin{itemize} |
---|
| 559 | \scriptsize |
---|
| 560 | \item{Phase averaging if a direction of homogeneity exists} |
---|
| 561 | \item{Temporal averaging} |
---|
| 562 | \item{Ensemble averaging} |
---|
| 563 | \end{itemize} |
---|
| 564 | \item{Definition of turbulent fluctuations}\\ |
---|
| 565 | \textbf{Spatial fluctuations:} deviation from representative instantaneous spatial average |
---|
| 566 | \begin{itemize} |
---|
| 567 | \scriptsize |
---|
| 568 | \item{PALM: many statistics calculated on-the-fly as time series, 1D vertical profiles} |
---|
| 569 | \item{Not suitable for topography unless a direction of homogeneity exists} |
---|
| 570 | \end{itemize} |
---|
| 571 | \textbf{Temporal fluctuations}: deviation from representative local temporal average |
---|
| 572 | \begin{itemize} |
---|
| 573 | \scriptsize |
---|
| 574 | \item{Suitable for all applications including topography} |
---|
| 575 | \item{Requires much hard disk space and post-processing CPU time} |
---|
| 576 | \item{PALM: not natively supported, but following procedure works:} |
---|
| 577 | \begin{itemize} |
---|
| 578 | \scriptsize |
---|
| 579 | \item{Collect time-series during the simulation (2D/3D data output or user-defined time series)} |
---|
| 580 | \item{Check for (quasi-)steady turbulent state and sufficient averaging time} |
---|
| 581 | \item{Calculate statistics by post-processing making use of the Reynolds decomposition: \\ \par\medskip |
---|
| 582 | $\overline{w'\theta'} = \overline{w\theta} - \overline{w} \overline{\theta} $} |
---|
| 583 | \end{itemize} |
---|
| 584 | \end{itemize} |
---|
| 585 | \end{itemize} |
---|
| 586 | \end{frame} |
---|
| 587 | |
---|
| 588 | % Folie 21 |
---|
| 589 | \begin{frame} |
---|
| 590 | \frametitle{Your Responsibility and Contribution} |
---|
| 591 | \footnotesize |
---|
| 592 | \par\medskip |
---|
| 593 | In most cases, a new parameter is added to PALM for one specific purpose. |
---|
| 594 | \par\bigskip |
---|
| 595 | Beyond this one purpose, each new parameter normally gives many other new feature/parameter combinations in PALM. |
---|
| 596 | We are unable to check all these combinations by ourselves and rely on your help! |
---|
| 597 | \par\bigskip |
---|
[1226] | 598 | % For example, the combination of topography and non-cyclic lateral boundary conditions has not yet been tested |
---|
| 599 | % because both features have originally been introduced separately for different research projects. |
---|
| 600 | % \par\bigskip |
---|
[973] | 601 | Therefore, we ask you for your responsibility and contribution: |
---|
| 602 | \begin{itemize} |
---|
| 603 | \item{Please always check your PALM setup carefully. PALM is not a black box.} |
---|
| 604 | \item{For example, design a simple case and test your expectation.} |
---|
| 605 | \item{Please report potential bugs â thank you!} |
---|
| 606 | \begin{itemize} |
---|
| 607 | \item{PALM developer team} |
---|
| 608 | \item{PALM user community (via trac-system)} |
---|
| 609 | \end{itemize} |
---|
| 610 | \end{itemize} |
---|
| 611 | \end{frame} |
---|
| 612 | |
---|
| 613 | % Folie 22 |
---|
| 614 | \begin{frame} |
---|
| 615 | \Large |
---|
| 616 | \begin{center} \textcolor{blue!90!black!100}{Topography - Scenario examples} \end{center} |
---|
| 617 | \end{frame} |
---|
| 618 | |
---|
| 619 | % Folie 23 |
---|
| 620 | \begin{frame} |
---|
| 621 | \frametitle{Set-up Scenario: Single Street Canyon (I)} |
---|
| 622 | \par\smallskip |
---|
| 623 | \textbf{Single quasi-2D street canyon in neutral open channel flow with constant bulk velocity} |
---|
| 624 | \par\smallskip |
---|
| 625 | \begin{itemize} |
---|
| 626 | \item{{\tt trunk/EXAMPLES/canyon/}} |
---|
| 627 | \begin{itemize} |
---|
| 628 | \item{Parameter file \hspace{2cm} {\tt example\_canyon\_p3d}} |
---|
| 629 | \item{Run-control file \hspace{1.78cm} {\tt example\_canyon\_rc}} |
---|
| 630 | \item{Some documentation \hspace{0.95cm} {\tt example\_canyon.odt}} |
---|
| 631 | \end{itemize} |
---|
| 632 | \end{itemize} |
---|
| 633 | \begin{center} |
---|
| 634 | \includegraphics[width=0.85\textwidth]{topography_figures/scenario_ssc_1.png} |
---|
| 635 | \end{center} |
---|
| 636 | \end{frame} |
---|
| 637 | |
---|
| 638 | % Folie 24 |
---|
| 639 | \begin{frame} |
---|
| 640 | \frametitle{Set-up Scenario: Single Street Canyon (II)} |
---|
| 641 | \textbf{The phase average makes use of homogeneity in y-direction:} \\ |
---|
| 642 | {\tt section\_xz = -1}, {\tt data\_output = \textbf{'u\_xz\_av'}}, {\tt 'v\_xz\_av'}, {\tt 'w\_xz\_av'} |
---|
| 643 | \begin{center} |
---|
| 644 | \includegraphics[width=0.85\textwidth]{topography_figures/scenario_ssc_2.png} |
---|
| 645 | \end{center} |
---|
| 646 | \end{frame} |
---|
| 647 | |
---|
| 648 | % Folie 25 |
---|
| 649 | \begin{frame} |
---|
| 650 | \begin{tikzpicture}[remember picture, overlay] |
---|
| 651 | \node [shift={(6.5 cm, 5cm)}] at (current page.south west) |
---|
| 652 | {% |
---|
| 653 | \begin{tikzpicture}[remember picture, overlay] |
---|
| 654 | \uncover<1>{\node at (0,-0.5) {\includegraphics[width=0.7\textwidth]{topography_figures/scenario_ssc_example_1.png}};} |
---|
| 655 | \uncover<2>{\node at (0,-0.5) {\includegraphics[width=0.7\textwidth]{topography_figures/scenario_ssc_example_2.png}};} |
---|
| 656 | \uncover<3->{\node at (0,-0.5) {\includegraphics[width=0.7\textwidth]{topography_figures/scenario_ssc_example_3.png}};} |
---|
| 657 | \uncover<4->{\node at (-3.5,-0.2) {\includegraphics[width=0.48\textwidth]{topography_figures/scenario_ssc_example_4.png}};} |
---|
| 658 | \uncover<5->{\node at (3.5,-0.2) {\includegraphics[width=0.38\textwidth]{topography_figures/scenario_ssc_example_5.png}};} |
---|
| 659 | \end{tikzpicture} |
---|
| 660 | }; |
---|
| 661 | \end{tikzpicture} |
---|
| 662 | \end{frame} |
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| 663 | |
---|
| 664 | % Folie 26 |
---|
| 665 | \begin{frame} |
---|
| 666 | \frametitle{Set-up Scenario: Constant Flux Layer} |
---|
| 667 | \small |
---|
| 668 | \textbf{Single surface-mounted cube in neutral open channel flow with a constant flux layer} |
---|
| 669 | \begin{itemize} |
---|
| 670 | \item{{\tt trunk/EXAMPLES/constant\_flux\_layer/}} |
---|
| 671 | \begin{itemize} |
---|
| 672 | \footnotesize |
---|
| 673 | \item{Parameter file \hspace{2cm} {\tt example\_constant\_flux\_layer\_p3d}} |
---|
| 674 | \item{Run-control file \hspace{1.79cm} {\tt example\_constant\_flux\_layer\_rc}} |
---|
| 675 | \item{Some documentation \hspace{1.02cm} {\tt example\_constant\_flux\_layer.odt}} |
---|
| 676 | \end{itemize} |
---|
| 677 | \end{itemize} |
---|
| 678 | \begin{center} |
---|
| 679 | \includegraphics[width=0.85\textwidth]{topography_figures/scenario_cfl.png} |
---|
| 680 | \end{center} |
---|
| 681 | \end{frame} |
---|
| 682 | |
---|
| 683 | % Folie 27 |
---|
| 684 | \begin{frame} |
---|
| 685 | \begin{tikzpicture}[remember picture, overlay] |
---|
| 686 | \node [shift={(6.5 cm, 5cm)}] at (current page.south west) |
---|
| 687 | {% |
---|
| 688 | \begin{tikzpicture}[remember picture, overlay] |
---|
| 689 | \uncover<1->{\node at (0,-0.5) {\includegraphics[width=0.7\textwidth]{topography_figures/scenario_cfl_example_1.png}};} |
---|
| 690 | \uncover<2->{\node at (-3.5,-0.2) {\includegraphics[width=0.45\textwidth]{topography_figures/scenario_cfl_example_2.png}};} |
---|
| 691 | \uncover<3->{\node at (3.5,-0.2) {\includegraphics[width=0.38\textwidth]{topography_figures/scenario_cfl_example_3.png}};} |
---|
| 692 | \end{tikzpicture} |
---|
| 693 | }; |
---|
| 694 | \end{tikzpicture} |
---|
| 695 | \end{frame} |
---|
| 696 | |
---|
| 697 | % Folie 28 |
---|
| 698 | \begin{frame} |
---|
| 699 | \frametitle{Rules of Good Practise} |
---|
| 700 | \small |
---|
| 701 | \begin{itemize} |
---|
| 702 | \item{If you run PALM with topography, make sure that it is really LES...} |
---|
| 703 | \begin{itemize} |
---|
| 704 | \item{''Large eddies'' are ''small'' between obstacles} |
---|
| 705 | \begin{itemize} |
---|
| 706 | \item{use fine grid length to resolve turbulence there} |
---|
| 707 | \end{itemize} |
---|
| 708 | \item{Ratio of resolved to SGS fluxes} |
---|
| 709 | \end{itemize} |
---|
| 710 | \item{Check for (quasi-)steady turbulent state and sufficient averaging time.} |
---|
| 711 | \begin{itemize} |
---|
| 712 | \item{Fluctuations of time series of E, E*, maximum velocity components etc.} |
---|
| 713 | \end{itemize} |
---|
| 714 | \item{Make sure that your PALM result is independent of numerical parameters such as domain size and grid size.} |
---|
| 715 | \begin{itemize} |
---|
| 716 | \item{Sensitivity studies} |
---|
| 717 | \end{itemize} |
---|
| 718 | \item{If you intend to do a comparison with some kind of reference data, it is essential to configure the set-up of PALM |
---|
| 719 | in the same way as the reference experiment.} |
---|
| 720 | \begin{itemize} |
---|
| 721 | \item{For example, if you compare PALM with wind tunnel results, you have to follow the wind tunnel set-up for setting up PALM.} |
---|
| 722 | \end{itemize} |
---|
| 723 | \end{itemize} |
---|
| 724 | \end{frame} |
---|
| 725 | |
---|
| 726 | \end{document} |
---|