1 | %$Id: topography.tex 973 2012-08-07 16:03:47Z schwenkel $ |
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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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218 | \includegraphics<1>[width=\textwidth]{topography_figures/technical_implementation_grid/technical_implementation_grid_1.png} |
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219 | \includegraphics<2>[width=\textwidth]{topography_figures/technical_implementation_grid/technical_implementation_grid_2.png} |
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220 | \includegraphics<3>[width=\textwidth]{topography_figures/technical_implementation_grid/technical_implementation_grid_3.png} |
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221 | \includegraphics<4>[width=\textwidth]{topography_figures/technical_implementation_grid/technical_implementation_grid_4.png} |
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222 | \includegraphics<5>[width=\textwidth]{topography_figures/technical_implementation_grid/technical_implementation_grid_5.png} |
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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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236 | the vertical grid, since they are interpolated.} |
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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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261 | \item{\dq 2 $\Delta$x\dq instabilities} |
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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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266 | \end{itemize} |
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267 | \end{itemize} |
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268 | \end{frame} |
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269 | |
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270 | % Folie 10 |
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271 | \begin{frame} |
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272 | \frametitle{Summary: Strengths (+) and Limitations (â)} |
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273 | \small |
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274 | \begin{itemize} |
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275 | \item[+]{Horizontal and vertical surfaces can be exactly resolved (thanks to the finite difference Cartesian model architecture)} |
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276 | \item[+]{Optimization also for scalar computer architectures} |
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277 | \item[+]{Conforms with \dq 2.5D\dq format of Digital Elevation Models (DEM)} |
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278 | \par\bigskip |
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279 | \item[-]{Obstacles must be surface-mounted} |
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280 | \item[-]{Grid boxes can only be 100\% fluid or 100\% obstacle \\ \par\smallskip |
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281 | \begin{footnotesize} Obstacle surfaces that do not match the grid are approximated by grid boxes like a step-function, which |
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282 | modifies the real obstacle size \end{footnotesize}} |
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283 | \item[-]{Overhanging structures, holes etc. are not permitted due to the \dq 2.5D\dq format} |
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284 | \end{itemize} |
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285 | \end{frame} |
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286 | |
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287 | % Folie 11 |
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288 | \begin{frame} |
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289 | \frametitle{Take a Short Break... Urban Flow Visualization} |
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290 | \begin{columns}[c] |
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291 | \column{0.42\textwidth} |
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292 | \includegraphics<1>[width=\textwidth]{topography_figures/hannover_1.png} |
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293 | \href{.html}{\includegraphics<2>[width=\textwidth]{topography_figures/hannover_2.png}} |
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294 | \column{0.58\textwidth} |
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295 | Set-up: neutral boundary layer |
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296 | \begin{itemize} |
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297 | \item{Particle = passive tracer} |
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298 | \item{Colour $\sim$ particle height} |
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299 | \item{Tail length ~ particle velocity} |
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300 | \end{itemize} |
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301 | \par\bigskip |
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302 | \begin{itemize} |
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303 | \item{Flow past office tower:} |
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304 | \begin{itemize} |
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305 | \item{initially laminar: not yet an LES} |
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306 | \item{intermittent: different episodes} |
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307 | \end{itemize} |
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308 | \item{Broad street canyon flow:} |
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309 | \begin{itemize} |
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310 | \item{channeling} |
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311 | \item{low-level upstream flow} |
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312 | \end{itemize} |
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313 | \end{itemize} |
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314 | \end{columns} |
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315 | \end{frame} |
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316 | |
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317 | % Folie 12 |
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318 | \begin{frame} |
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319 | \frametitle{Required Topography Control Parameters} |
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320 | \footnotesize |
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321 | {\tt topography =} |
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322 | \begin{itemize} |
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323 | \item{{\tt 'flat'} \hspace{3cm} no topography (default)} |
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324 | \item{{\tt 'single\_building'} \hspace{1.2cm} \textcolor{red}{generic} single building} |
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325 | \item{{\tt 'single\_street\_canyon'} \hspace{0.4cm} \textcolor{red}{generic} single quasi-2D street canyon} |
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326 | \item{{\tt 'read\_from\_file'} \hspace{1.4cm} \textcolor{blue}{rastered} ASCII file, e.g. {\tt example\_topo}} |
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327 | \item{any other string \hspace{1.8cm} processed by user subroutine user\_init\_grid} |
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328 | \end{itemize} |
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329 | {\tt topography\_grid\_convention =} |
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330 | \begin{itemize} |
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331 | \item{{\tt '\textcolor{red}{cell\_edge}'} \hspace{2.2cm} default for \textcolor{red}{generic} topography: \textcolor{red}{$\leftrightarrow$}} |
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332 | \item{{\tt '\textcolor{blue}{cell\_center}'} \hspace{1.9cm} default for \textcolor{blue}{rastered} topography: \textcolor{blue}{$\bigcirc$ $\leftrightarrow$}} |
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333 | \end{itemize} |
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334 | \includegraphics<1>[width=0.5\textwidth]{topography_figures/control_parameters_1.png} |
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335 | \includegraphics<2>[width=0.5\textwidth]{topography_figures/control_parameters_2.png} |
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336 | \includegraphics<3>[width=0.5\textwidth]{topography_figures/control_parameters_3.png} |
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337 | \includegraphics<4>[width=0.5\textwidth]{topography_figures/control_parameters_4.png} |
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338 | \end{frame} |
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339 | |
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340 | % Folie 13 |
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341 | \begin{frame} |
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342 | \frametitle{Optional Topography Control Parameters (I)} |
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343 | \small |
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344 | \textbf{Generic topography} |
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345 | \scriptsize |
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346 | \begin{itemize} |
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347 | \item{topography = {\tt 'single\_building'}} |
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348 | \begin{itemize} |
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349 | \scriptsize |
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350 | \item{building\_height = 50.0 \hspace{0.67cm} height of the building} |
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351 | \item{building\_length\_x = 50.0 \hspace{0.43cm} length of the building in x-direction} |
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352 | \item{building\_length\_y = 50.0 \hspace{0.43cm} length of the building in y-direction} |
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353 | \item{building\_wall\_left \hspace{1.4cm} (default is building centered in x-direction)} |
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354 | \item{building\_wall\_south \hspace{1.13cm} (default is building centered in y-direction)} |
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355 | \end{itemize} |
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356 | \item{topography = {\tt 'single\_street\_canyon'}} |
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357 | \begin{itemize} |
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358 | \scriptsize |
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359 | \item{canyon\_height = 50.0 \hspace{0.45cm} height of the canyon \\ |
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360 | and} |
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361 | \item{canyon\_width\_x = 50.0 \hspace{0.3cm} implies canyon axis orientation in y-direction} |
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362 | \item{canyon\_wall\_left \hspace{1.17cm} (default is canyon centered in x-direction) \\ |
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363 | or} |
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364 | \item{canyon\_width\_y = 50.0 \hspace{0.3cm} implies canyon axis orientation in x-direction} |
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365 | \item{canyon\_wall\_south \hspace{0.9cm} (default is canyon centered in y-direction)} |
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366 | \end{itemize} |
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367 | \end{itemize} |
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368 | \end{frame} |
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369 | |
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370 | % Folie 14 |
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371 | \begin{frame} |
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372 | \frametitle{Optional Topography Control Parameters (II)} |
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373 | \scriptsize |
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374 | \textbf{Rastered topography}\\ |
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375 | \begin{minipage}{0.7\textwidth} |
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376 | \begin{itemize} |
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377 | \scriptsize |
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378 | \item{{\tt topography} = 'read\_from\_file'} |
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379 | \begin{itemize} |
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380 | \footnotesize |
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381 | \item{requires an external ASCII file, e.g. {\tt example\_topo:}} |
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382 | \end{itemize} |
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383 | \end{itemize} |
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384 | \end{minipage} |
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385 | \begin{minipage}{0.2\textwidth} |
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386 | \includegraphics[width=0.5\textwidth]{topography_figures/optional_control_parameters_1.png} |
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387 | \end{minipage} |
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388 | \begin{center} |
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389 | \includegraphics[width=0.85\textwidth]{topography_figures/optional_control_parameters_2.png} |
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390 | \end{center} |
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391 | \begin{itemize} |
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392 | \item[]{} |
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393 | \begin{itemize} |
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394 | \scriptsize |
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395 | \item{layout must conform to domain size and grid size dx and dy.} |
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396 | \item{height data} |
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397 | \begin{itemize} |
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398 | \scriptsize |
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399 | \item{in m above ground (INTEGER or REAL)} |
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400 | \item{do not need to match the vertical grid} |
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401 | \end{itemize} |
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402 | \end{itemize} |
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403 | \end{itemize} |
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404 | \end{frame} |
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405 | |
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406 | % Folie 15 |
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407 | \begin{frame} |
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408 | \frametitle{Optional Topography Control Parameters (III)} |
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409 | \small |
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410 | \textbf{Rastered topography} |
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411 | \begin{itemize} |
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412 | \item{{\tt topography} = 'read\_from\_file'} |
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413 | \par\smallskip |
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414 | \begin{itemize} |
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415 | \item{\textbf{mrun}-call: \\ |
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416 | {\tt mrun ... -r 'd3\# ...'}} |
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417 | \par\medskip |
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418 | \item{{\tt .mrun.config:}} |
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419 | \end{itemize} |
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420 | \end{itemize} |
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421 | \begin{center} \includegraphics[width=0.7\textwidth]{topography_figures/optional_control_parameters_3.png} \end{center} |
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422 | \end{frame} |
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423 | |
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424 | % Folie 16 |
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425 | \begin{frame} |
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426 | \frametitle{General Control Parameters (I): Suitable Driving Methods} |
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427 | \scriptsize |
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428 | \begin{itemize} |
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429 | \item{\textbf{\dq Meteorological\dq set-up M: geostrophic wind / Coriolis force}} |
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430 | \begin{itemize} |
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431 | \scriptsize |
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432 | \item{Set {\tt omega $ \neq$ 0.0}} |
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433 | \item{Construct a non-zero profile of geostrophic wind $u_g$ and/or $v_g$ using {\tt ug\_surface}, {\tt ug\_vertical\_gradient} |
---|
434 | and {\tt ug\_vertical\_gradient\_level} and/or the respective parameter set for $v_g$} |
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435 | \end{itemize} |
---|
436 | \par\bigskip |
---|
437 | \item{\textbf{\dq Engineering\dq set-up E: direct external pressure gradient / no Coriolis force}} |
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438 | \begin{itemize} |
---|
439 | \scriptsize |
---|
440 | \item{Set {\tt omega = 0.0}} |
---|
441 | \item{Set-up E1: direct external pressure gradient that does not change with time |
---|
442 | (the bulk velocity fluctuates with time)} |
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443 | \begin{itemize} |
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444 | \scriptsize |
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445 | \item{Parameters: {\tt dp\_external}, {\tt dp\_smooth}, {\tt dp\_level\_b}, {\tt dpdxy}} |
---|
446 | \end{itemize} |
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447 | \item{Set-up E2: maintain a constant bulk velocity |
---|
448 | (the direct external pressure gradient fluctuates with time)} |
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449 | \begin{itemize} |
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450 | \scriptsize |
---|
451 | \item{Parameters: {\tt conserve\_volume\_flow}, {\tt conserve\_volume\_flow\_mode}, {\tt u\_bulk}, {\tt v\_bulk}} |
---|
452 | \end{itemize} |
---|
453 | \end{itemize} |
---|
454 | \par\bigskip |
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455 | \item{\textbf{\dq Thermal\dq set-up T: directly prescribe sensible heatflux}} |
---|
456 | \begin{itemize} |
---|
457 | \item[]{} |
---|
458 | \begin{itemize} |
---|
459 | \scriptsize |
---|
460 | \item{surface\_heatflux at ground level only} |
---|
461 | \item{wall\_heatflux(0:4) at top/left/right/South/North obstacle face} |
---|
462 | \end{itemize} |
---|
463 | \end{itemize} |
---|
464 | \end{itemize} |
---|
465 | \end{frame} |
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466 | |
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467 | % Folie 17 |
---|
468 | \begin{frame} |
---|
469 | \frametitle{General Control Parameters (II): Initialization} |
---|
470 | \scriptsize |
---|
471 | \begin{itemize} |
---|
472 | \item{\textbf{\dq Meteorological\dq set-up M }\\ |
---|
473 | Initialize a non-zero profile of geostrophic wind $u_g$ and/or $v_g$ using} |
---|
474 | \begin{itemize} |
---|
475 | \scriptsize |
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476 | \item{{\tt initializing\_actions =} \textbf{'set\_constant\_profiles' (e.g. for convective BL)}} |
---|
477 | \begin{itemize} |
---|
478 | \scriptsize |
---|
479 | \item{Parameters: {\tt ug\_surface $ \neq $ 0.0} and/or {\tt vg\_surface $\neq $ 0.0}} |
---|
480 | \end{itemize} |
---|
481 | \item{{\tt initializing\_actions =} \textbf{'set\_1d-model\_profiles' (e.g. for neutral BL)}} |
---|
482 | \begin{itemize} |
---|
483 | \scriptsize |
---|
484 | \item{1D model prerun parameters with suffix {\tt \_1d} (e.g. {\tt end\_time\_1d}, {\tt damp\_level\_1d)}} |
---|
485 | \end{itemize} |
---|
486 | \end{itemize} |
---|
487 | \par\bigskip |
---|
488 | \item{\textbf{\dq Engineering\dq set-up E} \\ |
---|
489 | Good initialization may require a priori knowlegde, e.g. from previous test runs. |
---|
490 | Here, {\tt ug\_}... and {\tt vg\_}... don't refer to geostrophic wind but to the initial wind profile.} |
---|
491 | \begin{itemize} |
---|
492 | \scriptsize |
---|
493 | \item{{\tt initializing\_actions} = \textbf{'set\_constant\_profiles'}} |
---|
494 | \begin{itemize} |
---|
495 | \scriptsize |
---|
496 | \item{Parameter set: {\tt ug\_surface}, {\tt ug\_vertical\_gradient}[{\tt \_level}] and/or the respective set for $v_g$} |
---|
497 | \end{itemize} |
---|
498 | \item{{\tt initializing\_actions} = \textbf{'set\_1d-model\_profiles'}} |
---|
499 | \item{{\tt initializing\_actions} = \textbf{'by\_user' â processed by user\_init\_3d\_model}} |
---|
500 | \end{itemize} |
---|
501 | \par\bigskip |
---|
502 | \item{\textbf{\dq Thermal\dq set-up T} \\ |
---|
503 | Any of the above may apply} |
---|
504 | \end{itemize} |
---|
505 | \end{frame} |
---|
506 | |
---|
507 | % Folie 18 |
---|
508 | \begin{frame} |
---|
509 | \frametitle{General Control Parameters (III): Boundary Conditions} |
---|
510 | \footnotesize |
---|
511 | \begin{itemize} |
---|
512 | \item{Lateral boundary conditions} |
---|
513 | \begin{itemize} |
---|
514 | \item{Cyclic / non-cyclic: cf. lecture on \dq non-cyclic boundary conditions\dq} |
---|
515 | \end{itemize} |
---|
516 | \item{Bottom boundary conditions} |
---|
517 | \begin{itemize} |
---|
518 | \item{Cf. lecture on \dq numerics and boundary conditions\dq} |
---|
519 | \end{itemize} |
---|
520 | \item{Top boundary conditions} |
---|
521 | \begin{itemize} |
---|
522 | \footnotesize |
---|
523 | \item{\textbf{Channel}: {\tt bc\_uv\_t =} \textbf{'dirichlet\_0' (no-slip)}} |
---|
524 | \item{\textbf{Open channel}: {\tt bc\_uv\_t =} \textbf{'neumann' (slip)}} |
---|
525 | \item{\textbf{\dq Constant flux\dq layer} (not yet published): {\tt bc\_uv\_t =} \textbf{'neumann' (slip)} \\ |
---|
526 | with set-up E1 where {\tt dp\_level\_b >> 0} and {\tt dp\_smooth = .T.}} |
---|
527 | \end{itemize} |
---|
528 | \end{itemize} |
---|
529 | \end{frame} |
---|
530 | |
---|
531 | % Folie 19 |
---|
532 | \begin{frame} |
---|
533 | \frametitle{General Control Parameters (IV): Pressure Solver} |
---|
534 | {\tt psolver =} |
---|
535 | \par\medskip |
---|
536 | \begin{itemize} |
---|
537 | \item{'poisfft' (FFT scheme)} |
---|
538 | \begin{itemize} |
---|
539 | \item{Good performance for urban PALM version} |
---|
540 | \item{Cannot be used with non-cyclic boundary conditions} |
---|
541 | \end{itemize} |
---|
542 | \par\bigskip |
---|
543 | \item{'multigrid' (Multigrid scheme)} |
---|
544 | \begin{itemize} |
---|
545 | \item{Performance for very large number of grid points may be better than FFT} |
---|
546 | \item{This is the only possible choice for non-cyclic boundary conditions} |
---|
547 | \end{itemize} |
---|
548 | \end{itemize} |
---|
549 | \end{frame} |
---|
550 | |
---|
551 | % Folie 20 |
---|
552 | \begin{frame} |
---|
553 | \frametitle{Data Analysis / Output â Some Considerations (I)} |
---|
554 | \scriptsize |
---|
555 | \begin{itemize} |
---|
556 | \item{How to get turbulence statistics?} |
---|
557 | \begin{itemize} |
---|
558 | \scriptsize |
---|
559 | \item{Phase averaging if a direction of homogeneity exists} |
---|
560 | \item{Temporal averaging} |
---|
561 | \item{Ensemble averaging} |
---|
562 | \end{itemize} |
---|
563 | \item{Definition of turbulent fluctuations}\\ |
---|
564 | \textbf{Spatial fluctuations:} deviation from representative instantaneous spatial average |
---|
565 | \begin{itemize} |
---|
566 | \scriptsize |
---|
567 | \item{PALM: many statistics calculated on-the-fly as time series, 1D vertical profiles} |
---|
568 | \item{Not suitable for topography unless a direction of homogeneity exists} |
---|
569 | \end{itemize} |
---|
570 | \textbf{Temporal fluctuations}: deviation from representative local temporal average |
---|
571 | \begin{itemize} |
---|
572 | \scriptsize |
---|
573 | \item{Suitable for all applications including topography} |
---|
574 | \item{Requires much hard disk space and post-processing CPU time} |
---|
575 | \item{PALM: not natively supported, but following procedure works:} |
---|
576 | \begin{itemize} |
---|
577 | \scriptsize |
---|
578 | \item{Collect time-series during the simulation (2D/3D data output or user-defined time series)} |
---|
579 | \item{Check for (quasi-)steady turbulent state and sufficient averaging time} |
---|
580 | \item{Calculate statistics by post-processing making use of the Reynolds decomposition: \\ \par\medskip |
---|
581 | $\overline{w'\theta'} = \overline{w\theta} - \overline{w} \overline{\theta} $} |
---|
582 | \end{itemize} |
---|
583 | \end{itemize} |
---|
584 | \end{itemize} |
---|
585 | \end{frame} |
---|
586 | |
---|
587 | % Folie 21 |
---|
588 | \begin{frame} |
---|
589 | \frametitle{Your Responsibility and Contribution} |
---|
590 | \footnotesize |
---|
591 | \par\medskip |
---|
592 | In most cases, a new parameter is added to PALM for one specific purpose. |
---|
593 | \par\bigskip |
---|
594 | Beyond this one purpose, each new parameter normally gives many other new feature/parameter combinations in PALM. |
---|
595 | We are unable to check all these combinations by ourselves and rely on your help! |
---|
596 | \par\bigskip |
---|
597 | For example, the combination of topography and non-cyclic lateral boundary conditions has not yet been tested |
---|
598 | because both features have originally been introduced separately for different research projects. |
---|
599 | \par\bigskip |
---|
600 | Therefore, we ask you for your responsibility and contribution: |
---|
601 | \begin{itemize} |
---|
602 | \item{Please always check your PALM setup carefully. PALM is not a black box.} |
---|
603 | \item{For example, design a simple case and test your expectation.} |
---|
604 | \item{Please report potential bugs â thank you!} |
---|
605 | \begin{itemize} |
---|
606 | \item{PALM developer team} |
---|
607 | \item{PALM user community (via trac-system)} |
---|
608 | \end{itemize} |
---|
609 | \end{itemize} |
---|
610 | \end{frame} |
---|
611 | |
---|
612 | % Folie 22 |
---|
613 | \begin{frame} |
---|
614 | \Large |
---|
615 | \begin{center} \textcolor{blue!90!black!100}{Topography - Scenario examples} \end{center} |
---|
616 | \end{frame} |
---|
617 | |
---|
618 | % Folie 23 |
---|
619 | \begin{frame} |
---|
620 | \frametitle{Set-up Scenario: Single Street Canyon (I)} |
---|
621 | \par\smallskip |
---|
622 | \textbf{Single quasi-2D street canyon in neutral open channel flow with constant bulk velocity} |
---|
623 | \par\smallskip |
---|
624 | \begin{itemize} |
---|
625 | \item{{\tt trunk/EXAMPLES/canyon/}} |
---|
626 | \begin{itemize} |
---|
627 | \item{Parameter file \hspace{2cm} {\tt example\_canyon\_p3d}} |
---|
628 | \item{Run-control file \hspace{1.78cm} {\tt example\_canyon\_rc}} |
---|
629 | \item{Some documentation \hspace{0.95cm} {\tt example\_canyon.odt}} |
---|
630 | \end{itemize} |
---|
631 | \end{itemize} |
---|
632 | \begin{center} |
---|
633 | \includegraphics[width=0.85\textwidth]{topography_figures/scenario_ssc_1.png} |
---|
634 | \end{center} |
---|
635 | \end{frame} |
---|
636 | |
---|
637 | % Folie 24 |
---|
638 | \begin{frame} |
---|
639 | \frametitle{Set-up Scenario: Single Street Canyon (II)} |
---|
640 | \textbf{The phase average makes use of homogeneity in y-direction:} \\ |
---|
641 | {\tt section\_xz = -1}, {\tt data\_output = \textbf{'u\_xz\_av'}}, {\tt 'v\_xz\_av'}, {\tt 'w\_xz\_av'} |
---|
642 | \begin{center} |
---|
643 | \includegraphics[width=0.85\textwidth]{topography_figures/scenario_ssc_2.png} |
---|
644 | \end{center} |
---|
645 | \end{frame} |
---|
646 | |
---|
647 | % Folie 25 |
---|
648 | \begin{frame} |
---|
649 | \begin{tikzpicture}[remember picture, overlay] |
---|
650 | \node [shift={(6.5 cm, 5cm)}] at (current page.south west) |
---|
651 | {% |
---|
652 | \begin{tikzpicture}[remember picture, overlay] |
---|
653 | \uncover<1>{\node at (0,-0.5) {\includegraphics[width=0.7\textwidth]{topography_figures/scenario_ssc_example_1.png}};} |
---|
654 | \uncover<2>{\node at (0,-0.5) {\includegraphics[width=0.7\textwidth]{topography_figures/scenario_ssc_example_2.png}};} |
---|
655 | \uncover<3->{\node at (0,-0.5) {\includegraphics[width=0.7\textwidth]{topography_figures/scenario_ssc_example_3.png}};} |
---|
656 | \uncover<4->{\node at (-3.5,-0.2) {\includegraphics[width=0.48\textwidth]{topography_figures/scenario_ssc_example_4.png}};} |
---|
657 | \uncover<5->{\node at (3.5,-0.2) {\includegraphics[width=0.38\textwidth]{topography_figures/scenario_ssc_example_5.png}};} |
---|
658 | \end{tikzpicture} |
---|
659 | }; |
---|
660 | \end{tikzpicture} |
---|
661 | \end{frame} |
---|
662 | |
---|
663 | % Folie 26 |
---|
664 | \begin{frame} |
---|
665 | \frametitle{Set-up Scenario: Constant Flux Layer} |
---|
666 | \small |
---|
667 | \textbf{Single surface-mounted cube in neutral open channel flow with a constant flux layer} |
---|
668 | \begin{itemize} |
---|
669 | \item{{\tt trunk/EXAMPLES/constant\_flux\_layer/}} |
---|
670 | \begin{itemize} |
---|
671 | \footnotesize |
---|
672 | \item{Parameter file \hspace{2cm} {\tt example\_constant\_flux\_layer\_p3d}} |
---|
673 | \item{Run-control file \hspace{1.79cm} {\tt example\_constant\_flux\_layer\_rc}} |
---|
674 | \item{Some documentation \hspace{1.02cm} {\tt example\_constant\_flux\_layer.odt}} |
---|
675 | \end{itemize} |
---|
676 | \end{itemize} |
---|
677 | \begin{center} |
---|
678 | \includegraphics[width=0.85\textwidth]{topography_figures/scenario_cfl.png} |
---|
679 | \end{center} |
---|
680 | \end{frame} |
---|
681 | |
---|
682 | % Folie 27 |
---|
683 | \begin{frame} |
---|
684 | \begin{tikzpicture}[remember picture, overlay] |
---|
685 | \node [shift={(6.5 cm, 5cm)}] at (current page.south west) |
---|
686 | {% |
---|
687 | \begin{tikzpicture}[remember picture, overlay] |
---|
688 | \uncover<1->{\node at (0,-0.5) {\includegraphics[width=0.7\textwidth]{topography_figures/scenario_cfl_example_1.png}};} |
---|
689 | \uncover<2->{\node at (-3.5,-0.2) {\includegraphics[width=0.45\textwidth]{topography_figures/scenario_cfl_example_2.png}};} |
---|
690 | \uncover<3->{\node at (3.5,-0.2) {\includegraphics[width=0.38\textwidth]{topography_figures/scenario_cfl_example_3.png}};} |
---|
691 | \end{tikzpicture} |
---|
692 | }; |
---|
693 | \end{tikzpicture} |
---|
694 | \end{frame} |
---|
695 | |
---|
696 | % Folie 28 |
---|
697 | \begin{frame} |
---|
698 | \frametitle{Rules of Good Practise} |
---|
699 | \small |
---|
700 | \begin{itemize} |
---|
701 | \item{If you run PALM with topography, make sure that it is really LES...} |
---|
702 | \begin{itemize} |
---|
703 | \item{''Large eddies'' are ''small'' between obstacles} |
---|
704 | \begin{itemize} |
---|
705 | \item{use fine grid length to resolve turbulence there} |
---|
706 | \end{itemize} |
---|
707 | \item{Ratio of resolved to SGS fluxes} |
---|
708 | \end{itemize} |
---|
709 | \item{Check for (quasi-)steady turbulent state and sufficient averaging time.} |
---|
710 | \begin{itemize} |
---|
711 | \item{Fluctuations of time series of E, E*, maximum velocity components etc.} |
---|
712 | \end{itemize} |
---|
713 | \item{Make sure that your PALM result is independent of numerical parameters such as domain size and grid size.} |
---|
714 | \begin{itemize} |
---|
715 | \item{Sensitivity studies} |
---|
716 | \end{itemize} |
---|
717 | \item{If you intend to do a comparison with some kind of reference data, it is essential to configure the set-up of PALM |
---|
718 | in the same way as the reference experiment.} |
---|
719 | \begin{itemize} |
---|
720 | \item{For example, if you compare PALM with wind tunnel results, you have to follow the wind tunnel set-up for setting up PALM.} |
---|
721 | \end{itemize} |
---|
722 | \end{itemize} |
---|
723 | \end{frame} |
---|
724 | |
---|
725 | \end{document} |
---|