source: palm/tags/release-4.0/TUTORIAL/SOURCE/topography.tex @ 4097

Last change on this file since 4097 was 1515, checked in by boeske, 9 years ago

several updates in the tutorial

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1%$Id: topography.tex 1515 2015-01-02 11:35:51Z suehring $
2\input{header_tmp.tex}
3%\input{../header_lectures.tex}
4
5\usepackage[utf8]{inputenc}
6\usepackage{ngerman}
7\usepackage{pgf}
8\usepackage{subfigure}
9\usepackage{units}
10\usepackage{multimedia}
11\usepackage{hyperref}
12\newcommand{\event}[1]{\newcommand{\eventname}{#1}}
13\usepackage{xmpmulti}
14\usepackage{tikz}
15\usetikzlibrary{shapes,arrows,positioning,decorations.pathreplacing}
16\def\Tiny{\fontsize{4pt}{4pt}\selectfont}
17
18%---------- neue Pakete
19\usepackage{amsmath}
20\usepackage{amssymb}
21\usepackage{multicol}
22\usepackage{pdfcomment}
23\usepackage{xcolor}
24
25\institute{Institute of Meteorology and Climatology, Leibniz UniversitÀt Hannover}
26\selectlanguage{english}
27\date{last update: \today}
28\event{PALM Seminar}
29\setbeamertemplate{navigation symbols}{}
30\setbeamersize{text margin left=.5cm,text margin right=.2cm}
31\setbeamertemplate{footline}
32  {%
33    \begin{beamercolorbox}[rightskip=-0.1cm]&
34     {\includegraphics[height=0.65cm]{imuk_logo.pdf}\hfill \includegraphics[height=0.65cm]{luh_logo.pdf}}
35    \end{beamercolorbox}
36    \begin{beamercolorbox}[ht=2.5ex,dp=1.125ex,%
37      leftskip=.3cm,rightskip=0.3cm plus1fil]{title in head/foot}%
38      {\leavevmode{\usebeamerfont{author in head/foot}\insertshortauthor} \hfill \eventname \hfill \insertframenumber \; / \inserttotalframenumber}%
39    \end{beamercolorbox}%
40%    \begin{beamercolorbox}[colsep=1.5pt]{lower separation line foot}%
41%    \end{beamercolorbox}
42  }%\logo{\includegraphics[width=0.3\textwidth]{luhimuk_logo.eps}}
43
44\title[PALM - Using Topography]{PALM - Using Topography}
45\author{PALM group}
46
47% Notes:
48% jede subsection bekommt einen punkt im menu (vertikal ausgerichtet.
49% jeder frame in einer subsection bekommt einen punkt (horizontal ausgerichtet)
50\begin{document}
51% Folie 1
52\begin{frame}
53\titlepage
54\end{frame}
55
56\section{Topography}
57\subsection{Topography}
58
59% Folie 2
60\begin{frame}
61   \frametitle{Contents – Using Topography (I)}
62   \begin{itemize}
63      \item{Purpose of topography in PALM} 
64      \item{Definition}
65      \item{Realization}
66      \begin{itemize}
67         \item{Physical concept}
68         \item{Technical / numerical implementation}
69      \end{itemize}
70      \item{Strengths and limitations}
71      \item{Control parameters}
72      \begin{itemize}
73         \item{Required / optional topography parameters}
74         \item{Topography-related general control parameters}
75         \begin{itemize}
76            \item{Suitable driving methods, initial and boundary conditions}
77            \item{Pressure solver}
78         \end{itemize}
79      \end{itemize}
80      \item{Data output}
81   \end{itemize}
82\end{frame}
83
84% Folie 3
85\begin{frame}
86   \frametitle{Purpose of Topography}
87   \begin{itemize}
88      \item{Optional feature to simulate flow around/above obstacles}
89      \par\bigskip
90      \item{Application fields}
91      \begin{itemize}
92         \item{Urban meteorology, wind engineering}
93         \item{Mesoscale meteorology}
94         \item{Oceanography}
95         \item{...}
96      \end{itemize} 
97   \end{itemize}
98\end{frame}
99
100% Folie 4
101\begin{frame}
102   \frametitle{Definition}   
103   \begin{itemize}
104      \item{The topography definition in PALM covers solid, impermeable, fixed flow obstacles with a volume of at least one grid box.}
105      \par\bigskip
106      \item{The following qualifies as topography: \textcolor{green!50!black!100}{\checkmark}}     
107      \begin{itemize}
108         \footnotesize
109         \item{Human-made obstacles (buildings)}
110         \item{Natural obstacles (hills, mountains)}
111      \end{itemize}
112      \par\bigskip
113      \item{The following does NOT qualify as topography: \textcolor{red}{$\times$}}
114      \begin{itemize}
115         \footnotesize
116         \item{\begin{tabbing}Permeable obstacles (vegetation) $\}$  \= Parameterization options in PALM: \\
117                                                                     \> canopy model, local roughness length  \end{tabbing} } 
118         \item{Small obstacles (signposts)}
119         \item{Moving obstacles (vehicles)}                                                   
120      \end{itemize}
121   \end{itemize}
122\end{frame}
123
124% Folie 5
125\begin{frame}
126   \frametitle{Realization - Physical Concept}
127   \scriptsize
128   \begin{columns}[c]
129   \column{0.8\textwidth}
130      \begin{itemize}
131         \item{Flow cannot enter topography and is forced around/above it.}
132      \end{itemize}
133   \column{0.2\textwidth}
134   \end{columns}
135   \begin{columns}[c]
136   \column{0.6\textwidth}
137      \begin{itemize}
138         \item{Grid boxes are}
139         \begin{itemize}
140            \item{\begin{minipage}{0.1\textwidth} 
141                     \includegraphics[width=0.7\textwidth]{topography_figures/physical_concept_small1.png}
142                  \end{minipage}
143                  \begin{minipage}{0.5\textwidth} \scriptsize
144                     \par\medskip
145                     100\% free fluid, \\
146                  \end{minipage}}
147            \item{\begin{minipage}{0.1\textwidth}
148                     \includegraphics[width=0.7\textwidth]{topography_figures/physical_concept_small2.png}
149                  \end{minipage}
150                  \begin{minipage}{0.5\textwidth} \scriptsize
151                     100\% fluid adjacent to an obstacle, or
152                  \end{minipage}}     
153            \item{\begin{minipage}{0.1\textwidth} 
154                     \includegraphics[width=0.7\textwidth]{topography_figures/physical_concept_small3.png}
155                  \end{minipage}
156                  \begin{minipage}{0.5\textwidth} \scriptsize
157                     \par\medskip
158                     100\% obstacle. \\
159                  \end{minipage}}             
160         \end{itemize}
161         \item{No-slip boundary condition}
162         \begin{itemize}
163            \item{\scriptsize Wall-normal velocity component is zero at obstacle surface \textbf{\textcolor{blue}{---------}}}
164         \end{itemize}
165         \par\bigskip
166         \item{\begin{minipage}{0.75\textwidth}  \scriptsize
167                  Local surface layer for the first grid box \\adjacent to each obstacle surface
168               \end{minipage}
169               \begin{minipage}{0.1\textwidth}
170                  \includegraphics[width=0.7\textwidth]{topography_figures/physical_concept_small2.png}
171               \end{minipage}}
172         \par\smallskip
173         \begin{itemize}
174            \item{\scriptsize Neutral Monin-Obukhov similarity}
175         \end{itemize}
176      \end{itemize}
177   \column{0.4\textwidth}
178      \includegraphics[width=\textwidth]{topography_figures/physical_concept.png}
179   \end{columns}
180\end{frame}
181
182% Folie 6
183\begin{frame}
184   \frametitle{Realization - \\ Numerical /Technical Implementation (I)}
185   \small
186   \begin{columns}[c]
187   \column{0.5\textwidth}
188      \begin{itemize}
189         \item{Obstacles must be surface-mounted}
190         \item{Overhanging structures \textcolor{blue}{$\times$}, holes \textcolor{red}{$\times$} etc. are not permitted.}
191         \begin{itemize}
192            \footnotesize
193            \item{This simplification allows extra performance optimization by reducing the 3D obstacle dimension to a "'2.5D"' dimension.}
194            \item{"'2.5D"' means that each horizontal grid cell is assigned only one height level.}
195            \item{This conforms to the "'2.5D"' format of Digital Elevation Models (DEM).}
196         \end{itemize}
197      \end{itemize}     
198   \column{0.4\textwidth}
199      \par\medskip
200      \includegraphics[width=1.1\textwidth]{topography_figures/technical_implementation.png}
201   \end{columns}
202\end{frame}
203
204% Folie 7
205\begin{frame}
206   \frametitle{Realization - \\ Numerical /Technical Implementation (II)}
207   \begin{columns}[c]
208   \column{0.4\textwidth}
209      \footnotesize     
210      The location of the wall-normal velocity component defines the location of the impermeable obstacle surface. \\
211      \par\smallskip
212      Obstacle surfaces that do not match the grid are approximated by grid boxes like a step-function.
213      \par\bigskip
214      $\bullet$ scalars \\
215      \textcolor{red}{$\bullet$ u (staggered)} \\
216      \textcolor{green!40!black!100}{\textbf{+} v (staggered)}
217%      \includegraphics[width=0.4\textwidth]{topography_figures/technical_implementation_grid/technical_implementation_grid_small1.png} \\
218%      \includegraphics[width=0.6\textwidth]{topography_figures/technical_implementation_grid/technical_implementation_grid_small2.png} \\
219%      \includegraphics[width=0.6\textwidth]{topography_figures/technical_implementation_grid/technical_implementation_grid_small3.png}
220   \column{0.6\textwidth}
221      \includegraphics<1|handout:0>[width=\textwidth]{topography_figures/technical_implementation_grid/technical_implementation_grid_1.png}
222      \includegraphics<2|handout:0>[width=\textwidth]{topography_figures/technical_implementation_grid/technical_implementation_grid_2.png}
223      \includegraphics<3|handout:0>[width=\textwidth]{topography_figures/technical_implementation_grid/technical_implementation_grid_3.png}
224      \includegraphics<4|handout:0>[width=\textwidth]{topography_figures/technical_implementation_grid/technical_implementation_grid_4.png}
225      \includegraphics<5|handout:1>[width=\textwidth]{topography_figures/technical_implementation_grid/technical_implementation_grid_5.png}
226   \end{columns}
227\end{frame}
228
229% Folie 8
230\begin{frame}
231   \frametitle{Realization - \\ Numerical / Technical Implementation (III)}
232   \footnotesize
233   \textbf{Rastering GIS data: \dq from GIS data to ASCII raster data\dq}
234   \begin{itemize}
235      \item{In order to process topography from external data sources, the data must be made available
236            to PALM as a rastered ASCII file, e.g. example\_topo.} 
237      \item{The layout of example\_topo must conform to the computational domain size and to the grid size dx and dy.}
238      \item{The rastered height data of example\_topo are given in m above ground and do not need to match
239            the vertical grid, since they will be interpolated, if required.}
240      \par\bigskip
241      \item{Software known to be able to perfom the rastering process of GIS data in vector and/or raster format to PALM raster format:}
242      \begin{itemize}
243         \item{ArcGIS (commercial)}
244         \item{GRASS GIS (freeware)}
245      \end{itemize}
246   \end{itemize}
247\end{frame}
248
249% Folie 9
250\begin{frame}
251   \frametitle{Realization – \\ Numerical / Technical Implementation (IV)} 
252   \small
253   \textbf{Potential issue}
254   \begin{itemize}
255      \item{Load imbalance} 
256      \begin{itemize}
257         \item{Leads to inefficient parallelization: \dq fast\dq CPU(s) must wait for \dq slow\dq CPU(s)}
258         \item{Occurs if the CPUs do not share the same workload}
259         \begin{itemize}
260            \item{E.g. if topography is significantly heterogeneous in a large volume fraction of the computational domain}
261         \end{itemize}
262      \end{itemize}     
263   \end{itemize}
264\end{frame}
265
266% Folie 10
267\begin{frame}
268   \frametitle{Summary: Strengths (+) and Limitations (–)}
269   \small
270   \begin{itemize}
271      \item[+]{Horizontal and vertical surfaces can be exactly resolved (thanks to the finite difference Cartesian model architecture)}
272      \item[+]{Optimization also for scalar computer architectures}
273      \item[+]{Conforms with \dq 2.5D\dq format of Digital Elevation Models (DEM)} 
274      \par\bigskip
275      \item[-]{Obstacles must be surface-mounted}
276      \item[-]{Grid boxes can only be 100\% fluid or 100\% obstacle \\ \par\smallskip
277              \begin{footnotesize} Obstacle surfaces that do not match the grid are approximated by grid boxes like a step-function, which can modify the real obstacle size or the orientation of the obstacle faces\end{footnotesize}}
278      \item[-]{Overhanging structures, holes etc. are not permitted due to the \dq 2.5D\dq format}
279   \end{itemize}
280\end{frame}
281
282% Folie 11
283\begin{frame}
284   \frametitle{Take a Short Break... Urban Flow Visualization}
285   \begin{columns}[c]
286   \column{0.42\textwidth}
287      \includegraphics<1>[width=\textwidth]{topography_figures/hannover_1.png}
288      \href{.html}{\includegraphics<2>[width=\textwidth]{topography_figures/hannover_2.png}}
289   \column{0.58\textwidth}
290      Set-up: neutral boundary layer
291      \begin{itemize}
292         \item{Particle = passive tracer}
293         \item{Colour $\sim$ particle height}
294         \item{Tail length ~ particle velocity}         
295      \end{itemize}     
296      \par\bigskip
297      \begin{itemize}
298         \item{Flow past office tower:}
299         \begin{itemize}
300            \item{initially laminar: not yet an LES}
301            \item{intermittent: different episodes}
302         \end{itemize}
303         \item{Broad street canyon flow:}
304         \begin{itemize}
305            \item{channeling}
306            \item{low-level upstream flow}
307         \end{itemize}
308      \end{itemize}
309   \end{columns}
310\end{frame}
311
312% Folie 12
313\begin{frame}
314   \frametitle{Required Topography Control Parameters}
315    \footnotesize
316   {\tt topography =} 
317   \begin{itemize}
318      \item{{\tt 'flat'} \hspace{3cm} no topography (default)}
319      \item{{\tt 'single\_building'} \hspace{1.2cm} \textcolor{red}{generic} single building} 
320      \item{{\tt 'single\_street\_canyon'} \hspace{0.4cm} \textcolor{red}{generic} single quasi-2D street canyon}
321      \item{{\tt 'read\_from\_file'} \hspace{1.4cm} \textcolor{blue}{rastered} ASCII file, e.g. {\tt example\_topo}}
322      \item{any other string \hspace{1.8cm} processed by user subroutine user\_init\_grid}
323   \end{itemize}
324   {\tt topography\_grid\_convention =}
325   \begin{itemize}
326      \item{{\tt '\textcolor{red}{cell\_edge}'} \hspace{2.2cm} default for \textcolor{red}{generic} topography: \textcolor{red}{$\leftrightarrow$}}
327      \item{{\tt '\textcolor{blue}{cell\_center}'} \hspace{1.9cm} default for \textcolor{blue}{rastered} topography: \textcolor{blue}{$\bigcirc$ $\leftrightarrow$}} 
328   \end{itemize}
329   \includegraphics<1|handout:0>[width=0.5\textwidth]{topography_figures/control_parameters_1.png}
330   \includegraphics<2|handout:0>[width=0.5\textwidth]{topography_figures/control_parameters_2.png}
331   \includegraphics<3|handout:0>[width=0.5\textwidth]{topography_figures/control_parameters_3.png}
332   \includegraphics<4|handout:1>[width=0.5\textwidth]{topography_figures/control_parameters_4.png}
333\end{frame}
334
335% Folie 13
336\begin{frame}
337   \frametitle{Optional Topography Control Parameters (I)}
338   \small
339   \textbf{Generic topography}   
340   \scriptsize
341   \begin{itemize}
342      \item{topography = {\tt 'single\_building'}} 
343      \begin{itemize}
344         \scriptsize
345         \item{building\_height = 50.0 \hspace{0.67cm} height of the building}
346         \item{building\_length\_x = 50.0 \hspace{0.43cm} length of the building in x-direction}
347         \item{building\_length\_y = 50.0 \hspace{0.43cm} length of the building in y-direction}
348         \item{building\_wall\_left \hspace{1.4cm} (default is building centered in x-direction)}
349         \item{building\_wall\_south \hspace{1.13cm} (default is building centered in y-direction)}
350      \end{itemize}
351      \item{topography = {\tt 'single\_street\_canyon'}}
352      \begin{itemize}
353         \scriptsize
354         \item{canyon\_height = 50.0 \hspace{0.45cm} height of the canyon \\
355               and}
356         \item{canyon\_width\_x = 50.0 \hspace{0.3cm} implies canyon axis orientation in y-direction}
357         \item{canyon\_wall\_left \hspace{1.17cm} (default is canyon centered in x-direction) \\
358               or}
359         \item{canyon\_width\_y = 50.0 \hspace{0.3cm} implies canyon axis orientation in x-direction}
360         \item{canyon\_wall\_south \hspace{0.9cm} (default is canyon centered in y-direction)}
361      \end{itemize}
362   \end{itemize}
363\end{frame}
364
365% Folie 14
366\begin{frame}
367   \frametitle{Optional Topography Control Parameters (II)}
368   \scriptsize   
369   \textbf{Rastered topography}\\
370   \begin{minipage}{0.7\textwidth}
371      \begin{itemize}
372         \scriptsize
373         \item{{\tt topography} = 'read\_from\_file'} 
374         \begin{itemize}
375            \footnotesize
376            \item{requires an external ASCII file, e.g. {\tt example\_topo:}}
377         \end{itemize}
378      \end{itemize}
379   \end{minipage}
380   \begin{minipage}{0.2\textwidth}
381      \includegraphics[width=0.5\textwidth]{topography_figures/optional_control_parameters_1.png}
382   \end{minipage}
383   \begin{center}
384      \includegraphics[width=0.85\textwidth]{topography_figures/optional_control_parameters_2.png}
385   \end{center}
386   \begin{itemize}
387      \item[]{}
388      \begin{itemize} 
389         \scriptsize         
390         \item{layout must conform to domain size and grid size dx and dy.}
391         \item{height data}
392         \begin{itemize}
393            \scriptsize
394            \item{in m above ground (INTEGER or REAL)}
395            \item{do not need to match the vertical grid}
396         \end{itemize}
397      \end{itemize}
398   \end{itemize}
399\end{frame}
400
401% Folie 15
402\begin{frame}
403   \frametitle{Optional Topography Control Parameters (III)}
404   \small
405   \textbf{Rastered topography}
406   \begin{itemize}
407      \item{{\tt topography} = 'read\_from\_file'}
408      \par\smallskip
409      \begin{itemize}
410         \item{\textbf{mrun}-call: \\
411               {\tt mrun ... -r 'd3\# ...'}}
412         \par\medskip
413         \item{{\tt .mrun.config:}}
414      \end{itemize}
415   \end{itemize} 
416   \begin{center} \includegraphics[width=0.7\textwidth]{topography_figures/optional_control_parameters_3.png} \end{center}
417\end{frame}
418
419% Folie 16   
420\begin{frame}
421   \frametitle{General Control Parameters (I): Suitable Driving Methods}
422   \scriptsize
423   \begin{itemize}
424      \item{\textbf{\dq Meteorological\dq set-up M: geostrophic wind / Coriolis force}}
425      \begin{itemize}
426         \scriptsize
427         \item{Set {\tt omega $ \neq$ 0.0}}
428         \item{Construct a non-zero profile of geostrophic wind $u_g$ and/or $v_g$ using {\tt ug\_surface}, {\tt ug\_vertical\_gradient}
429               and {\tt ug\_vertical\_gradient\_level} and/or the respective parameter set for $v_g$}
430      \end{itemize}
431      \par\bigskip
432      \item{\textbf{\dq Engineering\dq set-up E: direct external pressure gradient / no Coriolis force}}
433      \begin{itemize}
434         \scriptsize
435         \item{Set {\tt omega = 0.0}}
436         \item{Set-up E1: direct external pressure gradient that does not change with time
437                 (the bulk velocity fluctuates with time)}
438         \begin{itemize}
439            \scriptsize
440            \item{Parameters: {\tt dp\_external}, {\tt dp\_smooth}, {\tt dp\_level\_b}, {\tt dpdxy}}
441         \end{itemize}
442         \item{Set-up E2: maintain a constant bulk velocity
443                 (the direct external pressure gradient fluctuates with time)}
444         \begin{itemize}
445             \scriptsize
446             \item{Parameters: {\tt conserve\_volume\_flow}, {\tt conserve\_volume\_flow\_mode}, {\tt u\_bulk}, {\tt v\_bulk}}
447         \end{itemize}
448      \end{itemize}
449      \par\bigskip
450      \item{\textbf{\dq Thermal\dq set-up T: directly prescribe sensible heatflux}}
451      \begin{itemize}
452         \item[]{}
453         \begin{itemize}
454            \scriptsize
455            \item{surface\_heatflux at ground level only} 
456            \item{wall\_heatflux(0:4) at top/left/right/South/North obstacle face}
457         \end{itemize}
458      \end{itemize}
459   \end{itemize}
460\end{frame}
461
462% Folie 17
463\begin{frame}
464   \frametitle{General Control Parameters (II): Initialization}
465   \scriptsize
466   \begin{itemize}
467      \item{\textbf{\dq Meteorological\dq set-up M }\\
468            Initialize a non-zero profile of geostrophic wind $u_g$ and/or $v_g$ using}
469      \begin{itemize}
470         \scriptsize
471         \item{{\tt initializing\_actions =} \textbf{'set\_constant\_profiles' (e.g. for convective BL)}}
472         \begin{itemize}
473            \scriptsize
474            \item{Parameters: {\tt ug\_surface $ \neq $ 0.0} and/or {\tt vg\_surface $\neq $ 0.0}}
475         \end{itemize}
476         \item{{\tt initializing\_actions =} \textbf{'set\_1d-model\_profiles' (e.g. for neutral BL)}}
477         \begin{itemize}
478            \scriptsize
479            \item{1D model prerun parameters with suffix {\tt \_1d} (e.g. {\tt end\_time\_1d}, {\tt damp\_level\_1d)}}
480         \end{itemize}
481      \end{itemize} 
482      \par\bigskip
483      \item{\textbf{\dq Engineering\dq set-up E} \\
484            Good initialization may require a priori knowlegde, e.g. from previous test runs.
485            Here, {\tt ug\_}... and {\tt vg\_}... don't refer to geostrophic wind but to the initial wind profile.} 
486      \begin{itemize}
487         \scriptsize
488         \item{{\tt initializing\_actions} = \textbf{'set\_constant\_profiles'}}
489         \begin{itemize}
490            \scriptsize
491            \item{Parameter set: {\tt ug\_surface}, {\tt ug\_vertical\_gradient}[{\tt \_level}] and/or the respective set for $v_g$}
492         \end{itemize}
493         \item{{\tt initializing\_actions} = \textbf{'set\_1d-model\_profiles'}}
494         \item{{\tt initializing\_actions} = \textbf{'by\_user' – processed by user\_init\_3d\_model}}
495      \end{itemize}
496      \par\bigskip
497      \item{\textbf{\dq Thermal\dq set-up T} \\
498            Any of the above may apply}
499   \end{itemize}
500\end{frame}
501
502% Folie 18
503\begin{frame}
504   \frametitle{General Control Parameters (III): Boundary Conditions}
505   \footnotesize
506   \begin{itemize}
507      \item{Lateral boundary conditions}
508      \begin{itemize}
509         \item{Cyclic / non-cyclic: cf. lecture on \dq non-cyclic boundary conditions\dq}
510      \end{itemize} 
511      \item{Bottom boundary conditions}
512      \begin{itemize}
513         \item{Cf. lecture on \dq numerics and boundary conditions\dq}
514      \end{itemize}
515      \item{Top boundary conditions}
516      \begin{itemize}
517         \footnotesize
518         \item{\textbf{Channel}: {\tt bc\_uv\_t =} \textbf{'dirichlet\_0' (no-slip)}}
519         \item{\textbf{Open channel}: {\tt bc\_uv\_t =} \textbf{'neumann' (slip)}}
520         \item{\textbf{\dq Constant flux\dq layer}: {\tt bc\_uv\_t =} \textbf{'neumann' (slip)} \\
521                with set-up E1 where {\tt dp\_level\_b >> 0} and {\tt dp\_smooth = .T.}}
522      \end{itemize}
523   \end{itemize}
524\end{frame}
525
526% Folie 19
527\begin{frame}
528   \frametitle{General Control Parameters (IV): Pressure Solver} 
529   {\tt psolver =}
530   \par\medskip
531   \begin{itemize}
532      \item{'poisfft' (FFT scheme)} 
533      \begin{itemize}
534         \item{Good performance for urban PALM version}
535         \item{Cannot be used with non-cyclic boundary conditions}
536      \end{itemize}
537      \par\bigskip
538      \item{'multigrid' (Multigrid scheme)}
539      \begin{itemize}
540         \item{Performance for very large number of grid points may be better than FFT}
541         \item{This is the only possible choice for non-cyclic boundary conditions}
542      \end{itemize}
543   \end{itemize}
544\end{frame}
545
546% Folie 20
547\begin{frame}
548   \frametitle{Data Analysis / Output – Some Considerations (I)}
549   \scriptsize
550   \begin{itemize}
551      \item{How to get turbulence statistics?}
552      \begin{itemize}
553         \scriptsize
554         \item{Phase averaging if a direction of homogeneity exists}
555         \item{Temporal averaging}
556         \item{Ensemble averaging}
557      \end{itemize} 
558      \item{Definition of turbulent fluctuations}\\
559      \textbf{Spatial fluctuations:} deviation from representative instantaneous spatial average
560      \begin{itemize}
561         \scriptsize
562         \item{PALM: many statistics calculated on-the-fly as time series, 1D vertical profiles}
563         \item{Not suitable for topography unless a direction of homogeneity exists}
564      \end{itemize}
565      \textbf{Temporal fluctuations}: deviation from representative local temporal average
566      \begin{itemize}
567         \scriptsize
568         \item{Suitable for all applications including topography}
569         \item{Requires much hard disk space and post-processing CPU time}
570         \item{PALM: not natively supported, but following procedure works:}
571         \begin{itemize}
572            \scriptsize
573            \item{Collect time-series during the simulation (2D/3D data output or user-defined time series)}
574            \item{Check for (quasi-)steady turbulent state and sufficient averaging time}
575            \item{Calculate statistics by post-processing making use of the Reynolds decomposition: \\ \par\medskip
576                  $\overline{w'\theta'} = \overline{w\theta} - \overline{w} \overline{\theta} $}
577         \end{itemize}
578      \end{itemize}   
579   \end{itemize}
580\end{frame}
581
582% Folie 21
583\begin{frame}
584   \frametitle{Your Responsibility and Contribution}
585   \footnotesize
586   \par\medskip
587   PALM's topography features have been frequently applied within the last years, but there may be still some parameter combinations which have not been used so far, and which may not work properly.
588   \par\bigskip
589%    For example, the combination of topography and non-cyclic lateral boundary conditions has not yet been tested
590%    because both features have originally been introduced separately for different research projects.
591%    \par\bigskip
592   Therefore, we ask you for your responsibility and contribution:
593   \begin{itemize}
594      \item{Please always check your PALM setup carefully. PALM is not a black box.} 
595      \item{For example, design a simple case and test your expectation.}
596      \item{Please report potential bugs using our trouble ticket system.}
597   \end{itemize}
598\end{frame}
599
600% Folie 22
601\begin{frame}
602   \frametitle{Some recent examples of topography/building applications with PALM}
603   
604   \scriptsize
605   \textbf{Street canyon flows}
606   \par\smallskip
607   \tiny
608   \textbf{Letzel, M.O., M. Krane and S. Raasch 2008}: High resolution urban large-eddy simulation studies from street canyon to neighbourhood scale, Atmos. Env.,
609   \textbf{42}, 8770-8784, doi:10.1016/j.atmosenv.2008.08.001.\\
610   \par\medskip
611
612   \scriptsize
613   \textbf{Turbulence generated by topography}
614   \par\smallskip
615   \tiny
616   \textbf{Esau, I. and I. Repina, 2012}: Wind climate in Kongsfjorden, Svalbard, and attribution of leading wind driving mechanisms through turbulence-resolving simulations. Advances in Meteorology,
617   \textbf{Volume 2012}, Article ID 568454, 16 pages, doi:10.1155/2012/568454.\\
618   \par\medskip
619   
620   \scriptsize
621   \textbf{Airflow within or over building arrays}
622   \par\smallskip
623   \tiny
624   \textbf{Abd Razak A., A. Hagishima, N. Ikegaya and J. Tanimoto, 2013}: Analysis of airflow over building arrays for assessment of urban wind environment. Building and Environment,
625   \textbf{59}, 56-65, doi:10.1016/j.buildenv.2012.08.007. \\
626   \par\smallskip
627   \textbf{Kanda, M., A. Inagaki, T. Miyamoto, M. Gryschka and S. Raasch 2013}: A New Aerodynamic Parameterization for Real Urban Surfaces, Boundary-Layer Meteorol.,
628    \textbf{148}, 357-377, doi:10.1007/s10546-013-9818-x. \\
629   \par\medskip
630       
631   \scriptsize
632   \textbf{Thermal effects of building walls}
633   \par\smallskip
634   \tiny
635   \textbf{Park, S.B., J.J. Baik, S. Raasch and M.O. Letzel 2012}: A large-eddy simulation study of thermal effects on turbulent flow and dispersion in and above a street canyon., J. Appl. Meteor. Climatol.,
636   \textbf{51}, 829-841, doi:10.1175/JAMC-D-11-0180.1.\\
637   \par\medskip
638
639   \scriptsize
640   \textbf{PALM coupled to a building energy model}
641   \par\smallskip
642   \tiny
643   \textbf{Yaghoobian, N., J. Kleissl and K. T. Paw U, 2014}: An Improved Three-Dimensional Simulation of the Diurnally Varying Street-Canyon Flow, Boundary-Layer Meteorol.,
644   doi:http://dx.doi.org/10.1007/s10546-014-9940-4.\\
645\end{frame}
646
647% Folie 22
648\begin{frame}
649   \Large
650   \begin{center} \textcolor{blue!90!black!100}{Topography - Scenario examples} \end{center}
651\end{frame}
652
653% Folie 23
654\begin{frame}
655   \frametitle{Set-up Scenario: Single Street Canyon (I)}
656   \par\smallskip
657   \textbf{Single quasi-2D street canyon in neutral open channel flow with constant bulk velocity}
658   \par\smallskip
659   \begin{itemize}
660      \item{{\tt trunk/EXAMPLES/canyon/}}
661      \begin{itemize}
662         \item{Parameter file \hspace{2cm} {\tt example\_canyon\_p3d}}
663         \item{Run-control file \hspace{1.78cm} {\tt example\_canyon\_rc}}
664         \item{Some documentation \hspace{0.95cm} {\tt example\_canyon.odt}}
665      \end{itemize}
666   \end{itemize}
667   \begin{center}
668      \includegraphics[width=0.85\textwidth]{topography_figures/scenario_ssc_1.png}
669   \end{center}
670\end{frame}
671
672% Folie 24
673\begin{frame}
674   \frametitle{Set-up Scenario: Single Street Canyon (II)}
675   \textbf{The phase average makes use of homogeneity in y-direction:} \\
676   {\tt section\_xz = -1}, {\tt data\_output = \textbf{'u\_xz\_av'}}, {\tt 'v\_xz\_av'}, {\tt 'w\_xz\_av'}
677   \begin{center}
678      \includegraphics[width=0.85\textwidth]{topography_figures/scenario_ssc_2.png}
679   \end{center}
680\end{frame}
681
682% Folie 25
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_ssc_example_1.png}};}
689            \uncover<2->{\node at (0,-0.5) {\includegraphics[width=0.7\textwidth]{topography_figures/scenario_ssc_example_2.png}};}
690            %\uncover<3->{\node at (0,-0.5) {\includegraphics[width=0.7\textwidth]{topography_figures/scenario_ssc_example_3.png}};}
691            \uncover<3->{\node at (-3.5,-0.2) {\includegraphics[width=0.48\textwidth]{topography_figures/scenario_ssc_example_4.png}};}
692            \uncover<4->{\node at (3.5,-0.2) {\includegraphics[width=0.38\textwidth]{topography_figures/scenario_ssc_example_5.png}};}
693         \end{tikzpicture}
694         };
695  \end{tikzpicture}
696\end{frame}
697
698% Folie 26
699\begin{frame}
700   \frametitle{Set-up Scenario: Constant Flux Layer}
701   \small
702   \textbf{Single surface-mounted cube in neutral open channel flow with a constant flux layer}
703   \begin{itemize}
704      \item{{\tt trunk/EXAMPLES/constant\_flux\_layer/}}
705      \begin{itemize}
706         \footnotesize
707         \item{Parameter file \hspace{2cm} {\tt example\_constant\_flux\_layer\_p3d}}
708         \item{Run-control file \hspace{1.79cm} {\tt example\_constant\_flux\_layer\_rc}}
709         \item{Some documentation \hspace{1.02cm} {\tt example\_constant\_flux\_layer.odt}}
710      \end{itemize}
711   \end{itemize}
712   \begin{center}
713      \includegraphics[width=0.85\textwidth]{topography_figures/scenario_cfl.png}
714   \end{center}
715\end{frame}
716
717% Folie 27
718\begin{frame}
719 \begin{tikzpicture}[remember picture, overlay]
720      \node [shift={(6.5 cm, 5cm)}]  at (current page.south west)
721         {%
722         \begin{tikzpicture}[remember picture, overlay]
723            \uncover<1->{\node at (0,-0.5) {\includegraphics[width=0.7\textwidth]{topography_figures/scenario_cfl_example_1.png}};}
724            \uncover<2->{\node at (-3.5,-0.2) {\includegraphics[width=0.45\textwidth]{topography_figures/scenario_cfl_example_2.png}};}
725            \uncover<3->{\node at (3.5,-0.2) {\includegraphics[width=0.38\textwidth]{topography_figures/scenario_cfl_example_3.png}};}
726         \end{tikzpicture}
727         };
728  \end{tikzpicture}
729\end{frame}
730
731% Folie 28
732\begin{frame}
733   \frametitle{Rules of Good Practise}
734   \small
735   \begin{itemize}
736      \item{If you run PALM with topography, make sure that it is really LES...}
737      \begin{itemize}
738         \item{''Large eddies'' are ''small'' between obstacles}
739         \begin{itemize}
740            \item{use fine grid length to resolve turbulence there}
741         \end{itemize}
742         \item{Ratio of resolved to SGS fluxes}
743      \end{itemize} 
744      \item{Check for (quasi-)steady turbulent state and sufficient averaging time.}
745      \begin{itemize}
746         \item{Fluctuations of time series of E, E*, maximum velocity components etc.}
747      \end{itemize}
748      \item{Make sure that your PALM result is independent of numerical parameters such as domain size and grid size.}
749      \begin{itemize}
750         \item{Sensitivity studies}
751      \end{itemize}
752      \item{If you intend to do a comparison with some kind of reference data, it is essential to configure the set-up of PALM
753           in the same way as the reference experiment.}
754      \begin{itemize}
755         \item{For example, if you compare PALM with wind tunnel results, you have to follow the wind tunnel set-up for setting up PALM.}
756      \end{itemize}
757   \end{itemize}
758\end{frame}
759
760\end{document}
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