Changeset 945 for palm/trunk/TUTORIAL/SOURCE/sgs_models.tex
- Timestamp:
- Jul 17, 2012 3:43:01 PM (12 years ago)
- File:
-
- 1 edited
Legend:
- Unmodified
- Added
- Removed
-
palm/trunk/TUTORIAL/SOURCE/sgs_models.tex
r915 r945 19 19 \usepackage{amssymb} 20 20 \usepackage{multicol} 21 \usepackage{ float}21 \usepackage{pdfcomment} 22 22 23 23 \institute{Institut fÃŒr Meteorologie und Klimatologie, Leibniz UniversitÀt Hannover} … … 43 43 \author{Siegfried Raasch} 44 44 45 % Notes:46 % jede subsection bekommt einen punkt im menu (vertikal ausgerichtet.47 % jeder frame in einer subsection bekommt einen punkt (horizontal ausgerichtet)48 45 \begin{document} 49 46 … … 167 164 168 165 169 \section{Deardoff Modification}170 \subsection{Deardoff Modification}171 172 % Folie 7173 \begin{frame}174 \frametitle{Deardorff (1980) Modification (Used in PALM) (I)}175 \footnotesize176 \onslide<1->{177 $ \nu_T = Cql = C_M \Lambda \sqrt{\bar{e}} $ \quad \textbf{with} \quad $ \bar{e} = \frac{\overline{u_i' u_i'}}{2} $ \quad \textbf{SGS-turbulent kinetic energy}}178 \normalsize179 \begin{itemize}180 \item<2->{The SGS-TKE allows a much better estimation of the velocity scale for the SGS fluctuations and also contains information about the past history of the local fluid.}181 \end{itemize}182 \onslide<3->{183 $ C_M = const. = 0.1 $184 \par\bigskip185 \scriptsize186 $ \Lambda = \begin{cases} min\left( 0.7 \cdot z, \Delta \right), & \textbf{unstable or neutral stratification} \\187 min\left( 0.7 \cdot z, \Delta, 0.76 \sqrt{\bar{e}} \left[ \frac{g}{\Theta_0} \frac{\partial \bar{\Theta}}{\partial z} \right]^{-1/2} \right), & \textbf{stable stratification}188 \end{cases} $189 \normalsize190 \par\bigskip191 $ \Delta = \left( \Delta x \Delta y \Delta z \right)^{1/3} $ }192 \end{frame}193 194 % Folie 8195 \begin{frame}196 \frametitle{Deardorff (1980) Modification (Used in PALM) (II)}197 \begin{itemize}198 \item{SGS-TKE from prognostic equation}199 \end{itemize}200 $ \frac{\partial \bar{e}}{\partial t} = -\bar{u_k} \frac{\partial \bar{e}}{\partial x_k} - \tau_{ki} \frac{\partial \bar{u_i}}{\partial x_k} + \frac{g}{\Theta_0} \overline{u_3' \Theta'} - \frac{\partial}{\partial x_k} \left\{ \overline{u_k' \left( e' + \frac{\pi'}{\rho_0} \right)} \right\} - \epsilon $201 \par\bigskip202 $ \frac{\partial}{\partial x_k} \left[ \overline{u_k' \left( e' + \frac{\pi'}{\rho_0} \right)} \right] = - \frac{\partial}{\partial x_k} \nu_e \frac{\partial \bar{e}}{\partial x_k} $203 \par\bigskip204 $ \nu_e = 2 \nu_T $205 \par\bigskip206 $ \epsilon = C_{\epsilon} \frac{\bar{e}^{3/2}}{\Lambda} \qquad \qquad C_{\epsilon} = 0.19 + 0.74\frac{\Lambda}{\Delta} $207 \end{frame}208 209 % Folie 9210 \begin{frame}211 \frametitle{Deardorff (1980) Modification (Used in PALM) (III)}212 \begin{itemize}213 \item{There are still problems with this parameterization:}214 \begin{itemize}215 \item[-]<2->{The model overestimates the velocity shear near the wall.}216 \item[-]<3->{$\textrm{C}_\mathrm{M}$ is still a constant but actually varies for different types of flows.}217 \item[-]<4->{Backscatter of energy from the SGS-turbulence to the resolved-scale flow can not be considered.}218 \end{itemize}219 \item<5->{Several other SGS models have been developed:}220 \begin{itemize}221 \item[-]<5->{Two part eddy viscosity model (Sullivan, et al.)}222 \item[-]<6->{Scale similarity model (Bardina et al.)}223 \item[-]<7->{Backscatter model (Mason)}224 \end{itemize}225 \item<8->{However, for fine grid resolutions ($\textrm{E}_\mathrm{SGS} << \ \textrm{E}$) LES results become almost independent226 from the different models (Beare et al., 2006, BLM).}227 \end{itemize}228 \end{frame}229 230 231 \section{Summary / Important Points for Beginners}232 \subsection{Summary / Important Points for Beginners}233 234 % Folie 10235 \begin{frame}236 \frametitle{Summary / Important Points for Beginners (I)}237 \begin{columns}[c]238 \column[T]{0.4\textwidth}239 \includegraphics<2-7>[width=\textwidth]{sgs_models_figures/Important_Points/Important_Points_1_2.png}240 \includegraphics<8>[width=\textwidth]{sgs_models_figures/Important_Points/Important_Points_1_8.png}241 \includegraphics<9>[width=\textwidth]{sgs_models_figures/Important_Points/Important_Points_1_9.png}242 \includegraphics<10>[width=\textwidth]{sgs_models_figures/Important_Points/Important_Points_1_10.png}243 \onslide<8-10>{\begin{flushright} \begin{tiny} after Schatzmann and Leitl (2001) \end{tiny} \end{flushright}}244 \column[T]{0.2\textwidth}245 \vspace{0.9cm}246 \includegraphics<8-10>[width=0.7\textwidth]{sgs_models_figures/Important_Points/Important_Points_1_arrow.png}247 \par248 \onslide<8->{\begin{small} fluctuations (\textbf{u},c) \end{small}}249 \par\bigskip250 \thicklines251 \onslide<9->{\mbox{\line(6,0){5} \, \line(1,0){5} \, \line(1,0){5} \quad \begin{small} {critical concentration level} \end{small}}}252 \vspace{1cm}253 254 \includegraphics<8-10>[width=0.7\textwidth]{sgs_models_figures/Important_Points/Important_Points_1_arrow.png}255 \par256 \onslide<8->{\begin{small} smooth result \end{small}}257 \column[T]{0.4\textwidth}258 \includegraphics<1-2>[width=\textwidth]{sgs_models_figures/Important_Points/Important_Points_1_1.png}259 \includegraphics<3>[width=\textwidth]{sgs_models_figures/Important_Points/Important_Points_1_3.png}260 \includegraphics<4>[width=\textwidth]{sgs_models_figures/Important_Points/Important_Points_1_4.png}261 \includegraphics<5-10>[width=\textwidth]{sgs_models_figures/Important_Points/Important_Points_1_5.png}262 \vspace{1.3cm}263 \includegraphics<6>[width=\textwidth]{sgs_models_figures/Important_Points/Important_Points_1_6.png}264 \uncover<7->{\includegraphics[width=\textwidth]{sgs_models_figures/Important_Points/Important_Points_1_7.png}}265 \end{columns}266 \end{frame}267 268 % Folie 11269 \begin{frame}270 \frametitle{Summary / Important Points for Beginners (II)}271 For an LES it always has to be guaranteed that the main energy containing eddies of the respective272 turbulent flow can really be simulated by the numerical model:273 \begin{itemize}274 \item<2->{The grid spacing has to be fine enough.}275 \item<3->{$\textrm{E}_\mathrm{SGS} < (<<) \ \textrm{E} $}276 \item<4->{The inflow/outflow boundaries must not effect the flow turbulence \\277 (therefore cyclic boundary conditions are used in most cases).}278 \item<5->{In case of homogeneous initial and boundary conditions, the onset of turbulence279 has to be triggered by imposing random fluctuations.}280 \item<6->{Simulations have to be run for a long time to reach a stationary state and stable statistics.}281 \end{itemize}282 \end{frame}283 284 285 \section{Example Output}286 \subsection{Example Output}287 288 % Folie 12289 \begin{frame}290 \frametitle{Example Output (I)}291 \begin{itemize}292 \item{LES of a convective boundary layer}293 \end{itemize}294 \includegraphics<1>[width=\textwidth]{sgs_models_figures/Example_Output_1/Example_Output_1_1.png}295 \includegraphics<2>[width=\textwidth]{sgs_models_figures/Example_Output_1/Example_Output_1_2.png}296 \includegraphics<3>[width=\textwidth]{sgs_models_figures/Example_Output_1/Example_Output_1_3.png}297 \includegraphics<4>[width=\textwidth]{sgs_models_figures/Example_Output_1/Example_Output_1_4.png}298 \includegraphics<5>[width=\textwidth]{sgs_models_figures/Example_Output_1/Example_Output_1_5.png}299 \includegraphics<6>[width=\textwidth]{sgs_models_figures/Example_Output_1/Example_Output_1_6.png}300 \includegraphics<7>[width=\textwidth]{sgs_models_figures/Example_Output_1/Example_Output_1_7.png}301 \end{frame}302 303 % Folie 13304 \begin{frame}305 \frametitle{Example Output (II)}306 \begin{itemize}307 \item{LES of a convective boundary layer}308 \end{itemize}309 \begin{center}310 \includegraphics[width=0.8\textwidth]{sgs_models_figures/Example_output_2.png}311 power spectrum of vertical velocity312 \end{center}313 \end{frame}314 315 % Folie 14316 \begin{frame}317 \frametitle{Some Symbols}318 \begin{columns}[c]319 \column{0.6\textwidth}320 \begin{tabbing}321 $u_i \quad (i = 1,2,3)$ \quad \= velocity components \\322 $u,v,w$ \\323 324 \\325 326 $x_i \quad (i = 1,2,3)$ \> spatial coordinates \\327 $x,y,z$ \\328 329 \\330 331 $\Theta$ \> potential temperature \\ \\332 333 $\Psi$ \> passive scalar \\ \\334 335 $T$ \> actual Temperatur \\ \\336 \end{tabbing}337 \column{0.4\textwidth}338 \begin{tabbing}339 $\Phi = gz$ \quad \= geopotential \\ \\340 341 $p$ \> pressure \\ \\342 343 $\rho$ \> density \\ \\344 345 $f_i$ \> Coriolis Parameter \\ \\346 347 $\epsilon_{ijk}$ \> alternating symbol \\ \\348 349 $\nu, \nu_\Psi$ \> molecular diffusivity \\ \\350 351 $Q, Q_\Psi$ \> sources or sinks \\ \\352 \end{tabbing}353 \end{columns}354 \end{frame}355 166 \end{document}
Note: See TracChangeset
for help on using the changeset viewer.