# Changeset 1198 for palm/trunk/TUTORIAL/SOURCE/exercise_neutral.tex

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Timestamp:
Jul 4, 2013 12:38:18 PM (11 years ago)
Message:

typos removed

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 r954 \frametitle{Exercise 2: Neutrally Stratified  Atmospheric Boundary Layer} \begin{itemize} \item The simulation should be for a neutrally stratified atmospheric boundary layer. \item<2-> The flow should be driven by a constant large-scale pressure gradient, i.e. a geostrophic wind. \item A neutrally stratified atmospheric boundary layer shall be simulated. \item<2-> The flow shall be driven by a constant large-scale pressure gradient, i.e. a geostrophic wind. \item<3-> At the end of the simulation, turbulence as well as the mean flow should be in a stationary state. \end{itemize} \item<3-> Is it really a large-eddy simulation, i.e. are the subgrid-scale fluxes much smaller than the resolved-scale fluxes? \vspace{1em} \item<4-> How does the turbulence spectra of $u$, $v$, $w$, along $x$ and along $y$ look like?\\ \item<4-> How do the turbulence spectra of $u$, $v$, $w$ along $x$ and along $y$ look like?\\ Can you identify the inertial subrange? \end{itemize} \item<3-> The 1D-model (\texttt{\textcolor{blue}{initializing\_actions} = 'set\_1d-model\_profiles'}) is mainly controlled by parameters \texttt{\textcolor{blue}{end\_time\_1d}} and \texttt{\textcolor{blue}{damp\_level\_1d}}. Please keep in mind that the profiles from the 1D-model should also be in a stationary state. \vspace{0.5em} \item<3-> Output of vertical profile data generated by the 1D-model is controlled by parameter \texttt{\textcolor{blue}{dt\_pr\_1d}}. It is in ASCII-format and it is written into a separate file. You can include the profiles of the 1D-model, which are used to initialize the 3D-model, in the standard profile data output of the 3D-model (which is controlled by parameter \texttt{\textcolor{blue}{data\_output\_pr}}) by adding a \texttt{'\#'} sign to the respective output quantitiy, e.g. \texttt{\textcolor{blue}{data\_output\_pr} = '\#u'}. \item<3-> Output of vertical profile data generated by the 1D-model is controlled by parameter \texttt{\textcolor{blue}{dt\_pr\_1d}}. It is in ASCII-format and it is written into a separate file. You can include the profiles of the 1D-model, which are used to initialize the 3D-model, in the standard profile data output of the 3D-model (which is controlled by parameter \texttt{\textcolor{blue}{data\_output\_pr}}) by adding a \texttt{'\#'} sign to the respective output quantity, e.g. \texttt{\textcolor{blue}{data\_output\_pr} = '\#u'}. \vspace{0.5em} \item<3-> For the 1D-model, please set \texttt{\textcolor{blue}{mixing\_length} = 'blackadar'} and \texttt{\textcolor{blue}{dissipation\_1d} = 'detering'} in order to get a correct mean boundary layer wind profile. The default settings of these parameters would switch the turbulence parameterization of the 1D-model to the SGS-parameterization of the 3D-LES-model, which represents only the SGS-parts of turbulence. However, for this exercise the 1D-model has to parameterize all scales of turbulence (i.e. it should be used as a RANS-model). \item<3-> For the 1D-model, please set \texttt{\textcolor{blue}{mixing\_length\_1d} = 'blackadar'} and \texttt{\textcolor{blue}{dissipation\_1d} = 'detering'} in order to get a correct mean boundary layer wind profile. The default settings of these parameters would switch the turbulence parameterization of the 1D-model to the SGS-parameterization of the 3D-LES-model, which represents only the SGS-parts of turbulence. However, for this exercise the 1D-model has to parameterize all scales of turbulence (i.e. it should be used as a RANS-model). \end{itemize}