Changeset 4774
- Timestamp:
- 2014-09-18T14:36:51+02:00 (10 years ago)
- Location:
- branches/2014/dev_r4650_UKMO12_CFL_diags_take2/DOC/TexFiles
- Files:
-
- 3 edited
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branches/2014/dev_r4650_UKMO12_CFL_diags_take2/DOC/TexFiles/Chapters/Chap_DIA.tex
r4153 r4774 1386 1386 \\ 1387 1387 1388 \section{Courant numbers} 1389 Courant numbers provide a theoretical indication of the model's numerical stability. The advective Courant numbers can be calculated according to 1390 \begin{equation} 1391 \label{eq:CFL} 1392 C_u = |u|\frac{\rdt}{e_{1u}}, \quad C_v = |v|\frac{\rdt}{e_{2v}}, \quad C_w = |w|\frac{\rdt}{e_{3w}} 1393 \end{equation} 1394 in the zonal, meridional and vertical directions respectively. The vertical component is included although it is not strictly valid as the vertical velocity is calculated from the continuity equation rather than as a prognostic variable. Physically this represents the rate at which information is propogated across a grid cell. Values greater than 1 indicate that information is propagated across more than one grid cell in a single time step. 1395 1396 The variables can be activated by setting the \np{nn\_diacfl} namelist parameter to 1 in the \ngn{namctl} namelist. The diagnostics will be written out to an ascii file named cfl\_diagnostics.ascii. In this file the maximum value of $C_u$, $C_v$, and $C_w$ are printed at each timestep along with the coordinates of where the maximum value occurs. At the end of the model run the maximum value of $C_u$, $C_v$, and $C_w$ for the whole model run is printed along with the coordinates of each. The maximum values from the run are also copied to the ocean.output file. 1388 1397 1389 1398 -
branches/2014/dev_r4650_UKMO12_CFL_diags_take2/DOC/TexFiles/Chapters/Chap_DYN.tex
r4560 r4774 795 795 %> > > > > > > > > > > > > > > > > > > > > > > > > > > > 796 796 \begin{figure}[!t] \begin{center} 797 \includegraphics[width=0.7\textwidth]{./TexFiles/Figures/Fig_ time_split.pdf}797 \includegraphics[width=0.7\textwidth]{./TexFiles/Figures/Fig_DYN_dynspg_ts.pdf} 798 798 \caption{ \label{Fig_DYN_dynspg_ts} 799 799 Schematic of the split-explicit time stepping scheme for the external -
branches/2014/dev_r4650_UKMO12_CFL_diags_take2/DOC/TexFiles/Namelist/namctl
r4147 r4774 13 13 ! (no physical validity of the results) 14 14 nn_timing = 0 ! timing by routine activated (=1) creates timing.output file, or not (=0) 15 nn_diacfl = 0 ! Write out cfl diagnostics (=1) in cfl_diagnostics.ascii, or not (=0) 15 16 /
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