Changes between Version 44 and Version 45 of doc/tec/bc

Timestamp:

Oct 15, 2018 2:21:52 PM (6 years ago)

Author:

suehring

Comment:

--

doc/tec/bc

@@ -315 +315 @@
 Although the method does provide correlated turbulence, it only generates statistical correlation. Large coherent structures like a hexagonal pattern produced by convection cannot be covered by this method. So far, turbulence is only added to the three wind components. No perturbations are added to the subgrid-scale turbulent-kinetic energy and potential temperature.
 
-To use the method, an input file containing all necessary profiles needs to be provided (see [attachment:STG_PROFILES:wiki:doc/app/iofiles example file]) as well as setting the namelist parameter ''use_synthetic_turbulence_generator'' to ''True'' within namelist ''stg_par''. Be sure that the input file is added to the list of input files in your ''.palm.iofiles'' like so:
+If switched on, the turbulence generator imposed turbulent fluctuations on all lateral boundaries with Dirichlet boundary conditions for the velocity components. For example, if the offline nesting is switched on, where all four lateral boundaries are non-cyclic, the turbulence generator applied at all lateral boundaries. 
+
+The turbulence generator can be operated in two ways, with prescribed or with parametrized turbulence information. 
+The turbulence generator requires information about the length and time scales of turbulence, as well as height-dependent information about the Reynolds stress. 
+'''Method 1:''' If these information is available, e.g. from measurements or from a previous simulation, it can be provided via an ASCII file which contains all necessary information, see [attachment:STG_PROFILES:wiki:doc/app/iofiles example file], which will be read automatically by PALM if the namelist parameter ''use_synthetic_turbulence_generator'' is set to ''True'' within namelist ''stg_par''. Be sure that the input file is added to the list of input files in your ''.palm.iofiles'' like so:
 {{{
 STG_PROFILES    in:locopt    d3#:d3r    $base_data/$fname/INPUT    _iprf
 }}}
 and named with the suffix ''_iprf'' in your ''INPUT'' directory. Please have look at the list of [wiki:/doc/app/iofiles#STG_PROFILES input and output files] for a detailed description of the input file.
+'''Method 2:''' In many cases, however, detailed information about the Reynolds stress and turbulent length scales are not available, so that these information need to be parametrized. If no ASCII input file is provided, this will be done automatically. Further, turbulence statistics will be adjusted automatically, so that the turbulence generator can account for non-stationary situations. Parametrization of the Reynolds stress follows [#rotach1996 Rotach et al. (1996)]
+An description of the applied turbulence parametrization will follow soon. 
 
 
@@ -565 +571 @@
 * [=#kim2013] '''Kim Y, Castro IP, Xie ZT.''' 2013. Divergence-free turbulence inflow conditions for large-eddy simulations with incompressible flow solvers. Comput. Fluids. 84: 56–68
 
+* [=#rotach1996] '''Rotach M, Gryning SE, Tassone C.''' 1996. A two-dimensional Lagrangian stochastic dispersion model for daytime condtions. Q.J.R. Meteorol. Soc. 122: 367–389.
+
 * [=#briscolini1989] '''Briscolini M, and Santangelo P.''' 1989. Development of the mask method for incompressible unsteady flows. J. Comput. Phys. 84: 57–75.