Changes between Version 124 and Version 125 of doc/app/particle_parameters


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Timestamp:
Jun 10, 2014 5:37:17 PM (10 years ago)
Author:
suehring
Comment:

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  • doc/app/particle_parameters

    v124 v125  
    643643{{{#!td
    644644Use subgrid-scale velocities for particle advection.\\
    645 These velocities are calculated from the resolved and subgrid-scale TKE using the Monte-Carlo random-walk method described by Weil et al. (2004, JAS, 61, 2877-2887). When using this method, the timestep for the advancement of the particles is limited by the so-called Lagrangian time scale. This may be smaller than the current LES timestep so that several particle (sub-) timesteps have to be carried out within one LES timestep. In order to limit the number of sub-timesteps (and to limit the CPU-time), the minimum value for the particle timestep is defined by the package parameter [#dt_min_part dt_min_part].\\\\
    646 Setting '''use_sgs_for_particles''' = ''.T.'' automatically forces [../inipar#use_upstream_for_tke use_upstream_for_tke] = ''.T.''. This inhibits the occurrence of large (artificial) spatial gradients of the subgrid-scale TKE which otherwise would lead to wrong results for the particle advection.
     645These velocities are calculated from the resolved and subgrid-scale TKE using the Monte-Carlo random-walk method described by Weil et al. (2004, JAS, 61, 2877-2887). When using this method, the timestep for the advancement of the particles is limited by the so-called Lagrangian time scale. This may be smaller than the current LES timestep so that several particle (sub-) timesteps have to be carried out within one LES timestep. In order to limit the number of sub-timesteps (and to limit the CPU-time), the minimum value for the particle timestep is defined by the package parameter [#dt_min_part dt_min_part].
    647646}}}
    648647|----------------