Changes between Version 102 and Version 103 of doc/app/particle_parameters

Timestamp:

Sep 14, 2010 8:13:19 AM (14 years ago)

Author:

suehring

Comment:

--

doc/app/particle_parameters

@@ -536 +536 @@
 The length of the tail is controlled by parameters [#maximum_number_of_tailpoints maximum_number_of_tailpoints], [#maximum_tailpoint_age maximum_tailpoint_age], and [#minimum_tailpoint_distance minimum_tailpoint_distance].
 }}}
+|----------------
+{{{#!td style="vertical-align:top"
+[=#use_sgs_for_particles '''use_sgs_for\\_particles''']
+}}}
+{{{#!td style="vertical-align:top"
+L
+}}}
+{{{#!td style="vertical-align:top"
+.F.
+}}}
+{{{#!td
+Use subgrid-scale velocities for particle advection.\\
+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].\\\\
+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.
+}}}