Changes between Version 315 and Version 316 of doc/app/initialization_parameters

Timestamp:

Mar 20, 2017 10:32:36 AM (8 years ago)

Author:

hellstea

Comment:

--

doc/app/initialization_parameters

@@ -1302 +1302 @@
 In order to maintain a turbulent state of the flow, it may be necessary to continuously impose perturbations on the horizontal velocity field in the vicinity of the inflow throughout the whole run. This can be switched on using [../d3par#create_disturbances create_disturbances]. The horizontal range to which these perturbations are applied is controlled by the parameters [#inflow_disturbance_begin inflow_disturbance_begin] and [#inflow_disturbance_end inflow_disturbance_end]. The vertical range and the perturbation amplitude are given by [../d3par#disturbance_level_b disturbance_level_b], [../d3par#disturbance_level_t disturbance_level_t], and [../d3par#disturbance_amplitude disturbance_amplitude]. The time interval at which perturbations are to be imposed is set by [../d3par#dt_disturb dt_disturb]. Note that these inflow perturbances are added '''in addition''' to the standard perturbances that are activated with [../d3par#create_disturbances create_disturbances]. The standard perturbances can be deactivated by setting the d3par-parameter [../d3par#disturbance_energy_limit disturbance_energy_limit] = 0.0 .\\\\
 In case of non-cyclic horizontal boundaries [#call_psolver_at_all_substeps call_psolver_at_all_substeps] = ''.T.'' should be used.\\\\
-In case of nested run, except if [#nesting_mode nesting_mode]='vertical', the default value of '''bc_lr''' in the nest domains is not '' 'cyclic' '' but '' 'nested' '' instead. For the root domain of a nested run  the default is '' 'cyclic' '' as usually.\\\\
+In case of nested run, except if [#nesting_mode nesting_mode]='' 'vertical' '', the default value of '' 'bc_lr' '' in the nest domains is not '' 'cyclic' '' but '' 'nested' '' instead. For the root domain of a nested run  the default is '' 'cyclic' '' as usually.\\\\
 '''Note:'''\\
 Using non-cyclic lateral boundaries requires very sensitive adjustments of the inflow (vertical profiles) and the bottom boundary conditions, e.g. a surface heating should not be applied near the inflow boundary because this may significantly disturb the inflow. Please check the model results very carefully.
@@ -1357 +1357 @@
 Allowed values are '' 'dirichlet' '' (p(k=nz+1)= 0.0) or '' 'neumann' '' (p(k=nz+1)=p(k=nz)).\\\\
 Simultaneous use of Neumann boundary conditions both at the top and bottom boundary ([#bc_p_b bc_p_b]) yields no consistent solution for the perturbation pressure in case that the multigrid method is used for solving the Poisson equation (see [#psolver psolver]), and should be avoided. Since at the bottom boundary the Neumann condition  is a good choice (see [#bc_p_b bc_p_b]), in that case, a Dirichlet condition should be set at the top boundary.\\\\
-In case of nested run, the default is not 'dirichlet', but 'neumann' instead.\\\\
+In case of nested run, the default value of '''bc_p_t''' in the nest domains is not '' 'dirichlet' '' but '' 'neumann' '' instead. For the root domain of a nested run the default is '' 'dirichlet' '' as usually.\\\\
+
 Note that therefore the Poisson equation for perturbation pressure has all-Neumann boundary condition in nest-domains. This means that the solution is only determined up to a constant. Or in other words, the average value of the pressure is arbitrary. This implies that the convergence rate is usually somewhat lower than when Dirichlet condition is used at least on one of the boundaries. Users using the nesting system should pay attention to this and adjust the steering parameters of the multigrid solver carefully to achieve sufficient convergence without sacrificing too much computing time for the perturbation-pressure solution. 
 }}}