Changes between Version 200 and Version 201 of doc/app/initialization_parameters

Timestamp:

May 21, 2013 12:58:14 PM (12 years ago)

Author:

fricke

Comment:

--

doc/app/initialization_parameters

@@ -868 +868 @@
 This method effectively damps gravity waves at the inflow boundary in case of non-cyclic lateral boundary conditions (see [#bc_lr bc_lr] or [#bc_ns bc_ns]).
 If the damping factor is too low, gravity waves can develop within the damping domain and if the damping factor is too high, gravity waves can develop in front of the damping domain. 
+
+Detailed information about non-cyclic lateral boundary conditions and the damping function can be found [../../tec/noncyclic here].
 }}}
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@@ -882 +884 @@
 Width of the damping domain of the potential temperature (in m).\\\\
 In case of non-cyclic lateral boundary conditions (see [#bc_lr bc_lr] or [#bc_ns bc_ns]), this parameter determines the range where damping of the potential temperature is applied. The damping domain starts at the inflow boundary and ranges to the value of '''pt_damping_width'''. The intensity of the damping is applied by [#pt_damping_factor pt_damping_factor].
+
+Detailed information about non-cyclic lateral boundary conditions and the damping function can be found [../../tec/noncyclic here].
 }}}
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@@ -1123 +1127 @@
 Boundary condition along x (for all quantities).\\\\
 By default, a cyclic boundary condition is used along x.\\\\
-'''bc_lr''' may also be assigned the values '' 'dirichlet/radiation' '' or '' 'dirichlet/neumann' '' (inflow from left, outflow to the right) or '' 'radiation/dirichlet' '' or '' 'radiation/neumann' '' (inflow from right, outflow to the left). This requires the multi-grid method to be used for solving the Poisson equation for perturbation pressure (see [#psolver psolver]) and it also requires cyclic boundary conditions along y (see [#bc_ns bc_ns]).\\\\
-In case of these non-cyclic lateral boundaries, a Dirichlet condition is used at the inflow for all quantities (initial vertical profiles - see [#initializing_actions initializing_actions] - are fixed during the run) except e, to which a Neumann (zero gradient) condition is applied. At the outflow, a radiation condition (in case of '' radiation '') or a Neumann (zero gradient) condition (in case of '' neumann '') is used for all velocity components, while a Neumann (zero gradient) condition is used for the scalars in both cases. For perturbation pressure Neumann (zero gradient) conditions are assumed both at the inflow and at the outflow.\\\\
+'''bc_lr''' may also be assigned the values '' 'dirichlet/radiation' '' (inflow from left, outflow to the right) or '' 'radiation/dirichlet' '' (inflow from right, outflow to the left). This requires the multi-grid method to be used for solving the Poisson equation for perturbation pressure (see [#psolver psolver]) and it also requires cyclic boundary conditions along y (see [#bc_ns bc_ns]).\\\\
+In case of these non-cyclic lateral boundaries, a Dirichlet condition is used at the inflow for all quantities (initial vertical profiles - see [#initializing_actions initializing_actions] - are fixed during the run) except e, to which a Neumann (zero gradient) condition is applied. At the outflow, a radiation condition is used for all velocity components, whereby the user can choose the calculation of the phase velocity by setting [#use_cmax use_cmax].
+For scalars, a Neumann (zero gradient) condition is used. For the perturbation pressure, Neumann (zero gradient) conditions are assumed both at the inflow and at the outflow.\\\\
 In order to maintain a turbulent state of the flow, it may be neccessary 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].\\\\
 In case of non-cyclic horizontal boundaries [#call_psolver_at_all_substeps call_psolver_at_all_substeps] = ''.T.'' should be used.\\\\
 '''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.
+
+Detailed information about non-cyclic lateral boundary conditions can be found [../../tec/noncyclic here].
 }}}
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@@ -1145 +1152 @@
 '''bc_ns''' may also be assigned the values '' 'dirichlet/radiation' '' or '' 'dirichlet/neumann' '' (inflow from rear ("north"), outflow to the front ("south")) or '' 'radiation/dirichlet' '' or '' 'neumann/dirichlet' '' (inflow from front ("south"), outflow to the rear ("north")). This requires the multi-grid method to be used for solving the Poisson equation for perturbation pressure (see [#psolver psolver]) and it also requires cyclic boundary conditions along x (see
 [#bc_lr bc_lr]).\\\\
-In case of these non-cyclic lateral boundaries, a Dirichlet condition is used at the inflow for all quantities (initial vertical profiles - see [#initializing_actions initializing_actions] - are fixed during the run) except e, to which a Neumann (zero gradient) condition is applied. At the outflow, a radiation condition (in case of '' radiation '') or a Neumann (zero gradient) condition (in case of '' neumann '') is used for all velocity components, while a Neumann (zero gradient) condition is used for the scalars in both cases. For perturbation pressure Neumann (zero gradient) conditions are assumed both at the inflow and at the outflow.\\\\
+In case of these non-cyclic lateral boundaries, a Dirichlet condition is used at the inflow for all quantities (initial vertical profiles - see [#initializing_actions initializing_actions] - are fixed during the run) except e, to which a Neumann (zero gradient) condition is applied. At the outflow, a radiation condition is used for all velocity components, whereby the user can choose the calculation of the phase velocity by setting [#use_cmax use_cmax].
+For scalars, a Neumann (zero gradient) condition is used. For the perturbation pressure, Neumann (zero gradient) conditions are assumed both at the inflow and at the outflow.\\\\
 For further details regarding non-cyclic lateral boundary conditions see [#bc_lr bc_lr].
 }}}
@@ -1662 +1670 @@
 The distance of the recycling plane from the inflow boundary can be set with parameter [#recycling_width recycling_width]. The heigth above ground above which the turbulence signal is not used for recycling and the width of the layer within the magnitude of the turbulence signal is damped from 100% to 0% can be set with parameters [#inflow_damping_height inflow_damping_height] and [#inflow_damping_width inflow_damping_width].\\\\
 The detailed setup for a turbulent inflow is described in [../examples/turbinf here].
+}}}
+|----------------
+{{{#!td style="vertical-align:top"
+[=#use_cmax '''use_cmax''']
+}}}
+{{{#!td style="vertical-align:top"
+L
+}}}
+{{{#!td style="vertical-align:top"
+.T.
+}}}
+{{{#!td
+Parameter to choose the calculation method of the phase velocity at the outflow in case of non-cyclic lateral boundary conditions.
+
+In case of non-cyclic lateral boundary conditions, radiation boundary conditions are used for the velocity components at the outflow boundary.
+By setting [#use_cmax use_cmax] = ''.T.'', the maximum phase velocity that ensures numerical stability (CFL-condition) is used in order that the radiation boundary conditions are simplified in this way that the phase velocity must not be calculated after every time step.
+
+Setting [#use_cmax use_cmax] = ''.F.'', the phase velocity is calculated after Orlanski (1976) after every time step and averaged along the outflow.
+
+Detailed information about the radiation boundary conditions can be found [../../tec/noncyclic here].
 }}}
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