Changes between Version 17 and Version 18 of doc/tec/noncyclic


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Timestamp:
May 21, 2013 1:10:14 PM (11 years ago)
Author:
fricke
Comment:

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  • doc/tec/noncyclic

    v17 v18  
    6161For the scalar quantities, Neumann boundary conditions are used at the outflow boundary which is the simplest way.
    6262For the velocity components, a Neumann condition would require to be considered in the solution of the Poisson equation for perturbation pressure, which has not been realized so far, because it requires some technical effort.
    63 Instead, PALM offers two types of radiation boundary conditions for the velocity components, which are not in conflict with the pressure solver (see [../../app/inipar/#bc_lr bc_lr] and [../../app/inipar/#bc_ns bc_ns]).
     63Instead, PALM offers two types of radiation boundary conditions for the velocity components, which are not in conflict with the pressure solver (see [../../app/inipar/#use_cmax use_cmax], [../../app/inipar/#bc_lr bc_lr] and [../../app/inipar/#bc_ns bc_ns]).
    6464For the radiation condition, the Sommerfeld radiation equation is solved at the outflow
    6565{{{
     
    7171In PALM, based on (5), the radiation boundary condition is realized in two ways as follows.
    7272
    73 ==== Radiation boundary condition I ====
     73==== Variable Phase velocity ====
    7474
    7575The phase velocity c,,ψ,, (also called convective velocity) is calculated after Orlanski (1976):
     
    132132}}}
    133133
    134 ==== Radiation boundary condition II ====
     134==== Constant Phase velocity ====
    135135
    136 This is a simplified version of radiation boundary condition I, where just c,,ψ,, = c,,max,, is used in (5). This leads to a more simple radiation boundary condition (here e.g. for a left-right flow along positive x-direction):
     136Setting c,,ψ,, = c,,max,, in (5) leads to a more simple radiation boundary condition (here e.g. for a left-right flow along positive x-direction):
    137137{{{
    138138#!Latex