Changes between Version 17 and Version 18 of doc/tec/noncyclic
- Timestamp:
- May 21, 2013 1:10:14 PM (11 years ago)
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doc/tec/noncyclic
v17 v18 61 61 For the scalar quantities, Neumann boundary conditions are used at the outflow boundary which is the simplest way. 62 62 For 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]).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/#use_cmax use_cmax], [../../app/inipar/#bc_lr bc_lr] and [../../app/inipar/#bc_ns bc_ns]). 64 64 For the radiation condition, the Sommerfeld radiation equation is solved at the outflow 65 65 {{{ … … 71 71 In PALM, based on (5), the radiation boundary condition is realized in two ways as follows. 72 72 73 ==== Radiation boundary condition I====73 ==== Variable Phase velocity ==== 74 74 75 75 The phase velocity c,,ψ,, (also called convective velocity) is calculated after Orlanski (1976): … … 132 132 }}} 133 133 134 ==== Radiation boundary condition II====134 ==== Constant Phase velocity ==== 135 135 136 This is a simplified version of radiation boundary condition I, where just c,,ψ,, = c,,max,, is used in (5). Thisleads to a more simple radiation boundary condition (here e.g. for a left-right flow along positive x-direction):136 Setting 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): 137 137 {{{ 138 138 #!Latex