Collaboration diagram for Common:

Variables
integer, save	irun
	alias for boundary conditions

integer, save	irunh
	alias for boundary conditions

double precision, save	viscv0
	reference volume viscosity (noted $\kappa$ in the equation expressing $\tens{\sigma}$ in the paragraph dedicated to iviscv) always useful, it is the used value, unless the user specifies the volume viscosity in the user subroutine cs_user_physical_properties

integer, save	ippred
	pressure predicion by an evolution equation

integer, save	igrdpp
	indicates whether the pressure should be updated (=1) or not (=0) after the solution of the acoustic equation always usef

integer, save	icfgrp
	indicates if the boundary conditions should take into account (=1) or not (=0) the hydrostatic balance.

Detailed Description

Variable Documentation

◆ icfgrp

integer, save icfgrp

indicates if the boundary conditions should take into account (=1) or not (=0) the hydrostatic balance.

Always useful.

In the cases where gravity is predominant, taking into account the hydrostatic pressure allows to get rid of the disturbances which may appear near the horizontal walls when the flow is little convective.

Otherwise, when icfgrp=0, the pressure condition is calculated from the solution of the unidimensional Euler equations for a perfect gas near a wall, for the variables "normal velocity", "density" and "pressure":

Case of an expansion (M <= 0):

$\begin{align*} P_p &= 0 & \textrm{if } 1 + \displaystyle\frac{\gamma-1}{2}M<0 \\ P_p &= P_i \left(1 + \displaystyle\frac{\gamma-1}{2}M\right) ^{\frac{2\gamma}{\gamma-1}} & \textrm{otherwise} \end{align*}$

Case of a schock (M > 0):

$\begin{eqnarray*} P_p = P_i \left(1 + \displaystyle\frac{\gamma(\gamma+1)}{4}M^2 +\gamma M \displaystyle\sqrt{1+\displaystyle\frac{(\gamma+1)^2}{16}M^2}\right) \end{eqnarray*}$

with $M = \displaystyle\frac{\vect{u}_i \cdot \vect{n}}{c_i}$ , internal Mach number calculated with the variables taken in the cell.

◆ igrdpp

integer, save igrdpp

indicates whether the pressure should be updated (=1) or not (=0) after the solution of the acoustic equation always usef

◆ ippred

integer, save ippred

pressure predicion by an evolution equation

◆ irun

integer, save irun

alias for boundary conditions

◆ irunh

integer, save irunh

alias for boundary conditions

◆ viscv0

double precision, save viscv0

reference volume viscosity (noted $\kappa$ in the equation expressing $\tens{\sigma}$ in the paragraph dedicated to iviscv) always useful, it is the used value, unless the user specifies the volume viscosity in the user subroutine cs_user_physical_properties

Variables