
[Sponsors] 
July 3, 2013, 10:12 
Alternative boundary treatment on cellcentered scheme

#1 
Member
Dokeun, Hwang
Join Date: Apr 2010
Posts: 71
Rep Power: 9 
Dear all
I used ghost cell concept for euler solver but confused how can I compute gradient of flow properties at boundary face for viscous flux. Because I need gradients of velocity and Temperature at ghost cell for face centered properties, but I have no idea about this. For your understanding I'd like to use modified gradient described in Blazek's Is there any alternative or breakthrough? 

July 3, 2013, 11:35 

#2  
Senior Member
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 3,649
Rep Power: 41 
Quote:
In a FV method is quite natural to prescribe the flux at a boundary. FOr example mass: zero flux on a notpermeable wall, prescribed flow rate on inflow, etc momentum: zero convective flux a notpermeable wall, prescribed flux for fixed flow rate. The diffusive flux is imposed such that the velocity on a boundary is prescribed, for example, at first order, a normal derivatives of the velocity on a wall is mu*du/dywall > mu * (u(wall+1)  u(wall1))/(2*dy) = mu*u(wall+1)/dy temperature: quite natural if you have adiabatic or fixed heat flux q = k*Grad T and so on ... 

July 11, 2013, 09:59 

#3  
Member
Dokeun, Hwang
Join Date: Apr 2010
Posts: 71
Rep Power: 9 
Quote:
Thank you for your kind reply with example. I guess I understood your explanation. But I'd like to be checked the thought below and get some more about boundary condition. Quote:
How can I implement viscous flux for subsonic boundary condition? Thank you in advance 

Thread Tools  
Display Modes  


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Solution Diverging with Trimmer Mesh  rietuk  STARCCM+  8  February 27, 2013 05:50 
Import problem  ARC  Open Source Meshers: Gmsh, Netgen, CGNS, ...  0  February 27, 2010 11:56 
Cell check and Boundary check errors  AB  Siemens  4  October 28, 2004 13:04 
Node centered and cell centered.  Confused.  Main CFD Forum  9  August 29, 2003 13:54 
Mac Cormack scheme and use of PML boundary conditi  vineet kshirsagar  Main CFD Forum  1  January 13, 2002 02:46 