[CIG-MC] Reflective boundary condition in CitcomCU

[Shijie Zhong]

Hi Ting,

Reflective BC implies that Vn=0 and shear stress =0. Your modification should work as well. 


Shijie Zhong, Professor
Department of Physics
University of Colorado at Boulder
Boulder, CO 80309
Tel: 303-735-5095; Fax: 303-492-7935
Web: http://anquetil.colorado.edu/szhong
________________________________________
From: cig-mc-bounces at geodynamics.org [cig-mc-bounces at geodynamics.org] On Behalf Of ting yang [heaventian at gmail.com]
Sent: Tuesday, January 22, 2013 5:07 AM
To: cig-mc at geodynamics.org
Subject: [CIG-MC] Reflective boundary condition in CitcomCU

Hi All,

In my understanding, reflective boundary condition means that Vn=0 at the boundary layer.
Here Vn means velocity normal to the boundary.

I noticed that in subroutine velocity_refl_vert_bc in Boundary_condition.c in CitcomCU, the reflective boundary condition is set by making Vx=0 and Szx=0 (taking x direction as an example):

if(E->parallel.me_loc[1] == 0)
                {
                    E->VB[1][node1] = 0.0;
                    if((ii != 1) && (ii != E->mesh.noz))
                        E->VB[3][node1] = 0.0;
                }

I wonder why it sets the reflective boundary condition like this.

How about commenting the lines about E->VB[3] or aading other lines like setting Syx=0, just like below?

if(E->parallel.me_loc[1] == 0)
                {
                    E->VB[1][node1] = 0.0;
                }

OR

if(E->parallel.me_loc[1] == 0)
                {
                    E->VB[1][node1] = 0.0;
                    if((ii != 1) && (ii != E->mesh.noz))
                        E->VB[3][node1] = 0.0;
                    if((XXXXXXXX) && (XXXXXXXX))
                        E->VB[2][node1] = 0.0;
                }

Thank you very much!
--
wish you happiness !
yours sincerely,
Yang Ting
School of Earth and Space Science
University of Science and Technology of China