Question on boundary conditions

July 27, 2004, 20:36

I'm using SIMPLE method and have a doubt on physical BC's.

For pressure, on has to make the gradient normal to the wall equal zero, but how to calculate the pressure of the fluid cell close to it?

In order to calculate the pressure of a cell (I'm using poisson) I'm supposed to use the values of pressure around the cell. Does it include boundary cells?

The problem is that I'm reaching very high pressure values close to the walls.

July 27, 2004, 22:26

refer to 'Numerical methods for Fluid flow and heat transfer' by Suhas V Patankar. The book explains the answer in great details...

July 28, 2004, 16:26

I'll look for that one. Thank you.

July 29, 2004, 13:17

1) To calculate the pressure values near the boundaries you should include the unknown boundary cells.

2) To treat boundary, you can have a look at the way it is done in FISHPACK which is an elliptic equation solver. http://www.scd.ucar.edu/css/software...ck/technote.ps

July 27, 2004, 20:36	Question on boundary conditions	#1
Diego Nogueira Guest Posts: n/a	I'm using SIMPLE method and have a doubt on physical BC's. For pressure, on has to make the gradient normal to the wall equal zero, but how to calculate the pressure of the fluid cell close to it? In order to calculate the pressure of a cell (I'm using poisson) I'm supposed to use the values of pressure around the cell. Does it include boundary cells? The problem is that I'm reaching very high pressure values close to the walls.

July 27, 2004, 22:26	Re: Question on boundary conditions	#2
centaur_ks Guest Posts: n/a	refer to 'Numerical methods for Fluid flow and heat transfer' by Suhas V Patankar. The book explains the answer in great details...

July 28, 2004, 16:26	Re: Question on boundary conditions	#3
Diego Nogueira Guest Posts: n/a	I'll look for that one. Thank you.

July 29, 2004, 13:17	Re: Question on boundary conditions	#4
agg Guest Posts: n/a	1) To calculate the pressure values near the boundaries you should include the unknown boundary cells. 2) To treat boundary, you can have a look at the way it is done in FISHPACK which is an elliptic equation solver. http://www.scd.ucar.edu/css/software...ck/technote.ps

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