Few simple questions concerning boundary conditions (pressure)

milos · March 20, 2009, 12:01

I'm new to OpenFOAM and I have a few fairly simple questions concerning boundary conditions. I am using 'simpleFoam' solver with RNGk-epsilon model.

1. - What is the default unit for pressure in OpenFOAM? In the small matrix it stands
[0 2 -2 0 0 0 0], which would basically mean [m^2/s^2]. What sort of pressure unit is that? I tried changing it to [kg/(m*s^2)] = [Pa], but then OpenFOAM doesn't run.

2. - I would like to measure pressure losses due a pipe elbow, but I'm not sure which boundary conditions to use for for pressure at the inlet and outlet. Currently I'm using 'zeroGradient' for inlet and 'fixedValue' (uniform 0) for the outlet. Any advice is welcome.

Thanx a million!

Milos

milos · March 21, 2009, 08:08

Ok, I found the answer to my first question, but I could still use some advice for the other one.

Thnx

Milos

March 20, 2009, 12:01	Few simple questions concerning boundary conditions (pressure)	#1
milos New Member Milos Stanic Join Date: Mar 2009 Location: Novi Sad, Serbia Posts: 29 Rep Power: 17	I'm new to OpenFOAM and I have a few fairly simple questions concerning boundary conditions. I am using 'simpleFoam' solver with RNGk-epsilon model. 1. - What is the default unit for pressure in OpenFOAM? In the small matrix it stands [0 2 -2 0 0 0 0], which would basically mean [m^2/s^2]. What sort of pressure unit is that? I tried changing it to [kg/(m*s^2)] = [Pa], but then OpenFOAM doesn't run. 2. - I would like to measure pressure losses due a pipe elbow, but I'm not sure which boundary conditions to use for for pressure at the inlet and outlet. Currently I'm using 'zeroGradient' for inlet and 'fixedValue' (uniform 0) for the outlet. Any advice is welcome. Thanx a million! Milos

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March 21, 2009, 08:08		#2
milos New Member Milos Stanic Join Date: Mar 2009 Location: Novi Sad, Serbia Posts: 29 Rep Power: 17	Ok, I found the answer to my first question, but I could still use some advice for the other one. Thnx Milos