L-shaped duct

sega · January 6, 2010, 08:34

Hello world.

I'm trying to simulate the flow in an L-shaped duct.
See the picture attached.

I'm using velocity-inlet and outflow as boundary conditions.
The rest are walls.

Unfortunately the case does not converge.
Residuals are stuck at some level.

On what does the convergence of such a case depend?
Any ideas?

Philipov · January 6, 2010, 09:42

First of all try to remesh the domain...as I see it is a bit of luck that you got constant residuals..... and.... I do not know the dimensions of the pipe, but..... outflow BC assumes fully developed flow... (for good results)

sega · January 6, 2010, 10:55

Quote:

Originally Posted by Philipov

First of all try to remesh the domain...as I see it is a bit of luck that you got constant residuals..... and.... I do not know the dimensions of the pipe, but..... outflow BC assumes fully developed flow... (for good results)

Remesh? I guess I should create a finer mesh?
Dimensions are 1m x 1m cross-section, with 10 meters overall-length.

Philipov · January 6, 2010, 12:46

yes, refine the mesh, take into account the inlet BC (velocity, Re, adequately calculate the equivalent diameter, fluid type and so on)...

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January 6, 2010, 09:42		#2
Philipov Senior Member Svetlin Filipov Join Date: Mar 2009 Location: United Kingdom Posts: 176 Rep Power: 17	First of all try to remesh the domain...as I see it is a bit of luck that you got constant residuals..... and.... I do not know the dimensions of the pipe, but..... outflow BC assumes fully developed flow... (for good results)

January 6, 2010, 12:46		#4
Philipov Senior Member Svetlin Filipov Join Date: Mar 2009 Location: United Kingdom Posts: 176 Rep Power: 17	yes, refine the mesh, take into account the inlet BC (velocity, Re, adequately calculate the equivalent diameter, fluid type and so on)...