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kantipudi March 18, 2008 15:20

simple pipe problem
Hi everyone,

I am trying to model flow through a simple pipe. Whatever boundary conditions I take, the velocity contours are the same. There is maximum velocity at inlet, then decreases a bit further and finally shows zero allover the pipe. Not only pipe, whichever geometry I take, the velocity contours are same. I don't know why this is happening.

Please help me in this case as I am unable to move further from here.

Thank you. rohini

Ahmed March 19, 2008 00:35

Re: simple pipe problem
Are you specifying correct BC, it sounds as if there is no flow outlet

kantipudi April 7, 2008 14:30

Re: simple pipe problem

For a 3-D model, for eg: there is a flow in a pipe or some other structure and there is an obstruction inside the pipe , is there any special method to design it?

Method I followed : (solved for velocity profiles)

1. In Gambit, create a face, sweep the face so that it forms a volume1.

2. create an edge, copy the edge along the width of the volume, make a face and then sweep it to form a volume2 (which is the obstruction inside volume1).

3. mesh the edges first, faces next and then the volumes 1&2.

4. Define inlet (mass flow inlet) and outlet (outflow) BCs only as the wall and the continuum entities are default.

volume2 is also a wall as there should be no flow through the wall.

5. export the file, read it in Fluent, grid check, K-e turbulence model.

6. mass flow rate at inlet assigned. Material is air.

7. roughness constant,roughness height, k, epsilon are the same default values. No changes are made.

8. solve it.

If I follow this method,

a. I am missing the borders of the model. b. The flow is straight away, as if the obstruction doesn't exist.

Is this the method to run the model? Please suggest me the procedure if I am wrong somewhere. Please help me as I need this to be working.

Thank you. rohini.

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