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-   -   Triangular mesh - fully developed flow between parallel plate (https://www.cfd-online.com/Forums/main/82419-triangular-mesh-fully-developed-flow-between-parallel-plate.html)

 Amir_Ghasemi November 25, 2010 13:54

Triangular mesh - fully developed flow between parallel plate

Dear Friends,

I want to simulate a fully developed flow between infinite parallel plate (2-D), with prescribed pressure for inlet and outlet. When I use rectangular (structured) mesh, the results are consistent with analytical solution:

u = h ^ 2 (2 * mio) * ( Delta P / L) * ((y/h) ^ 2 - (y/a) )

but when I use 3-node triangular mesh (with any form I tested) the resulted velocity profile are not correct; lower velocity is obtained for a prescribed pressure gradient.

I tried finer triangular mesh, but no better results achieved.

I Use ADINA-8.5 Software which is finite element based.

Any suggestion and guidance is really appreciated.:)

 otd November 25, 2010 19:44

Should (y/a) in your formula be (y/a)^2 ?

 Amir_Ghasemi November 26, 2010 13:18

Thanks for your reply, it should be y/h, but this is not a mistake, there is a fundamental error in using triangular mesh, but I don't know what is that?

 Amir_Ghasemi November 28, 2010 05:52

Solved

I changed the upwind type from Finite Element to Finite Volume in ADINA and know the results are correct:).
It can be found here in ADINA:

Control -> Miscellaneous option -> Default upwinding type > Finite Element:)

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