[harry123]

Hi,

I wish to know under what requirements, a dirichlet boundary condition for pressure is implemented. I have mostly found literature dealing with neumann bc for pressure.

It would be of great help if anyone could point out some good read for getting an understanding on need and implementation of dirichlet bc for pressure.

I work with a FVM and SIMPLE algorithm.

Thank you,
Harry

[FMDenaro]

Originally Posted by harry123

Hi,

I wish to know under what requirements, a dirichlet boundary condition for pressure is implemented. I have mostly found literature dealing with neumann bc for pressure.

It would be of great help if anyone could point out some good read for getting an understanding on need and implementation of dirichlet bc for pressure.

I work with a FVM and SIMPLE algorithm.

Thank you,
Harry

Speaking about the elliptic pressure equation, for example, you can have a tank filled of fluid and a flow coming through outflow in some pressure-fixed environment.

[harry123]

Thanks for that...

Can you please suggest some literature that may help me in understanding how to actually implement this in the pressure poisson equation..?

[FMDenaro]

Originally Posted by harry123

Thanks for that...

Can you please suggest some literature that may help me in understanding how to actually implement this in the pressure poisson equation..?

http://onlinelibrary.wiley.com/doi/1...80905/abstract

[harry123]

Thank you very much..!!!

[leflix]

Originally Posted by harry123

Hi,

I work with a FVM and SIMPLE algorithm.

Harry

Pay attention that with SIMPLE you solve a kind of Poisson equation for the pressure correction not for the pressure itself.
The boundary conditions for this pressure correction equation is generally Neumann boundary condition on all boundaries.

[harry123]

Yes...and thats what confuses me...

If I wanted to explicitly specify the pressure value at a boundary (say 10 Pa), how do I incorporate that into the SIMPLE algorithm ?

Do I use the neumann condition for boundaries in pressure correction equation as usual and do something extra for this particular boundary ? Because, having an explicit pressure value means pressure correction is zero at that particular node ?

[leflix]

Originally Posted by harry123

Yes...and thats what confuses me...

If I wanted to explicitly specify the pressure value at a boundary (say 10 Pa), how do I incorporate that into the SIMPLE algorithm ?

Do I use the neumann condition for boundaries in pressure correction equation as usual and do something extra for this particular boundary ? Because, having an explicit pressure value means pressure correction is zero at that particular node ?

Yes Harry in this case I agree with you...I should do exactly as you suggest it. Zero for the pressure correction, which means Dirichlet boundary condition for the pressure correction with a zero value.
Generally on open boundary we rather prescribe velocity boundary condition rather than pressure, in this case Neumann BC for pressure correction is correct.

[skchoi]

Please read the following papers;

(1) S. R. Mathur and J. Y. Murthy, "Pressure Boundary Conditions for Incompressible Flow Using Unstructured Meshes" Numerical Heat Transfer, Part B, Vol. 32, pp. 283-298, 1997.

(2) K. M. Kelkar and D. Choudhury, "Numerical Method for The Prediction of Incompressible Flow and Heat Transfer in Domains with Specified Pressure Boundary Conditions", Numerical Heat Transfer, Part B, Vol. 38, pp. 15-36, 2000.