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-   -   Poisson Solver in STAR? (https://www.cfd-online.com/Forums/star-ccm/218250-poisson-solver-star.html)

PierceH June 13, 2019 15:18

Poisson Solver in STAR?
 
Are there anyways to solve a poisson equation in STAR, is there a built in solver or a way of tricking one into it using passive scalars or something similar?

I want to solve the following equation in order to resolve pressure:


laplacian(Pressure)=-rho*laplacian(0.5q.q)+grad(rho*q x omega)


If anyone has any experience with this it would be very helpful

ashokac7 June 18, 2019 02:17

Quote:

Originally Posted by PierceH (Post 736209)
Are there anyways to solve a poisson equation in STAR, is there a built in solver or a way of tricking one into it using passive scalars or something similar?

I want to solve the following equation in order to resolve pressure:


laplacian(Pressure)=-rho*laplacian(0.5q.q)+grad(rho*q x omega)


If anyone has any experience with this it would be very helpful


You could do this with User Codes. Please refer Star-CCM+ user guide for this. Poisson solver is already there in CCM in Electro-Magnitic field distribution. (Maxwell's equation of electrostatics) But electric potential is as a variable. So you can't use this for variable as Pressure.

Hope this helps.

PierceH June 18, 2019 08:59

Quote:

Originally Posted by ashokac7 (Post 736551)
You could do this with User Codes. Please refer Star-CCM+ user guide for this. Poisson solver is already there in CCM in Electro-Magnitic field distribution. (Maxwell's equation of electrostatics) But electric potential is as a variable. So you can't use this for variable as Pressure.

Hope this helps.

Ashokac,

Thanks for the advice. My logic was to follow passive scalars where in steady flow the transient term would settle to a 0 value and you could turn off the convection term leaving you with just diffusion and a source term. However, this equation is behaving as I would expect, setting the flow to laminar and Schmidt number to one if you multiply your source term by \mu then you should conceivably obtain a Poisson solver.


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