# Poisson Solver in STAR?

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 June 13, 2019, 15:18 Poisson Solver in STAR? #1 Member   Pierce Join Date: May 2019 Posts: 40 Rep Power: 7 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

June 18, 2019, 02:17
#2
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Ashok Chaudhari
Join Date: Aug 2016
Location: Pune, India
Posts: 260
Rep Power: 10
Quote:
 Originally Posted by PierceH 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.

June 18, 2019, 08:59
#3
Member

Pierce
Join Date: May 2019
Posts: 40
Rep Power: 7
Quote:
 Originally Posted by ashokac7 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.

 Tags passive scalar, pde, poisson equation, solve pressure