solve only transport equation and not Navier-Stokes

cosine · November 18, 2011, 06:05

Dear All,

I would like to know if it is possible to make a simulation modeling only the transport equation as an additional variable and not the flow equations.
More specifically, i would like to model the flow using a coarser mesh, and use this solution in the same domain with a very fine mesh to model the transport equation.
For example, COMSOL has this opportunity to store the flow solution, remesh and solve only the transport problem. Is this opportunity able to CFX?
Thank you very much.

NickFL · November 18, 2011, 14:58

Yes this can be done quite easily. Create two models the first being your coarse model where you solve the flow equations. Then create your fine model where you will solve the transport of your scalar. Set the Expert Parameters for Fluids and Turbulence (if applicable) to false in this finer model. When you go to the solver, specify your coarse solution results as the initial condition. These will interpolate the velocity distribution from your coarse mesh onto your fine mesh. Then you will not have to re-solve for the NS-equations.

cosine · November 19, 2011, 02:58

That's great! Thank you very much!

November 18, 2011, 06:05	solve only transport equation and not Navier-Stokes	#1
cosine Member Join Date: Apr 2009 Posts: 34 Rep Power: 17	Dear All, I would like to know if it is possible to make a simulation modeling only the transport equation as an additional variable and not the flow equations. More specifically, i would like to model the flow using a coarser mesh, and use this solution in the same domain with a very fine mesh to model the transport equation. For example, COMSOL has this opportunity to store the flow solution, remesh and solve only the transport problem. Is this opportunity able to CFX? Thank you very much.

November 18, 2011, 14:58		#2
NickFL Senior Member Join Date: Jun 2009 Location: Technische Universität Chemnitz Posts: 107 Rep Power: 16	Yes this can be done quite easily. Create two models the first being your coarse model where you solve the flow equations. Then create your fine model where you will solve the transport of your scalar. Set the Expert Parameters for Fluids and Turbulence (if applicable) to false in this finer model. When you go to the solver, specify your coarse solution results as the initial condition. These will interpolate the velocity distribution from your coarse mesh onto your fine mesh. Then you will not have to re-solve for the NS-equations. rockzh likes this.

November 19, 2011, 02:58		#3
cosine Member Join Date: Apr 2009 Posts: 34 Rep Power: 17	That's great! Thank you very much!