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RyGuy July 27, 2009 14:12

Using ideal gas law and sutherland law in Fluent
Hello Fluent Users,

I am working on a project regarding the simulation of a process called Low Pressure Cold Spray (also known as Kinetic Spray). I am trying to analyze theoretically the single and multi-phase flow of the process and compare it with experimental data.

Therefore I have created my geometry in Gambit (simple 2d geometry of a convergent-divergent nozzle) and meshed the geometry with quad cells.

I have exported the mesh into Fluent and due to the nature of the process the procedure for setting up the simulation is as follows:

I defined the process using the density based implicit solver, 2D, Steady time enabling the energy equation for thermal considerations. I have selected the k-epsilon standard model and am only considering a single phase supersonic compressible flow. I am using an operating pressure of zero since mach number is greater than 0.1

I have found from literature that it would be ideal to consider the ideal-gas law for the material properties (air) and also the sutherland viscosity law for better accuracy in terms of compressibility and viscous effects.

My main inlet pressure and temperature ranges are 5-10 bars and 500-1000 K, respectively.

When I try to incorporate the ideal gas las for density of air and iterate to get a solution Fluent gives me an Error: floating point error and Error: Object () prompt.

How do I avoid this error? And, if anyone who fully understands Fluent can optimize my procedure for this process can you please provide your input?

Your replies are greatly anticipated....
Thanks in advance!


Chris D July 29, 2009 19:35

Have you tried this? (See 2.1.1)

I had a floating point error today, and reducing the Courant number solved the problem for me.

RyGuy July 30, 2009 10:04

Hello Chris,

Sorry I am new to this forum and have not been able to check out the FAQ.
I will give it a try and will keep you posted if it is successful or not.

Thanks for everything,

Tpozkar June 12, 2012 14:38

Hi RyGuy, I would like if you resolved your problem. I have a similar problem

Im trying to simulate a compressible flow in a gas turbine, and I get the following error:

Error: Internal error at line 1387 in file '..\..\src\rp_mstage.c'.
Divergence detected in AMG solver

I have tried the suggestions of the fluent_FAQ but Im not able to resolve my problem.


fuxiao_20 June 28, 2012 02:07

you can try intialize the flow field with a slow speed

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