[Amirreza_pro]

Hi guys.
We are using our data for a simulation in Fluent.
Our Data are for:
1- Cp
2- Viscosity
3- Lambda
4- Density
As you know, The user-defined real gas model (UDRGM) has been developed to allow you to write your own custom real gas model to fit your particular modeling needs.
The point is that, when we use our data for
1- Cp
2- Viscosity
3- Lambda
and we use this formulation for density according to Redlich-Kwong Equation of State for Real Gas Modeling:

we do not have any problem and our solution will converge.
But when we use our data for density and use this:
double Air_density(cell_t cell, Thread *thread, cxboolean vapor_phase, double temp, double density, double press, double yi[])
{
real mix = 0;
return CalcGasAblation(&rhoA, &rhoB, &rhoC, &rhoD, &rhoMixPoints, &rhoPressPoints, &rhoTempPoints, rhoNumMixPoints, rhoNumPressPoints, rhoNumTempPoints, mix, Air_pressure(temp, density), temp, rhoEquidistant);

In this case we are using interpolation function for our data of density.
the solution would diverge as you see in this picture
[IMG][/IMG]


That means we only can not use our data for density (our interpolation function for density).

In attachment you can find codes for converged and diverged codes.
our data for density you can download with this link:
https://we.tl/t-aSC30jrbtP

Can anyone please help me and say where is the problem? I really stuck in this problem.
Thanks in advance