Hi,

I am running a simulation of a 3D geometry with air at constant density and it works very fine.

Now I changed the air properties to ideal gas (there are up to 3 bars pressure on my device). When I start iterating, the floating point error occurs. Even when I set courant number to 0.1 and at the mass flow inlet boundary ant pressure outlet boundary all turbulence values to 0.1 (k-epsilon) the floating point error occurs before the first iteration is finished.

What is wrong? Any help is highly appreciated!

Ralf

I am not sure but it may be due to bad input/initialization. Since you said that error occurs before the first iteration is over, it indicates to some problem with your input data.

Swarup.

thanks for your answer! My input (inlet into the geometrie) is just a constant mass flow rate normal to boundary. That works fine for the constant density simulation. Or what kind of input do you maen?

Ralf

I mean inputs other than boundary data like those in initialization, property data, etc.

Hi

I had a similar problem with the initialization but when I initialized my model, appeared both, a pressure limited and viscosity limited on all cells before I began the iteration process. What can I do?

Alex

answer to this problem can be found in the User-Guide. if you see the message viscosity limited to ----- in ---cells and pressure limited to--- in ---- cells, then it has something to do with your problem set-up. your variables of interest reach the maximum/minimum limit set to prevent solver from crashing. FLUENT user guide tell that you should review your problem set-up with respect to type and quality of grid, appropriate boundary conditions, etc.

Swarup.