Learning Forum

[Patrick Kirby]

Hello All,

My question involves a mixing tank once again. In this case I recieve an error message indicating a floating point error after increasing the inflow through a sparger located near the bottom of the tank. All other settings similar, when the sparging rate is increased a floating point error occurs. I attempted to initialize the flowfield with the solution at the lesser sparging rate and also decreased the time step for the transient solver, but niether of these ideas worked. I am thinking that the mesh could be an issue, but the parameters describing the mesh seem acceptable. 

Thanks for reading my post

[SRP]

Hi,

Can you please share statistics of your mesh? 

Since floating point error occurs mainly due to the mesh.

Thank you.

[Patrick Kirby]

 

Hi SRP, I have two regions, one stationary and one moving making use of a sliding mesh. The associated mesh statistics are as follows:

Min Ortho quality: 0.11

Max Aspect Ratio: 21.0, a bit large and likely due to small sparging elements at the base of the geometry.

Thanks

 

 

[Patrick Kirby]

I reworked my mesh a bit and I got things to run a bit longer, but still experienced a bit of a blow up. I'm using RSM (w/ scalable wall functions and a moving mesh) to model turbululence and the Eulerian-Eulerian mutliphase model. I actually had a bit of luck running the simulation as a mixture for mutliphase, but the outlet pressure boundary condition led to a build-up of gas.