[horror]

Hello everybody,

I'm trying to model a structure like this one: https://postimg.cc/7fzKCj1X

It's a succession of stilling pools, which have the same geometry (depth, width and lenght), so the water is expected to flow creating and hydraulic jump in these pools and then get the critical depth in the succesive weirs and so on. Something like this: https://postimg.cc/zLCq7JmB

The idea is to get an uniform flow behaviour since the geometry is the same in every pool.

I've created a model with the following characteristics:

• Initial mesh size: 0,10 m
• Turbulence model: RNG k-e
• BC upstream: Volume flow rate with critical depth (fluid elevation)
• BC downstream and upper face: pressure 0 Pa
• BC in sides: symmetry
• Momentum advection: Second order monotonicity preserving

The results show a weird behaviour, even with a finer mesh of 0,05 m. The flow is not attaching to the weirs and gets projected: https://postimg.cc/MM29YS79

So I decided to include the air entrainment model with dispersed multiphase flow, variable density flow and dynamic void pressure, since this structure creates a highly aireated flow.

These are the results I'm getting with a 1 meter width model: https://postimg.cc/7bCLzrBF

The pools get filled and the flow doesn't project like in the non-air model, but it behaves non-uniformly and there are some quite strange splashes.

I've also tried k-omega and LES model turbulence but I dont' get the results I was expecting either.

Does anybody have any hint about what I'm doing wrong in this model?


Thank you very much for your time and help.