Open channel flow simulation using VOF
 

Hi all,

I am simulating a 3d open channel flow. The model details are:

Steady, multiphase VOF, Realizable k-epsilon with enhanced wall treatment, the secondary phase is water and the primary phase is air.

The boundary conditions I am using are: mass flow inlet, pressure outlet with free surface specification and the top boundary is given pressure outlet condition.

The mass conservation is well satisfied after the simulation. I have plotted the free surface profile and there exist an spike near the inlet boundary. Please see the attached picture. I have simulated a 2D channel with same boundary conditions and the free surface profile looks good. Probably it is arising because of the effect of side walls. Do you think there might be some other factors responsible for this? like mesh, turbulence parameters etc?

Thanks.

hello,

I am trying to do the same thing as you but I don't really know how to do ... Is it necessary to define a USER DEFINE FUNCTION for this case ?

thanks for answering.

Samia

Hi rsaha,

Did you solve your problem? Looks like some numerical artifact to me. Any problems with the mesh? Isn't your boundary condition "water fraction = 0" above the black line of the mass flow inlet? How can there be any water?

Hi, RodriguezFatz, I found that there was some problem with the mesh. Now it is not showing any spike.

@Oinch, it is not necessary to define a UDF for what I am doing.

Thanks for answering rsaha,

Did you use the table profile and assign one to a zone? like volume fraction air?

Where in fluent do you say that above is air and down is water ? is it when you mesh ?

Thanks for helping me!

El fenómeno de la ondulación en la entrada se debe al flujo gradualmente variado en transición cuando el flujo es subcritico