CFD Online Discussion Forums

CFD Online Discussion Forums (
-   FLUENT (
-   -   Open channel flow simulation using VOF (

rsaha September 11, 2012 17:40

Open channel flow simulation using VOF
1 Attachment(s)
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?


oinch October 2, 2012 08:16


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.


RodriguezFatz October 2, 2012 08:25

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?

rsaha October 5, 2012 14:14

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.

oinch October 8, 2012 02:15

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!

All times are GMT -4. The time now is 12:29.