Water Hammer simulation in Open Foam
 

Hi every one

I am going to simulate water hammer phenomenon in a pipe using open foam as a simple case. but I have problem to set the boundary conditions. has any one simulated this phenomenon before. I need to know the settings which is required.:confused:

thanks in advance.
Simin

Hello Dear simin
your question is too much general, you said:
whats your problem?
forexample do you know the velocity at inlet? if yes, then put your velocity fixedValue
or for wall is it no slip condition? then velocity would be zero and etc
so i think its better you make it clear where is the problem :)
However, if you want to find appropriate setting for your simulation, i suggest you to search in articles, then for those configuration, you can find similar BC at OpenFOAM

Hi nima

thank you for your reply.
I do not have problem for boundary conditions but in order to simulate the problem the density variation using the module of elasticity,K=dP/drho/rho, should be set to show the pressure change and compresibility. I simulate water hammer by fluent before using udf, but in open foam i do not know where I can set this change.
Hope I could explain my question clear. :)

first of All, as it a pressure shock, compressible flow u should use a compressible isothermal solver, which solver did you choose?

Hi Simin,
In the section 3.4 of the Programmers Guide you will find a tutorial of a water hammer simulation. The files of this tutorial can be found in the folder .../tutorials/compressible/sonicLiquidFoam.

I tried this tutorial some time ago and modified it to get the transient flow in a pipe resulting from the sudden opening of a valve. The pressure decrease was correct according to the Joukowski theory but instead of a sharp decrease of pressure there was a smooth profile that suggests there was strong false diffusion in the results. Were you able to get good results with fluent?

Best Regards,
Paulo