Hello everybody!!

I am trying to do the DNS simulation for Impingind Jet on Falt Plate. A water Jet (in turbulence zone) is coming out of a circular Nozzle and impinges on a flat plate located at some height. Whole of the system (water jet and the flat plate) is enclosed in a cylindrical cell. So, there is no problem for the boundary condition of the fluid system(water + air)...it is no-slip B.C.

However, I am not so sure about how to deal with the air-water interface of the Jet. Off course, shape of the Jet varies with time and it is not known to us beforehand. It would be very nice if you people can suggest me something in this regard.

Thank you very much in anticipation!!

-chandra shekhar

take a look at the paper,

K. Yokoi, Feng Xiao, Mechanism of structure formation in circular hydraulic jumps: numerical studies of strongly deformed freesurface shallow flows, Physica D 161 (2002) 202–219.

I think that you should use a pressure boundary condition for the air-water interface. The shape of the jet may be evaluated iteratively. You can use body-fitted coordinates so that it is easy to apply the pressure boundary condition and also the computational domain will not change in the transformed coordinates even though the physical domian will change.

[natuan74]

Hi everybody,

i am using polyflow for simulating the impinging jet of fluid on a flat plate. I have a problem with boundary condition between fluid and air. it is very appreciated, if you, everybody, can help me the problem. Thank you

Nguyen Anh Tuan