# Water fountain from a vertical pipe inside another water body with lesser density

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 March 25, 2020, 12:10 Water fountain from a vertical pipe inside another water body with lesser density #1 New Member   Ahsan Join Date: Nov 2019 Location: Bologna, Italy Posts: 27 Rep Power: 6 Hello Fellows, I am doing a master thesis in Italy and I need to simulate a case in OpenFOAM. The case is of a vertical pipe nozzle (that ejects water like an underwater volcano, just to explain), while the outlet of the nozzle pipe is actually immersed inside another water body of lesser density. I am not able to find any tutorial that can simulate this condition. I guess it is a multiphase problem (since there are two fluids of different densities). I am new to OpenFOAM, although I know how to create blockMesh and also familiar with snappyHexMesh. I am planning to create STL file for the pipe and import it into the blockMesh using snappyHexMesh. But how can I simulate this particular condition? How can I describe one end of the pipe as inlet and other as the outlet while the outlet part is 20 cm under the water? Please help me Thank you, people!

 March 26, 2020, 04:14 #2 Senior Member   Alexey Matveichev Join Date: Aug 2011 Location: Nancy, France Posts: 1,930 Rep Power: 38 Hi, You just need inlet patch (which is created by snappyHexMesh). Outlet of the tube is inside simulation domain, so there is no boundary conditions there. You can adapt almost any interFoam tutorial to your case.

March 29, 2020, 12:33
#3
New Member

Ahsan
Join Date: Nov 2019
Location: Bologna, Italy
Posts: 27
Rep Power: 6
Quote:
 Originally Posted by alexeym Hi, You just need inlet patch (which is created by snappyHexMesh). Outlet of the tube is inside simulation domain, so there is no boundary conditions there. You can adapt almost any interFoam tutorial to your case.
Thank you so much alexeym for the response. I have made the geometry(inlet, pipe, tank, everything), I even used setFieldsDict to set my fluids in the domain.
But when the simulation goes on, I see that the velocity U is coming out from the pipe into the tank, but the fluids are not mixing at all, I mean I don't understand which fluid's velocity is this.

I am using interMixingFoam in 3D. The inlet is at the bottom center of the tank.
I have uploaded my simulation photos, showing heavy and light water at 0.125 seconds, as well as velocity at times 0, 0.025 and 0.125 seconds.
Attached Images
 1.png (13.6 KB, 22 views) 2.png (10.5 KB, 17 views) 3.png (16.3 KB, 16 views) 4.png (20.5 KB, 17 views) 5.png (22.4 KB, 15 views)

 March 29, 2020, 12:42 #4 New Member   Ahsan Join Date: Nov 2019 Location: Bologna, Italy Posts: 27 Rep Power: 6 My heavy water is not coming out of the pipe into the tank to be mixed with the lighter water

 March 29, 2020, 16:52 #5 Senior Member   Alexey Matveichev Join Date: Aug 2011 Location: Nancy, France Posts: 1,930 Rep Power: 38 Hi, From attached figures it is difficult to say if your geometry/mesh/boundary conditions are correct. Could you post mesh coloured by patch IDs? Could you post checkMesh output?

April 4, 2020, 07:26
#6
New Member

Ahsan
Join Date: Nov 2019
Location: Bologna, Italy
Posts: 27
Rep Power: 6
Quote:
 Originally Posted by alexeym Hi, From attached figures it is difficult to say if your geometry/mesh/boundary conditions are correct. Could you post mesh coloured by patch IDs? Could you post checkMesh output?
Dear Alexeym, Thank you so much for your help. As you suggested about the inlet condition, I tried to work on that. The problem was that I was using a wrong velocity condition for my inlet.

I used flowRateInletVelocity now and everything works fine.

 Tags fountain, nozzle, pipe, underwater pipe