dispersion with radial velocity

CharlineF · September 10, 2019, 14:55

Dear OpenFoam users,

I'm trying to simulate the dispersion of a plume with an initial radial velocity of around 10 m/s (the plume is expanding in all the directions).

I'm working in incompressible with pimpleFoam and I've set a concentration scalar (dye), as I would have set temperature.
Would you know how I can set the initial velocity of the plume?

I've tried to use funkySetField but it does not work at all (it works well for a vertical initial velocity but fails when I set a radial velocity - it might be due to the fact that I try to expand something that cannot be expanded in incompressible because a negative pressure appears in the center of the plume and stop the dispersion).
I've also tried to set a concentration source, as well as a velocity source or a pressure source. But it's not working neither, I don't succeed to give the initial "push".

Does someone have an idea about how to solve the problem? It would be a great help to me.

Thank you very much in advance,
Charline

CharlineF · September 12, 2019, 14:16

no idea ?

raumpolizei · September 13, 2019, 02:59

Just a weird idea: Maybe you could create a spherical mesh (computational domain = space between two spheres) and set the velocity normal to the inner boundary to be 10 m/s. I think the pressure could then adapt. In 2D it would be a circle in a circle.

CharlineF · September 13, 2019, 12:24

Quote:

Originally Posted by raumpolizei

Just a weird idea: Maybe you could create a spherical mesh (computational domain = space between two spheres) and set the velocity normal to the inner boundary to be 10 m/s. I think the pressure could then adapt. In 2D it would be a circle in a circle.

Hi Raumpolizei,
Thank you for your reply. I will have a try ! I'm running out of ideas right now so thank you

September 10, 2019, 14:55	dispersion with radial velocity	#1
CharlineF New Member Join Date: Sep 2019 Posts: 3 Rep Power: 6	Dear OpenFoam users, I'm trying to simulate the dispersion of a plume with an initial radial velocity of around 10 m/s (the plume is expanding in all the directions). I'm working in incompressible with pimpleFoam and I've set a concentration scalar (dye), as I would have set temperature. Would you know how I can set the initial velocity of the plume? I've tried to use funkySetField but it does not work at all (it works well for a vertical initial velocity but fails when I set a radial velocity - it might be due to the fact that I try to expand something that cannot be expanded in incompressible because a negative pressure appears in the center of the plume and stop the dispersion). I've also tried to set a concentration source, as well as a velocity source or a pressure source. But it's not working neither, I don't succeed to give the initial "push". Does someone have an idea about how to solve the problem? It would be a great help to me. Thank you very much in advance, Charline

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September 12, 2019, 14:16		#2
CharlineF New Member Join Date: Sep 2019 Posts: 3 Rep Power: 6	no idea ?

September 13, 2019, 02:59		#3
raumpolizei Member Join Date: Dec 2018 Location: Darmstadt, Germany Posts: 87 Rep Power: 7	Just a weird idea: Maybe you could create a spherical mesh (computational domain = space between two spheres) and set the velocity normal to the inner boundary to be 10 m/s. I think the pressure could then adapt. In 2D it would be a circle in a circle.