calculate bubble velocity
hi former
i guess, it should be possible to access a bubble velocity with swak4Foam but i dont know how the procedure can be? the procedure should be like that: 1) select all cells with alpha < 0.5 2) calculate the gravity center in each time step any comment or suggestion? |
Quote:
"(pos()*vol()*(1-alpha1))/sum(vol()*(1-alpha1))" (with an accumulation sum) might give you the center of the "non-fluid".Have a look at my presentation from the last workshop (you'll find it on the swak4Foam-page on the Wiki). Slide 76 has a similar application. BTW: if you're interested in the velocity of the liquid interface then you might want to have a look at slide 155 where it s demonstrated how to calculate that with sampledSurfaces |
Hi Foamers,
I'm doing a 3D simulation of two and three bubble rising using a modified interFoam solver and I need to bubbles centre position, velocity and surface area. For a single bubble rising I used swak4Foam expressions for example for bubble centre position in Y as follows : Code:
bubbleCentreY Thanks in advance, Best Regards, Arsalan. |
1 Attachment(s)
Hello all,
Thank you for the info you provided here. I would be appreciative if you let me know your opinion. (I have attached my case) I am also working on the terminal velocity of bubbles. Using the paraView, I measure the center of a bubble location in two successive time steps, then by deviding the displacement of the center of bubble to the time difference, I want to calculate the velocity. The problem is, the value that I gain is 50% lower than the reported values in the literature. I am using a 2D mesh in openFoam 8 using interFoam. The contents of my 0 folder are: U file: dimensions [0 1 -1 0 0 0 0]; internalField uniform (0 0 0); boundaryField { bottom { type noSlip; } outlet { type noSlip; } walls { type slip; } defaultFaces { type empty; } } p_rgh file: dimensions [1 -1 -2 0 0 0 0]; internalField uniform 0; boundaryField { bottom { type zeroGradient; } outlet { type zeroGradient; } walls { type zeroGradient; } defaultFaces { type empty; } } alpha file: dimensions [0 0 0 0 0 0 0]; internalField uniform 0; boundaryField { bottom { type zeroGradient; } outlet { type zeroGradient; } walls { type zeroGradient; } defaultFaces { type empty; } } transportProperties file: phases (air water); air { transportModel Newtonian; nu nu [ 0 2 -1 0 0 0 0 ] 1.5E-5; rho rho [ 1 -3 0 0 0 0 0 ] 1.18; } water { transportModel Newtonian; nu nu [ 0 2 -1 0 0 0 0 ] 7.22E-7; rho rho [ 1 -3 0 0 0 0 0 ] 995.7; } Thanks a lot. |
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