interFoam, dynamic contact angles and moving walls
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hi all,
i'm trying to simulate the wetting of a moving wall with dynamic contact angles. So as a very simple test case i made a vertical rectangular channel half filled with water and one wall moving. (see attached image) the boundaryconditions for the moving wall are: alpha.air: type dynamicAlphaContactAngle theta0 130; thetaA 110; thetaR 150; uTheta 1e-07; limit gradient; value nonuniform List<scalar> ... U type fixedValue value uniform (0.01 0 0); it seems to me - also looking at the code which i halfway understant - that for the calculation of the dynamic contact angle only the fluid velocity is used and not the relative velocity of the fluid with respect to the moving wall --> this results in a contact angle with the wall of 130° instead of 170° (the calculation of the contact angle in this BC are a bit odd) An error to report? or is there another way to choose the velocity BC? Attachment 73765 |
Probably you have already found a solution to this issue. If not, then I should mention that this is a known bug in the dynamic contact angle BC. You can read this bug report:
https://bugs.openfoam.org/print_all_...-1&show_flag=0 A possible fix has been suggested: Line 145 of dynamicAlphaContactAngleFvPatchScalarField is where the calculation is being done. Change this line to : Code:
return theta0_ * (1 - tanh(uwall/uTheta_) * sign(uwall/uTheta_) ) - thetaA_ * neg(uwall) * tanh(uwall/uTheta_) + thetaR_ * pos(uwall) * tanh(uwall/uTheta_); |
hi,
thanks for the reply and the suggested solution! no i haven't found a proper solution to the issue - i had to cheat quite a bit... (can you post the link to the bug report again, or the issue number? i cannot open it...) |
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How did you quantify the contact angle on the moving wall? I have a moving wall which pushes fluid so I have a moving line contact angle on the curved surface of the cylinder. i am assuming that assigning zeroGradient which ensures 90 degree contact angle results in wiggles when the liquid bulk rises due to the moving wall. Is there something which I can do?
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