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Finding volume of bubbles

Posted 2021年7月31日 GMT+8 12:06 Computational Fluid Dynamics (CFD), Heat Transfer, Microfluidics 1 Reply

Niraj Sonule
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Hello everyone, I am simulating a problem which has two bubbles aligned vertically seperated by some distance. They both rise vertically up due to buoyancy. The domain is axi-symmetric and level-set method is used for solving the two-phase problem.

I want to calculate volume of the two bubbles (per radian) seperately.

Please help me doing so. Thank you in advance.

Niraj

1 Reply Last Post 2021年8月1日 GMT+8 17:34
Alexis Prel
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Posted: 3 years ago 2021年8月1日 GMT+8 17:34
Updated: 3 years ago 2021年8月2日 GMT+8 00:18

Hello Niraj,

In the model builder, for each bubble :

  • define a named selection
  • define a domain integration operator and sets its domain of application to the named selection you just created. Default names will be intop1 and intop2 but you may change it to something more explicit
  • create a variable volume_1 = intop1(2*pi*r)

Hence, you are integrating the function 2*pi*r where r denotes the radial coordinate of your axi-symmetric problem. Without the axial symmetry, you should integrate the constant function 1 instead. I would not be surprised to learn that COMSOL already takes care of the 2*pi*r factor for you, so you should check with a simple geometry (such as a cylinder) which of these two integrands gives the correct result.

Hello Niraj, In the model builder, for each bubble : * define a named selection * define a domain integration operator and sets its domain of application to the named selection you just created. Default names will be `intop1` and `intop2` but you may change it to something more explicit * create a variable `volume_1 = intop1(2*pi*r)` Hence, you are integrating the function `2*pi*r` where `r` denotes the radial coordinate of your axi-symmetric problem. Without the axial symmetry, you should integrate the constant function `1` instead. I would not be surprised to learn that COMSOL already takes care of the `2*pi*r` factor for you, so you should check with a simple geometry (such as a cylinder) which of these two integrands gives the correct result.

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