Hi, I'm trying to simulate the Marangoni convection caused by the presence of a bubble situated on a heated surface, but I'm having many problems. Firstly, how should I try to model this? Should I use two domains, one for air and one for my liquid, or should I represent the bubble by a volume fraction? I need to specify a fluid pair to have the surface tension option become available, but how can you specify a varying surface tension (one that varies with temperature)? I have tied a simple linear variance, but get an error stating I need some prefix for phase or particle.

Any help will be greatly appreciated,

Seamus

Have you successfully validated a bubble free maragoni convection simulation?

Do you mean a free-surface model? I have not been able to specify a varying surface tension coefficient, so I can't include Marangoni forces,

I should use one domain and a volume fraction for the bubble. However, I doubt if CFX can do the job. You need to know that surface tension is implemented explicitly and that you need a very fine mesh. Therefore you will need a lot of iterations and a very small timestep.

Perhaps you could consider Fluent or Star CD with a VOF method. Or an academic tool specifically created for this type of problem?

Good luck, Gert-Jan

www.bunova.nl

I dont think CFX even has a facility for varying the ST coef.

In the modelling notes it says the Marangoni force will be automatically included if the surface tension is variable. I have asked for technical support from CFX but am yet to get any feedback.

Have you successfully validated a bubble free maragoni convection simulation?