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Having a problem with the use of Stationary Free Surface Feature to simulate an active Micor-Mixer

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"Hello, I am trying to simulate an active micro mixer using 'Rotating machinery, Laminar flow and 'Transport of Diluted Species'. In this study, I have a rotating circle (2D) in a 'T' shape channel with width of 50 micrometer. Also, I need to add the surface tension through the 'Stationary Free Surface' boundary to consider an interaction between this rotating circle and its environment. The value that I choose for surface tension is about 0.034 N/m and the flow inlet is about 400 micrometer/s. The problem is that at the last step of my simulation, the final concentration through the channel is 0.6 instead of 0.5! And this is totally weird, it is like a conservation law has been violated. Also, I checked it with choosing different values of rotation frequencies, from 0 to 10 rotation/sec but nothing changed and got the undesirable value for concentration. However, when I turn off the 'Stationary Free Surface', I get 0.5 finally, but this is not my original problem. I should have a surface tension in circle boundary. In other words, I want a hydrophilic object. Does anybody have an idea about this problem? Is there any other ways to make the mentioned circle hydrophilic?I have attached two pictures from my simulation. The one with the 0.6 value in end of channel is when I have the 'Stationary Free Surface' boundary condition."

Thank you for your patience and support.


0 Replies Last Post 4 juin 2017, 11:52 UTC−4
COMSOL Moderator

Hello Akbar Samadi

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