Weird Velocity Field for Capillary Flow in a Horizontal Tube

mashimaro_star · July 8, 2014, 20:23

Dear All,
I am new to use VOF to simulate Transient capillary flow. I tried to setup a simple 2D case for a water capillary flow in a horizontal tube (no gravity). Here are some setups:
(1) The contact angle is 60 degree, and the surface tension coefficient is 0.04 N/m.
(2) The liquid is set as the second phase and the air is the primary phase. I patched a region near the pressure inlet being filled with liquid.
(3) The time step is 1e-5 sec.

The volume fraction result seems ok. But, there are two problems make me feel that there is something not correct for my case:
(1) The interface seems wavy (please see figure 1). Anybody has the same problem? is this normal? Or this is due to some numerical inaccuracy?
(2) The Y-velocity field is weird for me. It seems that my calculation is wrong based on the Y-velocity contour (please see figure 2). If you know how to correct this, please let me know. Thank you very much in advance!!!

Yu

nurfatinas · December 15, 2014, 06:34

I couldn't load the pictures you had attached somehow but based on your statement I seem to have the same problem as you (or maybe not). Had you possibly resolved the issue? If yes I really hope to hear from you.

The picture is as attached.

Thanks.

July 8, 2014, 20:23	Weird Velocity Field for Capillary Flow in a Horizontal Tube	#1
mashimaro_star New Member yu feng Join Date: Jun 2010 Posts: 3 Rep Power: 16	Dear All, I am new to use VOF to simulate Transient capillary flow. I tried to setup a simple 2D case for a water capillary flow in a horizontal tube (no gravity). Here are some setups: (1) The contact angle is 60 degree, and the surface tension coefficient is 0.04 N/m. (2) The liquid is set as the second phase and the air is the primary phase. I patched a region near the pressure inlet being filled with liquid. (3) The time step is 1e-5 sec. The volume fraction result seems ok. But, there are two problems make me feel that there is something not correct for my case: (1) The interface seems wavy (please see figure 1). Anybody has the same problem? is this normal? Or this is due to some numerical inaccuracy? (2) The Y-velocity field is weird for me. It seems that my calculation is wrong based on the Y-velocity contour (please see figure 2). If you know how to correct this, please let me know. Thank you very much in advance!!! Yu

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December 15, 2014, 06:34		#2
nurfatinas New Member nurfatin Join Date: Dec 2014 Location: malaysia Posts: 6 Rep Power: 12	I couldn't load the pictures you had attached somehow but based on your statement I seem to have the same problem as you (or maybe not). Had you possibly resolved the issue? If yes I really hope to hear from you. The picture is as attached. Thanks.