vortex and high velocity order in VOF interface?

Qumars · January 10, 2016, 05:11

Dear colleagues
I am simulating a water flow in an oil media. size of cylinder and throat is .3 mm and .05 mm respectively.
In interface between water and oil, some vortexes occurs and velocity has high values,(inlet is 0.001 m/s but velocity is around 1 m/s in interface)
numerical schemes are, PISO,PRESTO, Quick and Geo-reconstruct
What is the reseaon?

mesh and v-countor has attached below
regards

LuckyTran · January 11, 2016, 16:12

It looks qualitatively reasonable.

The question is how much of the 1 m/s is explainable because of the difference in properties.

Do you have the right surface tension and wetting angle (and density obviously)?

Qumars · January 12, 2016, 05:05

dear Lucky Tran,
thanks for your reply,
actually this vortex haven't any effect on flow direction, but they reduce time step, because of courant number. it takes weeks to become steady.
it is interesting that i run the this model in openFoam and the highest velocity was .06 m/s. about ten time less than.
surface tension is .05 and contact angle is 30.
is there any solution?
best regard.

LuckyTran · January 12, 2016, 14:28

If no blatant errors then compare your discretization schemes (especially for the time-step). My guess there's limiters being activated for OF that isn't happening in Fluent.

January 12, 2016, 14:28		#4
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,845 Rep Power: 68	If no blatant errors then compare your discretization schemes (especially for the time-step). My guess there's limiters being activated for OF that isn't happening in Fluent. lourencosm likes this.

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January 11, 2016, 16:12		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,845 Rep Power: 68	It looks qualitatively reasonable. The question is how much of the 1 m/s is explainable because of the difference in properties. Do you have the right surface tension and wetting angle (and density obviously)?

January 12, 2016, 05:05		#3
Qumars New Member Qumars Join Date: Jan 2016 Posts: 2 Rep Power: 0	dear Lucky Tran, thanks for your reply, actually this vortex haven't any effect on flow direction, but they reduce time step, because of courant number. it takes weeks to become steady. it is interesting that i run the this model in openFoam and the highest velocity was .06 m/s. about ten time less than. surface tension is .05 and contact angle is 30. is there any solution? best regard.