Parasitic currents in VOF

josephmp · January 10, 2016, 02:00

hi friends,

i am trying to simulate two phase gas-liquid flow in microchannels using Explicit VOF in ANSYS FLUENT. On the gas-liquid interface some un-physical velocities(parasitic currents) are developing, especially where the interface meets the channel wall. These velocities are large enough to alter the expected flow nature. How can I eliminate these velocities?

my settings are,

1.CSF model for- surface tension modelling(interestingly the parasitic velocity direction is reversing when CSS model is used)
2.numerical schemes are, PISO,PRESTO, second order upwind and Geo-reconstruct

plz help........

silent2608 · February 4, 2016, 11:52

unfortunately inherent to CSF model, read the theory behind it for clarity

http://www.ann.jussieu.fr/frey/paper...%20tension.pdf

I'm not quite sure myself how to address this issue or how to lower its effect. If you manage to find answers please report.

are you using explicit scheme? I would assume explicit vof with courant ~< 0.7 might help

alanzago · February 10, 2016, 16:23

Hi,
I think you can try to used the compressive scheme. Using with your setup and a good mesh the parasitic currents will be reduzed

January 10, 2016, 02:00	Parasitic currents in VOF	#1
josephmp Member joseph Join Date: Jan 2015 Posts: 32 Rep Power: 11	hi friends, i am trying to simulate two phase gas-liquid flow in microchannels using Explicit VOF in ANSYS FLUENT. On the gas-liquid interface some un-physical velocities(parasitic currents) are developing, especially where the interface meets the channel wall. These velocities are large enough to alter the expected flow nature. How can I eliminate these velocities? my settings are, 1.CSF model for- surface tension modelling(interestingly the parasitic velocity direction is reversing when CSS model is used) 2.numerical schemes are, PISO,PRESTO, second order upwind and Geo-reconstruct plz help........

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February 4, 2016, 11:52		#2
silent2608 New Member Join Date: Nov 2015 Posts: 17 Rep Power: 11	unfortunately inherent to CSF model, read the theory behind it for clarity http://www.ann.jussieu.fr/frey/paper...%20tension.pdf I'm not quite sure myself how to address this issue or how to lower its effect. If you manage to find answers please report. are you using explicit scheme? I would assume explicit vof with courant ~< 0.7 might help

February 10, 2016, 16:23		#3
alanzago New Member Alan Zago de Souza Join Date: Oct 2014 Location: Florianópolis - Brazil Posts: 5 Rep Power: 12	Hi, I think you can try to used the compressive scheme. Using with your setup and a good mesh the parasitic currents will be reduzed