regarding patch in two phase flow using VOF
 

hi all

iam doing simulation on oil-water flow..i want to enter the values of volume fraction of both the phases...so i adapted the region where i want to give the volume fraction.and then initialized the soln and then trying to patch using solve---->initialize---->patch..but in phase drop down list in patch window it is showing only oil and mixture as option and not the water..... does anyone know how do i do this.... thanks in advance rashmi

Re: regarding patch in two phase flow using VOF
 

Hi Rashmi,

To patch a water fraction of 1, you just need to patch an oil fraction of 0. Whatever your input is for the oil volume fraction, the water fraction will be 1 minus that fraction.

Regards,

John.

Re: regarding patch in two phase flow using VOF
 

Hi

When you have two phases, oil and water, then 1st initialize all the cells (the whole domain) with volume fraction of water=1 in the solution initialization window. And then select (using adaption window) the cells where you want oil, and initialize those cells with vf-oil=1 in the patch window.

In the patch window, you will find only mixture and secondary phases and not the primary phase. You can use mixture to initialize other values like pressure, velocity.. in the selected cells.

Regards

Manoj

Re: regarding patch in two phase flow using VOF
 

thanks manoj,

but whn u initialize the volume fraction in domain there also u dont have to key in the vf of water...there is also you hav enter the vf of oil...

i have to give vf of 0.2 to oil and .8 to water...can u expalin..

thanks rashmi

Re: regarding patch in two phase flow using VOF
 

Hi Rashmi

Do you want to initialize the whole domain with vf of oil=0.2 and vf of water=0.8 ? If so, then just initialize the cells with vf of oil=0.2 . This automitically ensures that your cells have vf of water=(1-vf of oil) i.e. 0.8

Good luck.

Manoj

Re: regarding patch in two phase flow using VOF
 

hi manoj,

cn u explain how do i initialize the whole domain..my mixture velocity is 2m/s...

so i adapted the region and did patch the vf of oil...cn it work....

one more thing is iam getting reversed flow in outflow...how do i avoid this...how to increase the domain size...plz explain

thank u very much

regards rashmi