[swak4Foam] using groovy boundry condition in multiphase problom

 Register Blogs Members List Search Today's Posts Mark Forums Read

November 30, 2011, 16:12
using groovy boundry condition in multiphase problom
#1
New Member

Join Date: Aug 2010
Posts: 22
Rep Power: 13
Hi every body
I have 2D open channel and want to defined a groovy condition in inlet and just for water (when alpha=1)
this is my velocity profile

[ type groovyBC;
value uniform (0 0 0);

valueExpression
"((pos().y-y0)<=(A*cos(-w*time()+pi/2.0)+0.5*k*A*A*cos(2*(-w*time())+pi))) ? 1*A*w*pos().y/y0*vector( cos(-w*time()+pi/2), sin(-w*time()+pi/2), 0) : vector(0,0,0)";]

with this profile the effect of an air is above the water is similar a wind that i dont want it is it possible to change velocity profile or other things to defined the velocity profile just for alpha=1?
Attached Images
 Screenshot.png (961 Bytes, 8 views) Screenshot-2.png (16.8 KB, 14 views) Screenshot-3.png (6.0 KB, 13 views)

November 30, 2011, 16:29
#2
Assistant Moderator

Bernhard Gschaider
Join Date: Mar 2009
Posts: 4,212
Rep Power: 49
Quote:
 Originally Posted by javad814 Hi every body I have 2D open channel and want to defined a groovy condition in inlet and just for water (when alpha=1) this is my velocity profile [ type groovyBC; value uniform (0 0 0); valueExpression "((pos().y-y0)<=(A*cos(-w*time()+pi/2.0)+0.5*k*A*A*cos(2*(-w*time())+pi))) ? 1*A*w*pos().y/y0*vector( cos(-w*time()+pi/2), sin(-w*time()+pi/2), 0) : vector(0,0,0)";] with this profile the effect of an air is above the water is similar a wind that i dont want it is it possible to change velocity profile or other things to defined the velocity profile just for alpha=1?
Took me some time to understand your question. Basically you want above the waterline a zeroGradient for the velocity? That is possible as groovyBC is derived from the mixed boundary condition (look it up in the User Guide).

fractionExpression "alpha1>0.5";

or something similar should do the trick