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using groovy boundry condition in multiphase problom

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Old   November 30, 2011, 17:12
Default using groovy boundry condition in multiphase problom
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javad
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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?
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Old   November 30, 2011, 17:29
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Bernhard Gschaider
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Quote:
Originally Posted by javad814 View Post
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
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