|July 14, 2011, 11:03||
How to prevent backflow when airfoil starts heaving
Join Date: Mar 2009
Posts: 125Rep Power: 9
I am trying to simulate an airfoil doing pure heaving, up and down.
My udf is:
/* Compiled udf for modelling plunging airfoil in Fluent*/
The equation of the plunging motion y(t)=amp*sin(2*pi*f*t)
amp = plunge amplitude
f = plunge frequency
real k = 0.58;
real amp = 0.175;
real Uinf = 1.;
freq = 0.58;
omega = 2.0*M_PI*freq;
/*get the thread pointer for which the motion is defined*/
vel = omega*amp*cos(omega*time);
Message("vel %f time %f k %f h %f\n",cg_vel,time,k,amp);
The BC at outlet is simply outflow or pressure outlet.
My initial simulation was at Re=10000. All went fine.
However, when I tried to simulate at Re=100, backflow happens, after about 200 timesteps. Tried to reduce the time interval but it still happens.
What can I do to prevent this from happening?
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|how to prevent backflow?||May Lim||FLUENT||2||June 20, 2007 12:17|
|Extreme large coefficient for heaving airfoil||Ben||Main CFD Forum||1||December 29, 2006 22:58|
|Heaving airfoil??||quarkz||Main CFD Forum||4||January 12, 2006 14:06|