|
[Sponsors] |
June 17, 2011, 16:12 |
2D synthetic jet
|
#1 |
New Member
jerome
Join Date: May 2011
Posts: 4
Rep Power: 15 |
hi everyone,
I really need your help. Well, i've got this equation : F = Fx*10000*exp(-((x - x0 - y + y0)/y)² − betax*(y − y0)²) i + Fy*10000*exp(-((x − x0)/y)² - betay*(y − y0)²) j My geometry is a simple rectangle : (-10,0);(-10,10);(10,10);(10,0) dimensions in mm. All the edge are wall. I try to create a 2D jet centre in (0,0). So i've created 2 forces which are symetric. The distance between the 2 forces is 12mm. That's my UDF : #include "udf.h" DEFINE_SOURCE(force_1_x,c,t,dS,eqn) { real x[ND_ND]; real source; real fx0,x0,y0,betax; fx0=2.6; x0=-0.004; y0=0.001; betax=800000; C_CENTROID(x,c,t); source =fx0*10000*exp(-((x[0]-x0-x[1]+y0)/x[1])*((x[0]-x0-x[1]+y0)/x[1])-betax*(x[1]-y0)*(x[1]-y0)); dS[eqn]=0; return source; } DEFINE_SOURCE(force_1_y,c,t,dS,eqn) { real x[ND_ND]; real source; real fy0,x0,y0,betay; fy0=2; x0=-0.004; y0=0.001; betay=10000000; C_CENTROID(x,c,t); source =fy0*10000*exp(-((x[0]-x0)/x[1])*((x[0]-x0)/x[1])-betay*(x[1]-y0)*(x[1]-y0)); dS[eqn]=0; return source; } DEFINE_SOURCE(force_2_x,c,t,dS,eqn) { real x[ND_ND]; real source; real fx0,phi,x0,y0,betax; fx0=2.6; x0=0.006; y0=0.001; betax=800000; C_CENTROID(x,c,t); source =-fx0*10000*exp(-((x[0]-x0-x[1]+y0)/x[1])*((x[0]-x0-x[1]+y0)/x[1])-betax*(x[1]-y0)*(x[1]-y0)); dS[eqn]=0; return source; } DEFINE_SOURCE(force_2_y,c,t,dS,eqn) { real x[ND_ND]; real source; real fy0,phi,x0,y0,betay; fy0=2; x0=0.006; y0=0.001; betay=10000000; C_CENTROID(x,c,t); source =fy0*10000*exp(-((x[0]-x0)/x[1])*((x[0]-x0)/x[1])-betay*(x[1]-y0)*(x[1]-y0)); dS[eqn]=0; return source; } So as you can see, the only difference is a minus in the force_2_x. The problem is that i don t observe a symetric jet. So to try to understand the problem, i've observe the result give by fluent when there is just the force 1 and when there is just the force 2. The result are not symetric. For example, with the force 1 i've a max velocity mag of 5.55m/s with the force 2 this value is about 5.75m/s Anyone have an idea to resolve this problem or just to explain me why i've obtain such result. Thanks, Jerome |
|
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
suction boundary condition for a synthetic jet | morteza08 | FLUENT | 0 | August 18, 2010 08:48 |
UDF for synthetic jet simulation | Chicken | Fluent UDF and Scheme Programming | 5 | March 18, 2010 06:44 |
Synthetic (pulsatile) jet transient simulation | aero | CFX | 0 | November 6, 2009 02:10 |
inclined synthetic jet | Marouane Dghim | Main CFD Forum | 0 | July 15, 2008 10:41 |
synthetic jet velocity amplitude | adnen | Main CFD Forum | 1 | June 9, 2008 17:56 |