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Old   March 26, 2006, 06:55
Default DEFINE_CG_MOTION
  #1
s
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Hi,

I have a model with two moving valves. I'm using one define_cg_motion macro for each valve. The problem is that only one valve moves like it should and that is the valve which is defined in the last define_CG_motion. I have tried to change the order of the two macroes, but it is always the valve which is defiend in the last macro which moves...

How does I solve this problem? Is there any other way than using two separate define_cg_motion macroes? Can I put both into one and how?

S
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Old   April 5, 2006, 04:30
Default Re: DEFINE_CG_MOTION
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Jura
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Hi, try anything like this (it should help): #include "udf.h" DEFINE_CG_MOTION(valve1, dt, velocity, omega, time, dtime) { if (!Data_Valid_P()) {

Message("Pas bon du tout!\n");

return; }

NV_S(velocity, =, 0.0); NV_S(omega, =, 0.0);

/*movement of the body*/ vel[1]=...; omega[2]=...;

Message("\n moving valve No. 1"); }

DEFINE_CG_MOTION(valve2, dt, vel, omega, time, dtime) { if (!Data_Valid_P()) {

Message("Pas bon du tout!\n");

return; }

NV_S(vel, =, 0.0); NV_S(omega, =, 0.0);

/*movement of the body*/ vel[1]=...; omega[2]=...;

Message("\n moving valve No. 2"); }

Than you can choose in the panel Dynamic Mesh Zones for the one valve the function called valve1, and for the another function valve2. I hope it's usefull. J
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Old   November 24, 2010, 09:15
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DuyThao
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Hi everybody......, I am a new in Fluent. I am solving the moving wall (Like wave generation in a Tank), but the wall moves with various discrete accelerations (not periodic function). I can't use DEFINE_CG_MOTION to simulate the moving wall .

Hope people can answer my questions....!!Thank so much.
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Old   November 24, 2010, 14:38
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Quote:
Originally Posted by ndthao View Post
... but the wall moves with various discrete accelerations (not periodic function). I can't use DEFINE_CG_MOTION to simulate the moving wall .

Hope people can answer my questions....!!Thank so much.
hi what is about fourier tratransformation. after the transformation you can transform the acceleration to the movement of your wall.
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Old   November 24, 2010, 21:59
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Quote:
Originally Posted by JohannVV View Post
hi what is about fourier tratransformation. after the transformation you can transform the acceleration to the movement of your wall.
My wall is assigned a motion with artificial earthquake (1500 values of discrete accelerations). I had transfered accelerations to velocity by using integrating discrete function.

My problem is that I can't define the motion of the wall with various discrete velocity (discrete acceleration) in DEFINE_CG_MOTION of Fluent. Because the velocity of wall are discrete values (not periodic function).

Hope people answer my questions...???? Thank a lot...!!!
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