Learning Forum

[navarag kk]

i am trying to simulate a door opening due to fluid pressure. The inlet condition is velocity inlet of 10m/s. the udf code is compiling. the MI is constant. but I am not getting the door opening motion even after hooking the udf code and Define_adjust code.

 

the code is

#include "udf.h"

#include

static real omega_calc = 0.0;

static real theta=1.082104136;/*need to check*/

/*extern real omega_out=0.0; */

real torque_p;

DEFINE_ADJUST(torque_calculation,domain)

{

/* Variables used by serial, host, node versions */

int surface_thread_id=9;/*door surface id from fluent*/

real total_area=0.0;

torque_p=0.0;

Thread* thread;

face_t face;

real area[ND_ND];

real NV_VEC(A);

real w[ND_ND];

thread = Lookup_Thread(domain,surface_thread_id);

begin_f_loop(face,thread)

/* If this is the node to which face "officially" belongs,*/

/* get the area vector and pressure and increment */

/* the total area and total force values for this node */

{

F_AREA(area,face,thread);

total_area += NV_MAG(area);

F_AREA(A,face,thread);

F_CENTROID(w,face,thread);

torque_p += F_P(face,thread)*NVD_DOT(A,w[1],w[0],0);/*need to check -w[1],w[0] as per geometry*/

}

end_f_loop(face,thread)

}

DEFINE_CG_MOTION(move_flapper,dt,vel,omega,time,dtime)

{

NV_S(omega, =, 0.0);

node_to_host_real_1(torque_p);

real torque, domega, omega_prev, omega_dot, omega_out;

const real inertia = 3.2;

/* Compute the torque due to pressure P and weight W */

/*-----------------------------------------------------------------------*/

/*torque_w= -9.1469 * sin(theta); /* -g*L*W*sin(theta) */

torque= torque_p ;

domega = dtime * torque / inertia;

omega_dot= torque / inertia;

/* Calculate the angular velocity */

/*-----------------------------------------------------------------------*/

omega_prev = omega_calc;

omega_calc = omega_calc + domega;

omega_out = omega_calc;

/* Calculate the angle theta (Taylor expansion) */

/*-----------------------------------------------------------------------*/

theta=theta + 0.5*dtime*(omega_prev+omega_calc);

#if !RP_NODE

Message ("\ntorque_p = %f,", torque_p);

Message ("\ntorque = %f,", torque);

Message ("\ndomega = %f,", domega);

Message ("\nomega_calc: %f\n", omega_calc);

Message ("\n---------------------------------------");

Message ("\ntheta: %f\n", theta);

#endif

}

[SRP]

Hi,

I suggest you to please check forum discussion on opening and closing of valve which is done using udf: https://forum.ansys.com/forums/topic/how-to-do-a-udf-to-simulate-the-opening-and-closing-of-compressor-valves/

Hope you will find this useful.

Thank you.

[navarag kk]

I am new to udf and that forum uses other macros which i havent used. Should i change my entire code or can i work on this code?