[akshay777]

Hi there,
I've been working on Ansys Fluent for 4 months, I want to add ejector forces using UDF. I have successfully compiled the UDF including mass and moment of inertia, Now I want to add ejector forces using "if else" statement....but I'm unable to add the same....and I dont have much knowledge about C program.....please help...

[annan]

Dear Akshay,
We would probably be able to help you if you post your UDF, and describe in detail what are the conditions you want to use for your "if" statement.
Regards,
Annan

[akshay777]

I'm doing a project on store separation from wing of airplane ✈....I have added the mass and MOI of body but it gave me "Negative cell volume error" Everytime....here is the code I have used -

#include "udf.h"

DEFINE_SDOF_PROPERTIES(delta_missile, prop, dt, time, dtime)
{
prop[SDOF_MASS] = 627.233;
prop[SDOF_IXX] = 324.7894;
prop[SDOF_IYY] = 8.4564;
prop[SDOF_IZZ] = 324.7894;

/* add injector forces, moments */
{
register real dfront = fabs (DT_CG (dt)[2] -
(0.179832*DT_THETA (dt)[1]));
register real dback = fabs (DT_CG (dt)[2] +
(0.329184*DT_THETA (dt)[1]));

if (dfront <= 0.100584)
{
prop[SDOF_LOAD_F_Z] = 10676.0;
prop[SDOF_LOAD_M_Y] = -1920.0;
}

if (dback <= 0.100584)
{
prop[SDOF_LOAD_F_Z] += 42703.0;
prop[SDOF_LOAD_M_Y] += 14057.0;
}
}

printf ("\ndelta_missile: updated 6DOF properties");
}



In this, I have not understood the adding ejector forces to the body.....one more....I'm I really need to define cell ID and thread pointer for adding the ejector forces....??thank you