TAGGED: ansysfluent, dpmmodel, dpmudfs, udfcompilation


June 27, 2022 at 3:02 pmkamatsaSubscriber
Hello. I am trying to introduce a force in the DPM_BODY_FORCE macro in the DPM model. The force is dependent on the flow velocity so I want to incorporate the flow velocity into the equation. My code is:
DEFINE_DPM_BODY_FORCE(DEP,tp,i)
{
double beta=L/D;
double xi=beta/sqrt((beta*beta1));
double c1=0.5*log((xi+1)/(xi1));
double f=xi*((1xi*xi)*c1*xi+xi);
double Fd=0;
if (TP_POS(tp)[0] >= 0.05)
{
if(i == 1)
{
Fd = 1* (pi * km * epsilon * D * D * L / 6) / (alpha / (alpha  1)  f) * pow(V / log(R2 / R1), 2) * pow(1 / TP_POS(tp)[1], 3)+pi*mu*D*4* fabs(TP_VEL(tp)[1])*(pow(beta,2)1)/((2*pow(beta,2)1)*(log(beta+sqrt(pow(beta,2)1))/sqrt(pow(beta,2)1)beta));
}
else if (i == 0)
{
Fd = 1*pi * mu * D * fabs(C_U(c,t)TP_VEL(tp)[0]) * 8 * (pow(beta, 2)  1) / ((2 * pow(beta, 2)  3) * (log(beta + sqrt(pow(beta, 2)  1)) / sqrt(pow(beta, 2)  1) + beta));
}
}
return(Fd/TP_MASS(tp));
}
I am getting the following error during compilation:
error: use of undeclared identifier 'c'
error: use of undeclared identifier 't'
Is this because I am using the flow variables in a different macro that does not have the variables t & c in its declaration. If yes, how do I fix this.
Some help would be appreciated. 
June 28, 2022 at 10:44 amRobAnsys Employee
Have a look at the example here https://ansyshelp.ansys.com/account/Secured?returnurl=/Views/Secured/corp/v221/en/flu_udf/flu_udf_sec_define_dpm_body_force.html

June 28, 2022 at 11:50 amDrAmineAnsys Employee
Check the manual for more examples.

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