[Joao Bomfim]

Dear all,
I'm trying to do a simulation in parallel with deploying a simple UDF, to increase the rotation speed (RPM) smoothly. UDF build and load normally. The UDF is bellow:

#include "udf.h"
DEFINE_ZONE_MOTION(fmotion, omega, axis, origin, velocity, time, dtime)
{
    #if! RP_HOST
    if (time < 0.15)
    {
        *omega = 2400.0 * time;
    }
    else
    {
        *omega = 400.0;
    }
    N3V_D(velocity, =, 0.0, 0.0, 0.0);
    N3V_S(origin, =, 0.0);        /* default values, line could be omitted */
    N3V_D(axis, =, 0.0, 0.0, 1.0);     /* default values, line could be omitted */
    #endif
    return;
}

When I run the fluent with the UDF, I get the error "Error at host: floating point exception". The case runs in double precision and 4 partitions.
Does anyone have any idea how to fix it?
All te best for all.

[Joao Bomfim]

To include: Fluent runs by Visual Studio prompt.

[Joao Bomfim]

Update: Fluent with UDF runs normally in serial mode, but without directive #if !RP_HOST. Someone have an idea?

[AlexanderZ]

you don't special macros for parallel for this code
you don't need:

 #if! RP_HOST

Ansys FLuent Customization manual, Parallelizing Your Serial UDF chapter

best regards

[Joao Bomfim]

I DONT BELIEVE!!!
I swear I Tried this, but I think tried without VS prompt inicialization.AlexanderZ, I'm very very grateful, I dont know how I let this escape. Thanks so much again, have a great Day!!!!

[Joao Bomfim]

Taking advantage of the post, how could I monitor the angular velocity? Did he have to get tangential velocity and divide by radius? (Simulation of a VAWT with sliding mesh). Or is there an easier way? If I have to use the tangential velocity, which Report Type is most appropriate? Thanks in advance.

[AlexanderZ]

I have no experience about it, there are several tutorials on youtube
https://www.google.com/search?q=Simu...hrome&ie=UTF-8

best regards

[Joao Bomfim]

I think I got.

• Report definitions -> Surface report -> Integral and field variable = Tangential velocity for one blade of vawt.
• Report definitions -> Surface report ->Area for the same blade of vawt.
• Create an expression like this: (Tangential Velocity of blade/Area of blade)/Radius of vawt. The result will be angular velocity of turbine, if the CAD geometry is ok. In my UDF, angular velocity is increased up to 400 RPM in 90 timesteps. Looks like this worked. Big hug!