[kywong5]

Hi all,
I would like to prescribe a uniform velocity of 100m/s at an inlet by using the time argument. But I'm afraid that the way i write the code does not represents what I mean.
When I run the code, the velocity at the inlet is less than 100 m/s (around 20-30m/s). But there is no issue with the timing.

************************************************** *******
if ((the_current_time>=0) && (the_current_time<2))
{
velocity=100.00;
}
************************************************** *******

[pakk]

You should give your complete code if you want help...

You are using a DEFINE_PROFILE, I guess? Give the complete code for this DEFINE_PROFILE.

[kywong5]

DEFINE_PROFILE(velocity_magnitude, t, i)
{
real velocity;
real the_current_time;
face_t f;

the_current_time = CURRENT_TIME;

if ((the_current_time>=0) && (the_current_time<2))
{
velocity=100.00;
}
else if ((the_current_time >=2))
{
velocity=0.00;
}

begin_f_loop(f,t)
{
F_PROFILE(f,t,i) = velocity;
}
end_f_loop(f,t)
}

Thank you

[pakk]

It looks to me that you have written a clear code that should do what you said, I can not see any mistake.

I don't understand why it does not work for you. If you don't use a UDF, but fix the velocity in Fluent (so ignoring the time), does it work then?

[kywong5]

It works without the UDF.
Red region represents 100m/s.
<https://ibb.co/iHAbDk>

By the way, I have another question.
How can I increase the red region as shown in below image (from literature)? The literature also using the same velocity 100m/s.
<https://ibb.co/foWcKQ>