[L.Gordo]

Hello everyone,

I'm trying to simulate an air flow through the geometry you can see in attachment. The input face is the square one, that is in red colour, and it has two output faces, you can see one of them in green, the other one is quite similar, although the problem is not symmetrical.

In the output faces, i set output pressure, and for the input i have an UDF, both for velocity and for temperature (you can see them at the end of the mail).

At first, i've simulated without the energy equation, just velocity and once it converge y add the energy equation to the problem and set the temperature input with the UDF. But at that moment residuals become unestable (you have a picture of them attached), i've tried to reduce the URF for energy equation, but the problem remain.

Any suggestion about how can i solve this?


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UDFs:
#include "udf.h"

DEFINE_PROFILE(inlet_y_velocity, thread, position)

/* Definición costantes de la ecuación que define nuestra superficie */

#define H 1.42 /*surface high*/
#define V 0.46209 /*average speed*/
{
real x[ND_ND]; /* this will hold the position vector */
face_t f;

begin_f_loop(f,thread)
{
F_CENTROID(x, f, thread);
F_PROFILE(f, thread, position) = 2 * V * x[2]/H;

}
end_f_loop(f, thread)
}

DEFINE_PROFILE(inlet_temperature, thread, position)

/* Definición costantes de la ecuación que define nuestra superficie */

#define H 1.42 /*surface high*/
#define T 75 /*Variation of temperature*/
{
real x[ND_ND]; /* this will hold the position vector */
face_t f;

begin_f_loop(f,thread)
{
F_CENTROID(x, f, thread);
F_PROFILE(f, thread, position) = 25 + (T * (H-x[2])/H);

}
end_f_loop(f, thread)
}

---------------------------------------------------------------------

[blackmask]

I suggest that you should convert the temperature from Celsius to Kelvin.

[L.Gordo]

Originally Posted by blackmask

I suggest that you should convert the temperature from Celsius to Kelvin.

Thanks blackmask!

I feel quite fool with this mistake... BTW i fixed it and it is calculating, hope it works now