[Kenzhia3310]

I have an issue about parabolic velocity profile in my .c file.
I want to create a parabolic inlet with 0.3m/s max speed and pipe diameter is 8mm.
And I found this code from the others, is this applicable for my case?

THE CODE SHOWN AS BELOW:
#include "udf.h"

DEFINE_PROFILE(inlet_x_velocity, thread, position)
{
real x[ND_ND]; /* this will hold the position vector */
real y, h;
face_t f;

h = 0.004; /* inlet height in m */

begin_f_loop(f,thread)
{
F_CENTROID(x, f, thread);
y = 2.*(x[1]-0.5*h)/h; /* non-dimensional y coordinate */
F_PROFILE(f, thread, position) = 0.3*(1.0-y*y);
}
end_f_loop(f, thread)
}

[vinerm]

Yes, this would work.

[Kenzhia3310]

I have applied the parabolic velocity into my biogas-air premixed combustion.
However, I didn't get my expected result.
Here is my settings for the system(Stoichiometric mixtures)
1.Air fuel inlet velocity: 0.3 m/s parabolic velocity
Coflow inlet velocity: 0.05m/s
2. 40% CO2 and 60% CH4 for fuel; 21% O2 and 79% N2 for air
3. Mole fraction (air fuel inlet): CH4= 0.0894, O2 = 0.1788, N2 = 0.6722, CO2 = 0.0596

Is there any problem for my settings here to get the flame?

[vinerm]

Parabolic velocity profile has got nothing to do with flame. Even if you use flat profile, it may or may not result in flame. Combustion depends on correct setup of combustion model, initialization, material properties, and thermal boundary conditions.