[rocketeer]

I am writing a UDF to define an unsteady velocity profile at an inlet of a domain. I will show a sample of the code and explain what am I looking for.

#include "udf.h"

DEFINE_PROFILE(unsteady_velocity, t, i)
{
face_t f;
real t = CURRENT_TIME;
real velocity = V_e
real pressure = P_stat

Domain *domain;
Thread *c_thread;
thread_loop_overset_c(c_thread, domain) /*loops over all cell threads participating in overset */
/*interfaces in the domain */
{

V_e = SQRT(Ux^2 + Uy^2 + Uz^2)
P_stat
}

begin_f_loop(f, thread)/*begin calculation*/
{
F_PROFILE(f, thread, position) = (cst*V_e + cst*(P_stat + 3500*t) - x_wall_shear_stress(cylindrical_wall) - static_pressure(cylindrical_wall) - (cst- cst*t)*cst);
}
end_f_loop(f, thread)
}

I want to calculate the velocity at the inlet as seen by the f_loop;
cst is a constant number, V_e is the velocity at a fluid interface, P_stat is the static gauge pressure at that interface too inside my global domain, moreover calculating the x-wall shear stress on a cylindrical wall inside the global domain with the static pressure at this cylindrical wall also. t is the real-time or time step of the transient simulation. I am using the pressure-based coupled algorithm.
My request is: how to properly code this velocity equation?

[Oula]

Originally Posted by rocketeer

I am writing a UDF to define an unsteady velocity profile at an inlet of a domain. I will show a sample of the code and explain what am I looking for.

#include "udf.h"

DEFINE_PROFILE(unsteady_velocity, t, i)
{
face_t f;
real t = CURRENT_TIME;
real velocity = V_e
real pressure = P_stat

Domain *domain;
Thread *c_thread;
thread_loop_overset_c(c_thread, domain) /*loops over all cell threads participating in overset */
/*interfaces in the domain */
{

V_e = SQRT(Ux^2 + Uy^2 + Uz^2)
P_stat
}

begin_f_loop(f, thread)/*begin calculation*/
{
F_PROFILE(f, thread, position) = (cst*V_e + cst*(P_stat + 3500*t) - x_wall_shear_stress(cylindrical_wall) - static_pressure(cylindrical_wall) - (cst- cst*t)*cst);
}
end_f_loop(f, thread)
}

I want to calculate the velocity at the inlet as seen by the f_loop;
cst is a constant number, V_e is the velocity at a fluid interface, P_stat is the static gauge pressure at that interface too inside my global domain, moreover calculating the x-wall shear stress on a cylindrical wall inside the global domain with the static pressure at this cylindrical wall also. t is the real-time or time step of the transient simulation. I am using the pressure-based coupled algorithm.
My request is: how to properly code this velocity equation?

I believe you need to define U, also if cst is constant then why don't you put it in the equation to avoid any confusion. One last comment, can you write your equations without coding.