[zakir]

Hi there,

For my 3rd year project I have to simulate trailing vortices upstream of a 3D wing with a flap. These trailing vortices are from another airplane that has just taken off. The whole idea is to capture the effect of these wake vortices on this wing in take-off configuration. Does anyone know how I could go about setting up these vortices in fluent? I have been told that I can set them as an initial condition in fluent and that I would need to input a user defined function for them. Would this UDF consist of the velocity field of the vortices? Any help with this would be much appreciated .

Zakir

[zakir]

Given that the above comment was quite vague, I will give more clarity here. I am trying to set an initial condition for a point vortex upstream of my wing. The code I have used is shown below. I have no idea whether this is correct or not so if someone could give any help it would be much appreciated:

/************************************************** *********************
vprofile.c
UDF for specifying point vortex
************************************************** **********************/

#include "udf.h"

#define gamma -779.17 /*define vortex strength*/
#define r 0.5 /*define cross-sectional size of vortex*/
#define uinf 78.23 /*define free-stream velocity*/
#define alpha 15 /*define angle of attack*/
#define pi 3.14159265358979323846 /*The number pi*/

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

begin_f_loop(f, thread)
{
F_CENTROID(x,f,thread);
y = x[1];
F_PROFILE(f, thread, position) = uinf;
}
end_f_loop(f, thread)
}

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

begin_f_loop(f, thread)
{
F_CENTROID(x,f,thread);
y = x[1];
F_PROFILE(f, thread, position) = -gamma/(0.71*pi*(r/0.5));
}
end_f_loop(f, thread)

}

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

begin_f_loop(f, thread)
{
F_CENTROID(x,f,thread);
y = x[1];
F_PROFILE(f, thread, position) = -gamma/(2*pi*(r/0.5));
}
end_f_loop(f, thread)
}