[Sdezmond]

Hello

I'm trying to send a wave down a tank/conduit that is 100m long and 5x5m and filled with 1m of water. To do this im using a UDF to vary the flow at the input face of the tank (one end). essentially all the UDF is supposed to do is check the time, as an if statement to the effect of; if the time is greater than A, but less than B, then set input mass kg/s to x, else set input mass kg/s to y.

This is my first attempt at using fluent or indeed any CFD and im having problems getting it working. I've written two UDFs; one that just inputs a constant flow. I figured if i could get it working at least i would know the basic syntax etc. And one that inputs a wave/flow rise and decline. The first UDF does load in to fluent but doesnt produce the desired result (i don't get any water flowing down the tank), the second wont load as there are syntax issues with the If statement (im not a very experienced programmer and no little about c).

heres my code, can any one give me some pointers?

============
UDF 1 a constant flow

#include “udf.h”

DEFINE_PROFILE(constant_in, t, nv)
{
real x[ND_ND]; real v; face_t f;


begin_f_loop(f,t)
{

F_CENTROID(x,f,t);
v=2;
F_PROFILE(f,t,nv) =v;
}
end_f_loop(f,t)




#include “udf.h”

DEFINE_PROFILE(wave_in, t, nv)
{
real x[ND_ND]; real v =5; face_t f;
real T;
real a =2;
real b=4;


begin_f_loop(f,t)
{

F_CENTROID(x,f,t);
T=RP_Get_real(“flow-time”);

if (T>=a, T<=b);
{

F_PROFILE(f,t,nv) =v;
}
else
{
F_PROFILE(f,t,nv) =2;
}
}
end_f_loop(f,t)
}