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Nigel Banks March 9, 2005 13:23

3D UDF - Profile dependant on ground height
Hi there,

I am modelling the flow around a group of buildings situated on undulating ground. My initial model used a flat ground and I sucessfully used the UDF below to model the atmospheric boundary layer velocity inlet conditions (velocity increases with distance above ground).

However, I have now included the local hills and so have different ground levels along the inlet. Is there any way to reference the coordinates of lower edge (which would give me the ground height at that point) in order to get the correct velocity profile???

Any help is very appreciated!!!

Many thanks, Nigel

#include "udf.h"

DEFINE_PROFILE(ABL_profile, thread, index)


real x[ND_ND];

real y;

face_t f;

begin_f_loop(f, thread)



y = x[1];

F_PROFILE(f, thread, index) = 1.465*log((y+0.01)/0.01);


end_f_loop(f, thread)


SteveGoat September 5, 2012 06:50

Dear Nigel,
have you solved this issue?
I'm facing the same problem and it would be very useful to know your opinion about it

Many thanks

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