[itsme_kit]

I wanna put a log wind speed profile at inlet for ABL flow modelling

It's a 3D case

I wonder which thread I should use. cell thread or face thread

Thanks in advance

[amir2920]

In my opinion face thread,

[A CFD free user]

When you talk about profile, you must define your UDF in thread except the case you want to fix values in a specific zone. In this case, you can use C_PROFILE and flag on the cell zones.

[itsme_kit]

Originally Posted by amir2920

In my opinion face thread,

Thanks for your reply

A little bit further discussion

when I declare x in real, should x be ND_ND or (ND_ND)*(ND_ND) in my case

Normally x[1] is for y direction and x[2] is for z direction

In my case, the square inlet contains lots of faces in either y or z direction

[itsme_kit]

Originally Posted by A CFD free user

When you talk about profile, you must define your UDF in thread except the case you want to fix values in a specific zone. In this case, you can use C_PROFILE and flag on the cell zones.

Thanks for your reply at first

I only want a velocity profile at inlet, that's every enough for me to avoid complication

I dont quite get your point in c_profile and flag

Do you mind clarifying them in detail

Many thanks