CFD Online Discussion Forums

CFD Online Discussion Forums (
-   CD-adapco (
-   -   Atmospheric Wind Profile - Inlet Subroutine (

Roger December 11, 2002 21:38

Atmospheric Wind Profile - Inlet Subroutine
Hi looking for some help on the above topic.

Has anyone created a user subroutine to model the variation of velocity for an inlet based on the ashrae standard for a typical atmospheric wind profile, typically of the form:

Uh=Umet(Omet/Hmet)^Amet * (H/O)^A where

A = Exponent in power law wind speed profile for local building terrain

Amet = Exponent for the meteorological station

H = Height from ground level (m) Hmet = Height at which meteorological wind speed was measured (normally at 10 m above ground) (m)

Uh = Approach wind speed at upwind wall height (m/s)

Umet = Hourly meteorological wind speed, measured at height (m/s)

O = Fully developed strong wind atmospheric boundary layer thickness (m)

Omet = Atmospheric boundary thickness at the meteorological station (m)

i.e. wind speed for the inlet varies with height up to a maximum of 10m.

Any help appreciated



raymond December 12, 2002 06:43

Re: Atmospheric Wind Profile - Inlet Subroutine
I have done much simulation about environment study, with the user subroutine inlet boundary condition. The equation is just the same as you described. It's the function of elevation and quite easy to be applied in the subroutine. I don't know what's the problem of you? The parameters or others?

Roger December 12, 2002 06:49

Re: Atmospheric Wind Profile - Inlet Subroutine
Not sure how to apply a subroutine in StarCD - unfortunately not very good with fortran code. I believe I have to make one up, or is there a subroutine to pick in the software itself??



CJ Tune December 12, 2002 11:00

Re: Atmospheric Wind Profile - Inlet Subroutine
Try using the BCDEFI.F subroutine. To use it, set your inlet b/c options=user and click on 'define coding'. There will be a new folder called 'ufile' in your working directory with the file BCDEFI.F in it. Open with your favourite text/Fortran editor. Follow the example script and make use of the X,Y, and/or Z variables to program your inlet velocity as a function of boundary position. Take a peek in the file that is also there.

All times are GMT -4. The time now is 14:26.