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-   -   Developing velocity profile in virtual wind tunnel (http://www.cfd-online.com/Forums/cfx/25015-developing-velocity-profile-virtual-wind-tunnel.html)

Nicki Parker January 10, 2008 12:30

Developing velocity profile in virtual wind tunnel
 
I am simulating the wind microclimate around a new development using a (virtual) cylindrical wind tunnel. At the inlet (around 800m upstream of the site) I am specifying a reference velocity of 14m/s at 10m above ground level with an SST turbulence model. The problem I have is that the flow is developing as it travels through the domain, and by the time the air gets to the site, it has increased in speed (at 1.75m above ground, it is around 14m/s, rather than the desired 7.7m/s (from the log law)). The velocity at the reference level of 10m has also increased, but not by as much (instead of being at 14m/s it is at 16m/s). Can anyone advise a solution or work around to this problem, as the wind speeds around the site are surely over-estimated.

Thanks in advance,

Nicki

eslam January 10, 2008 15:10

Re: Developing velocity profile in virtual wind tu
 
you must used from log low in expersion for wind velocity: u/u*=(1/k)ln(z/z0)

Nicki Parker January 11, 2008 06:02

Re: Developing velocity profile in virtual wind tu
 
I've done that.


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