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

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

I've done that.