Continuum or neighbourhood scale

Above z = z , but within the internal layer, the mean velocity profile is found in many experiments to have the form of equation (2.1). Despite the unevenness and inhomogeneity of these boundary layer flows, the ratios of the r.m.s. values of the three components of turbulent velocity to the friction velocity n, are quite comparable with their values over level terrain, i.e. cru/ut - 2.5, crv/ut - 1.3, Rotach, 1995 [547], 

In this review we particularly consider how detailed flow modelling in and around individual buildings and the surrounding streets is useful for understanding dispersion. Also, detailed studies of these local scale flows are necessary, as explained in the previous section, to develop models over neighbourhood scales for flow and dispersion. 

Fully computational methods (FCM), using a variety of turbulence modelling methods, have been extensively applied to computing flows around single buildings in turbulent boundary layers. Using turbulence closure methods many models have predicted mean 

For tall structures (where H/b 1) in turbulent boundary layers the recirculating flow field in the wake is a region where streamlines enter and leave from the external flow (Lawson et al., 1988 [361]). Although in general there is no closed streamline bubble , because of the high turbulence there is strong mixing in the horizontal 

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