ISSN:
1573-2959
Schlagwort(e):
Numerical simulation
;
Roughness sub-layer
;
Urban ground
;
Roughness parameters
;
Roof shape
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Energietechnik
Notizen:
Abstract Most of the mesoscale models use roughness parameters to characterise the ground and to compute the surface stress. As the experimental determinations of the urban roughness parameters are rare and not very reliable, a new methodology based on microscale numerical simulations is presented here and the first results from two-dimensional simulations with different roof shapes are analysed. Firstly, it appears that the roof shape has a large influence : large difference in the Reynolds stress profile and in the roughness sub-layer thickness, enhancement of the exchanges at the roof level by buildings with attic. It also appears that the fetch necessary to obtain a constant flux layer is unrealistic compared to the real spatial homogeneity of quarters in European cities. Consequently, a new parameterisation of the urban ground-induced friction is to be developed without reference to the constant flux layer theory.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1023/A:1006448007014
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