Mean Wind Profiles and Change of Terrain Roughness

Soft open points based load restoration for the urban integrated energy system under extreme weather events

“…where d f (t) is the distance between the studied location and the typhoon centre at time t. The value of parameter n is usually 0.5~0.7 [32] and is taken as 0.6 in this paper [30].…”

“…The wind speed V R,f ( t ) at a certain location in the typhoon wind field can be expressed as $$${V}_{R,f}(t)=\left\{\begin{array}{c}\begin{array}{ll}{V}_{R\mathrm{max}}(t)/{R}_{\mathrm{max}}(t),\hfill & {d}_{f}(t)\le {R}_{\mathrm{max}}\hfill \end{array}\\ \begin{array}{ll}{V}_{R\mathrm{max}}(t){\left({R}_{\mathrm{max}}(t)/{d}_{f}(t)\right)}^{n},\hfill & {d}_{f}(t) > {R}_{\mathrm{max}}\hfill \end{array}\end{array}\right.,f\in \left\{1,2,{{\cdots}},h\right\}$$$ where d f ( t ) is the distance between the studied location and the typhoon centre at time t . The value of parameter n is usually 0.5~0.7 [32] and is taken as 0.6 in this paper [30].…”

Wind Loading of Structures: Framework, Phenomena, Tools and Codification

“…The mean profile coefficient c m depends on three main quantities: the roughness of the terrain, the topography, and the atmospheric thermal stratification. Codes and most engineering applications assume that the terrain that surrounds the structure has homogeneous roughness and express the profile of the mean wind velocity, as a function of the height z above ground, by means of a power law [35] or a logarithmic law [36,37], whose application is restricted to the atmospheric inner boundary layer, up to about 200 m above the ground level, where the mean wind velocity vector does not exhibit any rotation due to the Ekman spiral; of course the mean wind velocity decreases on increasing the terrain roughness. Topography effects are usually considered by multiplying the mean wind velocity profile by a topography coefficient c t whose definition is limited to simple orographic reliefs such as hills, ridges and escarpments [38][39][40][41].…”