engleski

Wind Flow Simulation under Thermally-Stratified Atmospheric Boundary Layer

Detailed characteristics of thermal effects in wind-tunnel simulations of the Atmospheric Boundary Layer (ABL) flow developing above hill terrain are discussed in the paper. There are two main reasons for simulating ABL in a wind tunnel. One reason is to help the understanding of airflows in the atmosphere. The other is to help solve engineering and environmental problems, such as, predicting the wind forces on structures, predicting the way in which the structures affect the wind, and studying diffusion from various sources of air pollution. The principle designs are focused on features such as dealing with strongly stratified, low turbulent flows and it is also focused to have enough dimensions of the test section for topographic model experiments. This paper presents convective boundary layer of the ABL flow develops as the ground is warmed up by the solar radiation and the thermally induced turbulence. Particle Image Velocimetry (PIV)experiments were carried out in order to distinct contributions of thermally- and mechanically induced atmospheric turbulence for a number of characteristic topographies and urban areas. Stratification effects between the windward and leeward hillsides were investigated for different upwind velocity and ABL flows. Buoyancy effects on turbulent boundary layers in a wide range of stability conditions defined using the Richardson number (Ri) were focused. Convective Boundary Layer (CBL) of the ABL flow develops as the ground is warmed up by the solar radiation and the thermally induced turbulence were simulated. These effects were modelled in the Vincenc Strouhal Climatic Wind Tunnel in Telč creating the “heat” islands in the scaled model.

Atmospheric boundary layer ; Thermal stratification ; Laboratory experiments

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