Wind tunnel simulation of atmospheric boundary layer flows

Abstract

The present work shows how thick boundary layers can be produced in a short wind tunnel with a view to simulate atmospheric flows. Several types of thickening devices are analysed. The experimental assessment of the devices was conducted by considering integral properties of the flow and the spectra: skin-friction, mean velocity profiles in inner and outer co-ordinates and longitudinal turbulence. Designs based on screens, elliptic wedge generators, and cylindrical rod generators are analysed. The paper describes in detail the experimental arrangement, including the features of the wind tunnel and of the instrumentation. The results are compared with experimental data published by other authors and with naturally developed flows

Wind tunnel simulation of the atmospheric boundary layer for studying the wind pattern at Centro de Lançamento de Alcântara

“…It varies from 0.11 for smooth surface as lakes and the ocean to 0.34 for cities with high density of buildings. For the ocean surface, some studies consider between 0.11 (Hsu et al, 1994;Barbosa et al, 2002) and 0.15 (Blessmann, 1973).…”

“…The simulation of an ABL in a wind tunnel with short-test section is quite complicated and there are several methods for this purpose discussed in the literature (Counihan, 1969). A simple way of generating thick boundary layers is by using passive methods (Barbosa et al, 2002;Loredo-Souza et al a combination of spires, wedges or grids together with roughness elements distributed on the wall. Ten possible ways of simulating neutral, stable, and unstable atmospheric conditions in different wind tunnel types were described in Hunt and Fernholz (1975).…”

“…Ten possible ways of simulating neutral, stable, and unstable atmospheric conditions in different wind tunnel types were described in Hunt and Fernholz (1975). A short review of the techniques used to thicken the boundary layer was presented by Barbosa et al (2002). Besides, thickening devices with sophisticated geometry were described by Ligrani et al (1979 and1983).…”

CFD validation of ABL in short wind tunnel chamber along an empty domain

“…Therefore advanced and original techniques for generation of the main characteristics of natural winds, as well as the formation of the atmospheric boundary layer (ABL) in short test-section boundary-layer wind tunnels (SBLWT) are required. These techniques will allow to use shorter test sections of wind tunnels for simulating the characteristics and behaviour of the atmospheric boundary layer (Barbosa, et al, 2000;Shojaee, et al, 2014). The computational fluid dynamic (CFD) simulation of the ABL has become an important research subject.…”

Development and Validation of an in-House CFD Code for Environmental Flow Simulation Using Measurements in Atmospheric Boundary Layer Wind Tunnel

“…The majority of pollutants emitted from sources of air pollution in urban areas are released into the part of the atmosphere adjacent to the earth's surface. This part is known as the atmospheric boundary layer which has a typical height of 500-600 m [1,2]. The environmental flow is usually characterized by a turbulent weakly compressible flow occurring in the atmospheric boundary layer.…”