Reports wind tunnel tests of wind velocity, RMS velocity fluctuations and energy spectra for the streamwise velocity component in the lee of model fences of permeability 0% 20%, 34% and 50%. Compares results with existing field and wind-tunnel data. Turbulence measurements define the leeward flow regions which are dominated respectively by the bleed flow and by thedisplacement flow. Gives separate empirical relationships between mean velocity and turbulence intensity for these two regions.
Describes apparatus and experimental techniques for full and model scale measurements on test buildings. Discusses "blocking effect" of a large model in a small tunnel. Shows that model law derived in part one is valid forphenomena dependent on wind velocity. Compares model to full-scale tests. Discusses air flow around a house, pressure on walls and different types of roofs
Describes instrumentation used to measure air flow and pressure. Presents laws for turbulent and laminar flow in a wind tunnel. Reports model experiments to investigate the flow behind a solid screen and control experiments to check the model laws. Discusses measurements made at full scale on a school and on a model of the school. Describes experiments on the shelter behind houses and the dispersal of smoke from a chimney.
Reports comparisons between wind pressures measured on two low-rise experimental buildings and pressures measured on wind-tunnel models of those buildings. For the experimental building at Aylesbury, comparisons are made between thefull-scale pressures obtained by the Building Research Establishment and those of model tests at 1: 500 scale carried out by the University of Western Ontario, Canada and at 1 :50 scale by Virginia Polytechnic Institute and State University (V.P.l.S.U.). The second experimental building, constructed by V.P.l.S. U.
Reports measurements of wind pressure distributions on a model of tall building made in a turbulent wind tunnel with a velocity gradient. The wind pressure distributions in a constant uniform velocity field were also measured and the differences in thepatterns of pressure distributions due to the effects of velocity gradient were observed at lower part of the model.< Also describes measurement of natural wind pressures and glass strains on a 36 storey office building. Finds inter alia considerably large pressure fluctuations of short gusts although average pressures are small.
Discusses the physical nature of atmospheric boundary layer flows. Concludes that the primary aims in the simulation of these flows in a wind tunnel should b to model the relevant scales and intensities of turbulence. Simulation of the variation of mean wind velocity with height is also desirable. Proposes a system of barriers and vortex generators as a means of simulating turbulent and neutral atmospheric boundary layers.Discusses the characteristics of induced turbulent flow. Finds that the developed flow is a good approximation to the natural boundary layer.
Reports wind-tunnel measurements of wind pressure on a rectangular block. Presents results as mean isobars plotted on an exploded view of the surfaces of the model. Briefly discusses the effect of turbulence and fluctuating pressures. Concludes that mean pressure distribution is only slightly affected by turbulence and shear in the atmospheric wind.
Reports an investigation of wind loading with emphasis on the local pressure fluctuations, on a small scale building model in a thick turbulent boundary layer wind tunnel. A striking similarity between the oncoming turbulent energy spectra andsurface pressure-fluctuation spectra was consistently observed. This similar behaviour suggests that the upstream turbulence plays a dominant role in producing the pressure fluctuations on the upwind face of a bluff body.
Reports experiments carried out in a wind tunnel on two kinds of two-dimensional roughness arrays and on one array of three-dimensional roughness with a turbulent boundary layer growing over the arrays. Drag coefficient on an individual element was measured by pressure tapping as its height was varied relative to the average height of the array. Some general forms for the drag coefficients are found for the two-dimensional case. Results for the three dimensional case show some general trends but more work is needed.
Discusses the effect of wind on air change rates in buildings. Reports series of model tests conducted in a water flume and a wind tunnel. A plexiglass box with holes in it was filled with gas, either nitrogen or carbon dioxide, and placed in a controlled air flow. The concentration of gas was plotted in a semi-logarithmic form. Gives typical examples of these graphs.Discusses feasibilty of estimating rate of air change by a hyperbolic function, but finds that more tests are needed forpractical recommendations.
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