Sets out the similarity requirements which must be observed so that results of wind tunnel tests may be used to predict behaviour of full-scale prototypes in the natural wind. Discusses rigid models, suspension bridges, models of slender towers. Outlines problems of representing natural wind and the effect of wind tunnel-wall interference. Introduces correction procedure for wake blockage which permits the use of larger wind-tunnel models than would otherwise be possible without serious errors.
Discusses use of long boundary layer wind tunnel to produce a more realistic model of natural wind than that obtained in conventional aeronautical wind tunnel. Reports tests made tofind wind velocity profile and model tests to find dynamic response to wind loads and local pressures on buildings. Finds aeroelastic model response in turbulent flow is markedly different from that in smooth uniform velocity. Concludes that adequate simulation of natural wind has been obtained. Finds comparison between model and full-scale tests is encouraging.
Reviews work done on the physical and biological effects of wind-breaks and shelter-belts, outlining main results. Discusses reduction in mean speed of wind, turbulence produced by shelter-belt, shading and humidity. Outlines some biological consequences of shelter-belts. Gives bibliography containing forty-seven references.
Reports measurements of air change rates made on approximately 250 dwellings, occupied by low income households in 14 cities, in all major climatic zones of the United States. Two types of measurements were used : a tracer-gas decay technique using air sample bags and a fan depressurization test that measures induced air exchange rates. Shows that for this group of dwellings natural air infiltration rates have an approximate lognormal distribution.
Discusses problem of assessing wind loads on buildings. Describes general properties of the wind and suggests wind can be described by its mean velocity with superimposed gusts. Suggests averaging period of 10-15 minutes for the mean velocity. Gives empirical expression for wind spectra. Considers relationship between extreme value of wind speed and the parent distribution. Suggests influence of gusts is not best determined by maximum gust speeds. Finds mean wind speed profile and turbulent structure are strongly dependent on terrain.
Describes experimental techniques used to produce turbulent boundary layers in a wind tunnel. Gives model law for velocity profile in a turbulent flow over a rough surface. Describes wind tunnel, five tunnel coatings used to generate turbulence, themodels and instrumentation. Gives as an example the test results from a model of house with desk roof.
Reviews some previous work on the measurement of wind pressures at full-scale. Deals with some of the problems arising. Describes pilot investigation being made at State House, Holborn to develop suitable techniques and to study the effect of gusts on pressure distribution. Gives preliminary results and mentions problem of establishing a suitable reference pressure.
Gives method for calculating air infiltration through window cracks. Calculates pressure drops across windows in buildings for four types of building and discusses resulting pressure differences. Gives values for crack width and length. Recommends design values for rates of air change due to infiltration in buildings heated by off-peak electricity.
Describes method of estimating roughness required to generate velocity profile of a given shape with a boundary layer of agiven depth. Uses data correlation for the wall stress associated with very rough boundaries and a semi-empirical calculation method to calculate the shape of boundary layers in exact equilibrium with the roughness beneath them. Results can be summarized in a single figure which relates shape factor of boundary layer to height of roughness elements and their spacing
Reports natural exposure test on vertical joints in open-jointed rain screen cladding. Describes test rig and gives results of water penetration tests. Gives design recommendations for screens.
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