wind

Describes different methods for sealing joints. Gives method for testing permeability of joints to wind and rain. Concludes that two-stage joint seems to offer the greatest advantages which are long life, lack of need for maintenance, lack of sensitivity to tolerances, extensive lack of sensitivity to faulty installation practice and installation independent of the weather. Tests confirm that the wind permeability of two-stage joints can be practically disregarded in the determination of heat requirements.

Describes how a family of simulated neutral atmospheric surface layers was used to determine the response of the wind loads on a building model, as well as the associated flowfield near it, to variations in the characteristics of these 'test boundary layers'. Results include the variation in the size of the horse- shoe vortex at the base of the building, spectra of pressure fluctuations, and documented variations in the wake Strouhal frequency with changing boundary layer characteristics.

Refers to earlier work by Mattingly, Peters, Harrje and Heisler which indicated the possibility of reducing air infiltration by using sheltering devices such as fences, neighbouring buildings and trees. Reports use of wind tunnel air infiltration model to explore the effect of trees in a windbreak on a model home. Presents results of tests determining the effect on wind-induced air infiltration of the variation of various windbreak layout parameters. Introduces concept of turbulence generation as the mechanism of tree wind sheltering.

Describes typical town centre developments in which a problem of wind environment has arisen, and gives a brief account of the investigation of specific cases. Summarises broad conclusions of 20 special cases. Describes series of investigations intoair-flow around small groups of idealised model buildings and compares model with full-scale measurements. Outlines design method for use in planning layout of small groups of buildings. Discusses future research needs.

Gives results of measurements of air-change rates and heat loss in occupied and unoccupied houses on two sites, one exposed and the other sheltered. Observations of the wind pressures on the houses and of the window-opening habit of the occupants are discussed. These are used in conjunction with the results of a regional survey of the temperatures maintained and the window-opening habits in local authority houses to extend the application of the results of other housing.

Describes wind tunnel measurements made on a model of a tall building surrounded by lower buildings under various combination of wind speed, wind angle and air temperature. Gives method for calculation of air infiltration rates and describes the computer program used. Concludes that air infiltration is a strong function of wind direction. Finds that maximum air infiltration was produced by a wind that approached at 0 deg and the minimum air infiltration occurred at 75 deg wind angle.

Discusses control from outdoors and gives a formula for the heat required to maintain indoor design temperatures. Outlines the twofold effect of wind, i.e. the increase in the heat transmission coefficient for outside walls, and increased ventilation and air infiltration caused by pressure differences. Explains the solar effect by formulating the heat load on the outer walls and through the windows. An example illustrates the calculation procedure. Tabulates the increase in heat consumption due to wind; this varies with wind speed, building location and height.

A number of cases of water and frost damage in masonry and non loadbearing walls have been examined. This damage could not have resulted from vapour diffusion or rain penetration and is primarily caused by condensation due to exfiltration of air. Air exfiltrates through the many cracks and joints and in this connection the result of chimney action and wind is explained in some detail, including the pattern and magnitude of building pressure differences that induce ex-filtration together with a discussion regarding the moisture that is transferred.

Using nitrous oxide as a tracer, the author made 390 measurements of ventilation rates in seven closed rooms of six houses, in Melbourne, Australia. Half of the observations were taken when the wall ventilators were sealed, in order to explore their influence on room ventilation. Results for each room, grouped in ranges of wind direction and according to whether ventilators were open or closed, are shown as regression curveson plots of ventilation rate against wind speed. The ventilators are shown to have only a slight effect on ventilation.

Presents a general picture of the consequence of wind on high buildings. States that the air velocity in the lower 250-600m layer of the atmosphere is strongly affected by the shape of the earth's contours, and discusses the effect and size of eddies. Gives the range of wind pressure variations between windward side, leeward side and at corners and edges and outlines problems that can result in ventilating, from draught and other wind hindrance aspects. Brief tips are given to minimize serious mishaps from the result of wind near high rise buildings.