wind

Reports measurements of pressure distribution on square cylindrical models in wind tunnel. Vertical distribution of wind velocity was produced by grids of horizontal rods at varying spacing. Wind pressure distributions on model-scale buildings were obtained, varying the height, width, depth and winddirection. To compare results, a large-scale model 3.6 metreshigh 1.2 metres by 1.2 metres in plan was placed on the shore and pressure distribution measured during a strong wind. Gives diagrams of pressure distributions.

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 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.

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.

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

Describes both the macro and micro meteorological structure of strong winds in the earths boundary layer. Discusses the wind speed spectrum, characteristics of mean flow and gustiness and the structure of turbulence. Concludes that almost all theproperties of the wind that might be needed in structural design can be estimated from the mean-wind field and the groundroughness. Suggests areas for further research.

Gives short state-of-the-art review of knowledge of wind turbulence. Mentions results from field investigations. Summarizes available knowledge. An appendix discusses hot-wire anemometry. Gives bibliography of subject.

Discusses the problems of modelling natural wind in a wind tunnel and notes lack of comparison between full-scale and wind tunnel studies. Reviews past work which often shows marked discrepancies in wind tunnel data. Reports results of a study carried out in the field of wind effects on a half full-size single storey model building. Wind profiles over the site were measured and pressure effects experienced by the model recorded.

This paper is a review of past and current research on the subject of wind loads. Topics discussed are present wind load requirements, the determination of basic design wind velocities, the structure of natural winds, wind-tunnel studies, gusts andthe vibration of structures. Gives recommendations for basic design wind velocities, increase of wind velocity with height,and formulation of shape and gust coefficients. Includes bibliography of 270 references.

Discusses the need for shelterbelts over farmland and gives expression for drag force exerted by a barrier in terms of air density, wind speed, barrier height and ratio of wind speed in the shelter to that in the open. Describes field study to determine the effect of a shelterbelt on vertical wind profiles. Presents two-dimensional wind reduction patterns in the lea of the shelterbelt. Calculates drag coefficients for the shelterbelt. Concludes that a shelterbelt can be very effectivein a very short period after planting.