modelling

Presents the results of a series of wind tunnel tests in which the surface pressure fields of low-rise buildings have been studied. These tests start with an examination of how the body shape influences the surface pressures for a range of isolated bodies. The test results then go on to describe how theparameters which describe an array of such model buildings influence the surface pressures.

Reports a systematic investigation of the wind pressure variations when test models of varying height are surrounded by uniform roughness arrays of various densities in a boundary layer wind tunnel. Describes the effect of the surrounding roughness in shielding the bluff model when the model height is less than the average roughness height and of the degree of exposure experienced by a model taller than the surrounding roughness. Discusses results and gives 24 graphs of pressure coefficients.

Continues an investigation of surface pressures on models in a boundary layer wind tunnel. Part One gave results of measurements on isolated models, Part Two considered the same models in arrays of various densities. Gives vertical distribution of pressure coefficients measured on the centre line of windward and leeward faces of all the models in various layout densities. Discusses the effects of varying layout density, aspect ratio and roughness fetch. Includes 64 graphs of pressure coefficients.

Briefly surveys past work on wind tunnel measurements on the surface pressures on low rise buildings. Describes experimental investigation of the surface pressures on an isolated model. Discusses results of flow around a model of varying height and aspect ratio, and the influence of upstream fetch on surface pressures. Gives figures showing recorded pressure coefficients and details of pressure tappings on the various models.

Reports a program of research in progress at the Colorado State University to determine the surface pressures on building models immersed in a simulated atmospheric flow. Pressure data on a model building is taken from 272 tappings and reduced to pressure coefficients. Reports pressure coefficient measurements have been completed for 23 building/boundary layer combinations.

Investigates use of an array of spires, located at the entrance to the working section of a conventional wind tunnel, as a means of generating thick shear layers with properties similar to those of the neutrally-stable atmospheric wind. Compares data obtained in the shear layers created by sucharrays of spires with some available atmospheric data. Modifications to thespire design and a range of spire sizes have been tested and the resulting shear layer properties compared.

Presents further measurements of wind pressures on models of the experimental Aylesbury house of the Building Research Establishment (U.K.). following a previous paper in which mean pressure coefficients only were compared, this stud compares fluctuating pressures as well. In these tests, the upwind hedges of the full scale site were modelled, but found to cause little difference to the velocity profiles and to the measured pressures.

Discusses the two methods for calculating air infiltration given in the ASHRAE handbook. These are the air change method, a gross estimate based on the number of windows and doors in each room, and the crack method based on measurements of flow through the cracks around windows and doors. Presents comparisons of tracer gas measurements with calculations by both air change and crack methods for test houses in California and Minnesota. Find agreement is adequate for sizing equipment but that the crack method underestimates infiltration at low wind velocity.

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

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.