wind tunnel

Shows that the interior pressures in buildings are amenable to more detailed analysis than is conventionally given them and that useful information on them can be easily derived from the wind tunnel data on external pressures. The uncertainties can be expressed in parallel statistical terms. The importance of fluctuating pressures are related to the area of the opening and interior volume and a simple criterion indicates when these are likely to be important.

An experiment was indertaken in order to explore sensitivity of measured pressures to the accuracy with which the terrain and boundary layer winds are modelled. A 1:100 scale model was tested for a single roof pitch and wind angle and eight different boundary layer simulations. The experiment was conducted as part of a review of the reliability of wind tunnel test data when compared with full scale experiments, such as those carried out by the Building Research Establishment at Aylesbury.

Tests a large office building, consisting of several octagonal towers and other blocks in a boundary layer wind tunnel. Determines the highest suction pressures which are relevant for the fixing of the cladding. Uses a tracer gas method to determine recirculation problems of the ventilation system inlets and outlets resulting from the arrangement of octagonal towers of different heights. Wind velocities on the flat roof of some towers are studied by meansof an erosion technique using flour, checks the accuracy of the method using hot wire measurements.

The estimation of the average wind pressures on buildings can be made via wind tunnel measurements. Carries out measurements on 5 models of buildings under various conditions. With the aid of these results and some interpolation, makes a prediction of the average wind pressure for a large number of buildings. Includes studies of the effects on the pressure caused by another building upwind.

Studies the effects of permeability on the wind loading on a building. Compares experimental results from wind-tunnel tests with theoretical methods for estimating the mean and fluctuating internal pressures for various permeability. Observations show that the internal pressure can be estimated from known external conditions in terms of mean RMS and spectral values to a reasonable level of accuracy for the case where the permeability consists of circular apertures. Effects on the external pressure distribution due to permeability are found to be significant under certain circumstances.

A wind-tunnel model study of the experimental building at Aylesbury, England has been conducted at scales of of 1:25, 1:50 and 1:100. Compares model results with those obtained in other wind-tunnel studies and with full-scale values obtained by the Building Research Establishment at Aylesbury.

Describes a study to map the ground wind conditions in the housing area Kroksback in Malmo, and to study the effect of various proposed measures to improve the wind environment. Studies local ground wind conditions by field measurements using the Swedish Institute for Building Research (SIB) mobile measuring unit and by comparative model tests in the SIB wind tunnel laboratory. Estimates wind speed and direction by means of a simple indicator device.

Compares wind pressures measured on a 1:25 scale model of a mobile home with results from a full-scale investigation. The modelling technique used exaggerates the surface roughness in order to match the full-scale turbulence intensity at the model height. Shows that there is reasonable agreement of themean and RMS pressure coefficients between model and full scale, when the pressure coefficients are normalized by the local dynamic head at the building height.

Uses wind tunnel model studies of houses to determine how best to reduce the surface pressure variations from wind and the associated air infiltration emphasizing the correct placement of suitably modelled coniferous trees. Finds that tree crowns convert the directed kinetic energy of approaching wind into random turbulent energy, which reduces pressure gradients on the windward walls, a prime region for air infiltration.

Describes a scale model test technique designed to estimate building ventilation flow rates due to wind as a function of its primary variables. Use of this method is illustrated by its application to the determination of wind-induced ventilation flow rates in earth-bermed, above-ground fallout shelters. Shelter models with 3 different sets of wall openings are tested over a range of relative wind angles varying from 0 to 90 degrees and wind speeds from 2.25 m/s to 6.75 m/s. Helium filled soap bubbles released in the approach wind boundary layer trace the flow through the buildings.