surface pressure

Ventilation produced by fluctuating pressure differences across a building appears to have received little attention . Such fluctuations are produced by gustiness of the wind or turbulence in the flow around a building. An experimantal study has been performed on a laboratory model to investigate unsteady flows through apertures simulating those in the fabric of a building .

This text contains comments to the poster presented at the 9th AlVC Conference in Gent, Belgium. The project under consideration in the poster (Climatological Data Transfer) is one of the numerous research fields of the Swiss ERL program (Energierelevante Luftströmungen in Gebaüde - Energy Relevant Air Flow in Buildings).

When carrying out pressure tests of models of multi-story buildings in The Boundary Layer Wind Tunnel, the external mean and RMS pressures are measured at 400 to 800 different locations over the building surface. The tests are originally carried out in order to determine the net wind loads for the design of cladding and glazing, but the results can also be used to estimate the internal pressures, and then calculate the air infiltration. Two mathematical models are used to estimate the wind-induced air infiltration in three multi-story buildings.

Describes a method to estimate differences in external pressure values between walls from known mean pressure coefficients on the facades and roof of the building in question and from the determination of wind values on the site and at the same height as the building.

Reliable surface pressure and indoor wind speed data from model buildings in boundary layer wind tunnels can only be expected if appropriate modeling parameters are considered carefully. Modeling parameters to examine when planning boundary layer wind tunnel studies of indoor airflow and external surface pressures due to wind are identified, and criteria for assessment are suggested.

Two techniques for estimating natural wind airflow through buildings for comfort cooling utilizing data derived from boundary layer wind tunnel studies are presented. One method is based on pressure and discharge coefficients. The other uses wind speed coefficients determined from model studies in a boundary layer wind tunnel.

The aerodynamic forces affecting wind and rain penetration of roofs are described. They are: 1 the wind and its turbulent nature, 2 the induced pressure field, 3 the air flows in contact with the roof and 4 the characteristics of the roof (internal pressure, permeability, structure, etc).