Car-Wake Imaging Using a Seven-Hole Probe

Abstract

<div class="htmlview paragraph">This paper illustrates an advanced technique recently introduced in the Pininfarina wind tunnel for surveying the flow field of full-scale passenger cars.</div> <div class="htmlview paragraph">The technique is based upon the use of a non-nulling seven-hole probe, which is traversed continuously by a fast traversing system. The traversing system moves in the flow field under computer control.</div> <div class="htmlview paragraph">Planar surfaces of various preselected sizes can be surveyed with corresponding wind tunnel run times ranging from 5 to 40 minutes. As a result of a single planar survey, local pressures and velocities are mapped on a computer colour-display output.</div> <div class="htmlview paragraph">Usually, four colour maps are generated to show and summarize the distribution of total and static-pressure coefficients and total and cross-flow velocities.</div> <div class="htmlview paragraph">This technique is used mainly to investigate body wakes.</div> <div class="htmlview paragraph">Several examples regarding passenger cars or models, as well as an isolated formula-one type rear wing, are reported.</div> <div class="htmlview paragraph">Information provided by this technique, as well as its limitations, are shown.</div> <div class="htmlview paragraph">Interesting information is also obtained when the same technique is employed in flow fields other than the wake of a body.</div> <div class="htmlview paragraph">As an example, maps of pressures and velocities measured in front of various bodies are reported.</div>