Flow-Field Surveys Behind Three Squareback Car Models Using a New “Fourteen-Hole” Probe

<div class="htmlview paragraph">The flow-field mapping technique previously developed in the Pininfarina wind tunnel has further evolved during 1986.</div> <div class="htmlview paragraph">The former technique (1985), based on the use of a “seven-hole” probe, had two main limitations: <ul class="list disc"> <li class="list-item"><div class="htmlview paragraph">poor sensitivity at low speed (<8 m/sec.)</div></li> <li class="list-item"><div class="htmlview paragraph">incapability of measuring at flow angles greater than +− 70°</div></li> </ul></div> <div class="htmlview paragraph">Both these conditions often occur inside the near-wakes of passenger-car models.</div> <div class="htmlview paragraph">Therefore, wake maps (velocities and pressures) made in the past were largely incomplete in their inner parts.</div> <div class="htmlview paragraph">The new probe has a double “seven-hole” pattern and its performance exceeds that of two “seven-hole” probes used separately.</div> <div class="htmlview paragraph">It was developed during the fourth year of a research program aimed at providing new experimental information on reverse flows in automobile wakes, for use in developing improved computational fluid dynamic (CFD) techniques for automobiles.</div> <div class="htmlview paragraph">Reverse flows inside the near-wake of three full-scale squareback car models were investigated.</div> <div class="htmlview paragraph">One of these models is the same as was tested in the past. The other two differ slightly in their rear-end shape from the first one.</div> <div class="htmlview paragraph">The main characteristics of the new probe and its performance are presented and compared with the “seven-hole” probe.</div> <div class="htmlview paragraph">Furthermore, the maps of velocities and pressures measured in the wakes of the three squareback car models are reported.</div>