To observe surface flow and wake characteristics around the external rear-view mirror of a passenger car, a pressure scanning system and hot-wire anemometry were used. To confirm the flow pattern over the mirror skin and to understand the trail of the vortex sheet, the oil flow visualization technique. Pressure distributions over the mirror housing surface showed that the mean pressure coefficient had a high value near the stagnation point, and pressure values gradually decreased towards the trailing edge of the mirror housing. The pressure distribution on the mirror glass surface showed that a minimum pressure location was found at the outside edge of the mirror glass, which is an origin of the vortex sheet. In the velocity vector fields measured in cross-sectional planes, a conical vortex sheet was developed on the side window of the passenger car, making a large rotating vortex downstream. With increased inflow velocity, this proximity between the vortex wrap and the vehicle body skin was more apparent. This phenomenon suggests a vortex body frame interaction as another noise source in the mirror wake. Surface flow visualization showed separation lines near the edges of the mirror housing owing to an adverse pressure gradient. It was also found that several separation bubbles appeared on the flat bottom surface over the mirror housing, which indicates a complex flow condition under a reversed flow region caused by the leading edge of the bottom mirror housing. This visualization result was in good agreement with the pressure results. To understand the mirror wake of a passenger car thoroughly, additional aerodynamic characteristics such as frequencies and moment properties of the mirror wake should be measured. Future work is planned in this area.
Surface flow and wake characteristics of automotive external rear-view mirror
2011
9 Seiten, 9 Bilder, 16 Quellen
Aufsatz (Zeitschrift)
Englisch
Surface flow and wake characteristics of automotive external rear-view mirror
Kraftfahrwesen | 2011
|Surface flow and wake characteristics of automotive external rear-view mirror
SAGE Publications | 2011
|Surface flow and wake characteristics of automotive external rear-view mirror
Online Contents | 2011
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