Experimental study of statistical and spectral characteristics of wake flow around the rear view side mirror of a passenger car

In order to study the turbulent structure of wake flow around the rear view side mirror of a passenger car, moment property and energy spectra in the mirror wake and fluctuating pressure distribution on the mirror surface have been measured by several experimental tools in an open circuit wind tunnel at the Reynolds number of 2 × 105. It was found that time-averaged streamwise velocity very near the tip region of the mirror housing was accelerated, and the recirculation zone was observed up to 1.2d downstream of the mirror. Also, peak values of rms fluctuation velocity appeared in the edge of the mirror wake due to significant vortex shedding. The corresponding skewness and kurtosis factors were deviated from a Gaussian distribution. It was also found that dominant energy of vortex shedding in the near mirror wake appeared behind side tip region of the mirror surface. Vortex shedding frequency behind outside edge of the mirror housing has lower values than those of the upper and lower edges of the mirror housing. It was concluded that strong turbulent energy at the near wake was induced by significant vortex shedding having non-random characteristics, resulted in intermittent force around tip region of the mirror surface.