The effect of aspect ratio on the wake of the Ahmed body

Abstract

This paper seeks to further elucidate the wake of the Ahmed body by investigating how the time-averaged flow structures vary with frontal aspect ratio. High-resolution particle image velocimetry results are provided for eight different width Ahmed geometries at (Formula Presented.). It is shown that the narrower the body, the greater the downwash over the back slant, meaning the flow remains more attached. At a critical aspect ratio ([InlineMediaObject not available: see fulltext.] = 1.9), the flow downstream changes. The separation over the back slant is shown to be affected by the [InlineMediaObject not available: see fulltext.], and this in turn has a significant effect on the circulation in the c-pillar vortices.