Reynolds stress budgets of low Reynolds number pipe expansion flow

Abstract

The turbulent flow in a sudden pipe expansion is of theoretical and practical importance. Although the flow domain is quite simple and the separation point is fixed at the step, the flow itself is complex and its accurate prediction remains a challenge for turbulence modellers still today. Its complexity is due to the appearence of a mixing layer, a recirculation and a reattachment zone. Flow of this type occurs in engines, heat exchangers, sudden-expansion dump combustors and numerous other applications so that the understanding of its physics is a prerequisite of efficient engineering design and theoretical prediction.