Transition to Turbulence in a Pulsatile Pipe Flow : 3rd Report, Flow Regimes and the Conditions Describing the Generation and Decay of Turbulence

Abstract

Pulsatile pipe flows are classified into four categories, such as laminar, transitional, conditionally turbulent, and fully turbulent flows. The limits between these four flows are determined experimentally as functions of the dimensionless frequency, time-averaged Reynolds number, and Reynolds number based on the velocity amplitude. The conditions describing the generation and decay of turbulence can be specified in the present experimental range by the parametric criterion K introduced for an accelerating steady flow. This fact implies that there exists a similarity between the effects of spatial acceleration and temporal one on the onset ofrelaminarization as well as the occurrence of turbulent bursting.