Particle Tracking Velocimetry in Transitional Plane Couette Flow

Abstract

Plane Couette flow has the peculiar property that transition to turbulence occurs despite the fact that its laminar profile is linearly stable. For high enough Reynolds numbers small amplitude perturbations are enough to initiate the growth of turbulent spots. Such spots have been subject to investigation for a few decades, see e.g. [1, 2]. In addition, it has been observed that around transitional Reynolds numbers laminar and turbulent regions can co-exist if this Reynolds number is approached from the turbulent side, e.g., [3, 4]. For both cases, distinct interfaces divide the regimes between turbulent and non turbulent flow. It is our main interest to study the evolution of such interfaces similar to the work of [5] where the shear free case with inhomogeneous forcing by an oscillating grid has been investigated in detail.