Control of laminar separated bubbles using an adaptive mechanical turbulator

Abstract

An experimental study of the actuation and sensing in a two-dimensional laminar separation bubble flow has been conducted. The laminar separation bubble is caused by the adverse pressure gradient that is imposed on a laminar boundary layer flow over a flat plate. The use of an adaptive mechanical turbulator, which is actuated using a shape memory alloy mechanical system, to control the laminar separation bubble flow is examined. The use of surface-mounted hot-film sensors to detect the locations of separation, transition and reattachment in the laminar separation bubble flow is also studied. The hot-film sensors are operated using a multichannel constant voltage anemometer system. The adaptive mechanical turbulator is found unsuitable for proportional control of the laminar separation bubble flow. The statistical moments of the output from the hot-film sensors provide reliable indicators of the separation and transition. These experimental measurements are verified by the results from numerical simulations.