Control of Crossflow Instability Field by Selective Suction System.

Abstract

A full turbulent transition process is created on a yawed flat plate using a displacement body system in a wind tunnel. It was found that high frequency secondary instability drives the crossflow dominant boundary layer into a full turbulent state. Taking into account such transition structures, effective control of the flow field to delay the transition is possible. That is, by placing grooving line suction holes along each streamwise crossflow vortex, and as is causing selective suction in the low momentum flow, the appearance of the secondary instability is successfully delayed turbulent transition. This suction system also has an advantage over a uniform system in that the amount of suction air volume required to control the flow field is much less than in uniform suction. Thus, a great deal of energy needed for flow control is saved. We also attempted to determine the most appropriate condition for selective suctioning.