Some experimental techniques to detect transition in boundary layer flow

Abstract

In this work, in an attempt to quantify the extent of the transition region, some experimental techniques to detect the start and end of transition in boundary layer flows over solid surfaces are employed. The techniques considered are: the (surface) Pitot tube technique the hot-wire intermittency technique as used by Hachem and Johnson; and the hot-wire frequency spectrum method as demonstrated by Winoto and Low. The purpose of the present work is to test the effectiveness of these three techniques in detecting the transition region of a boundary layer developing on a flat plate under a mild favorable pressure gradient.