DYNAMICAL CHARACTERISTICS OF WAVE-EXCITED CHANNEL FLOW

This paper is part of a study on the receptivity characteristics of th e shear flow in a channel whose walls are subjected to a wave-like exc itation. The small amplitude forced wavy wall motion is characterised by a wave number vector lambda1, lambda2 and a frequency omega(g). The basic flow in the problem is a superposition of the Poiseuille flow a nd a periodic component that corresponds to the wave excitation of the wall. The aim of the study is to examine the susceptibility of this f low to transition. The problem is approached through studying the stab ility characteristics of the basic flow with respect to small disturba nces. The theoretical framework for this purpose is Floquet theory. Th e solution procedure for solving the eigenvalue problem is the spectra l collocation method. Preliminary results showing the influence of the amplitude and the wave number of the wall excitation on the stability boundary of the flow are presented.