Journal of Fluid Mechanics

Table of Contents - Volume 700 - 2012  

Papers

Swept-wing boundary-layer receptivity

David Tempelmanna1 c1, Ardeshir Hanifia1a2 and Dan S. Henningsona1

a1 Linné Flow Centre, SeRC, KTH Mechanics, SE-100 44 Stockholm, Sweden

a2 Swedish Defence Research Agency, FOI, SE-164 90 Stockholm, Sweden

Abstract

Adjoint solutions of the linearized incompressible Navier–Stokes equations are presented for a cross-flow-dominated swept-wing boundary layer. For the first time these have been computed in the region upstream of the swept leading edge and may therefore be used to predict receptivity to any disturbances of the incoming free stream as well as to surface roughness. In this paper we present worst-case scenarios, i.e. those external disturbances yielding maximum receptivity amplitudes of a steady cross-flow disturbance. In the free stream, such an ‘optimal’ disturbance takes the form of a streak which, while being convected downstream, penetrates the boundary layer and smoothly turns into a growing cross-flow mode. The ‘worst-case’ surface roughness has a wavy shape and is distributed in the chordwise direction. It is shown that, under such optimal conditions, the boundary layer is more receptive to surface roughness than to incoming free stream disturbances.

(Received November 07 2011)

(Reviewed January 26 2012)

(Accepted March 20 2012)

(Online publication April 18 2012)

Key Words:

  • boundary layer receptivity

Correspondence:

c1 Email address for correspondence: david@mech.kth.se

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