Description:
<jats:p>The leading-edge receptivity to acoustic waves of two-dimensional bodies is investigated
using a spatial solution of the Navier–Stokes equations in vorticity/stream
function form in general curvilinear coordinates. The free stream is composed of a
uniform flow with a superposed periodic velocity fluctuation of small amplitude. The
method follows that of Haddad & Corke (1998), in which the solution for the basic
flow and the linearized perturbation flow are solved separately. The initial motivation
for the work comes from past physical experiments for flat plates with elliptic leading
edges, which indicated narrow frequency bands of higher neutral-curve Branch I
receptivity. We investigate the same conditions in our simulations, as well as on a
parabolic leading edge. The results document the importance of the leading edge,
junction between the ellipse and flat plate, and pressure gradient to the receptivity
coefficient at Branch I. Comparisons to the past experiments and other numerical
simulations showed the influence of the elliptic leading-edge/flat-plate joint as an
additional site of receptivity which, along with the leading edge, provides a wavelength
selection mechanism which favours certain frequencies through linear superposition.</jats:p>