The hypersonic flow over a cavity is investigated. The time-dependent
compressible Navier-Stokes equations are numerically sloved. An implic
it algorithm, with a subiteration procedure to recover time accuracy,
is used to perform the time-accurate computations. The objective of th
e study is to investigate the effects of Reynolds number and cavity di
mensions. The comparison of the computations with available experiment
al data, in terms of time mean static pressure, heat transfer, and Mac
h number, show good agreement. In the computations large vortex struct
ures, which adversely affect the cavity flow characteristics, are obse
rved at the rear of the cavity. A self-sustained oscillatory motion oc
curs within the cavity over a range of Reynolds number and cavity dime
nsions. The frequency spectra of the oscillations show good agreement
with a modified semiempirical relation.