Direct numerical simulation and inviscid linear analysis are used
to
study the interaction of a normal shock wave with an isotropic turbulent
field
of vorticity and entropy fluctuations. The role of the upstream entropy
fluctuations is emphasized. The upstream correlation between the vorticity
and
entropy fluctuations is shown to strongly influence the evolution of the
turbulence across the shock. Negative upstream correlation between
u′ and T′ is seen to enhance the amplification
of the
turbulence kinetic energy, vorticity and thermodynamic fluctuations across
the shock
wave. Positive upstream correlation has a suppressing effect. An explanation
based
on the relative effects of bulk compression and baroclinic torque is proposed,
and a
scaling law is derived for the evolution of vorticity fluctuations across
the shock.
The validity of Morkovin's hypothesis across a shock wave is examined.
Linear
analysis is used to suggest that shock-front oscillation would invalidate
the
relation between urms and
Trms, as expressed by the hypothesis.
Hybridizing Multi-pass and Multi-plate Bulk Compression