  When a gas in an externally imposed potential field is compressed,
temperature gradients appear. This has been called the piezothermal effect. It
is possible to analytically calculate the time-dependent behavior of the
piezothermal effect using a linearized fluid model. Quantitative differences
between the fluid-model results and previous numerical calculations can be
explained by the effects of viscosity and heat conductivity. The fluid model
casts the piezothermal effect as a spectrum of buoyancy oscillations, which
yields new physical insights into the effect.
