In this paper we consider the effect of dynamical correlations on the
absorption of energy by a gas of mutually noninteracting particles ins
ide a container whose shape changes slowly (and periodically) with tim
e. Tn principle, such correlations can significantly alter the rate at
which energy is absorbed by the gas. We present the results of numeri
cal simulations in which this effect is clearly seen, and study the de
pendence of the effect on the rate at which the shape of the container
oscillates.