The response of a nearly supercritical pure fluid to a thermal disturbance

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Abstract
The response of a nearly supercritical pure fluid confined in a slablike container to a slowly varying temperature disturbance at the boundary is studied. The matched asymptotic expansion technique is used to describe the core and boundary‐layer flows on the short acoustic time scale. The multiple scale expansion technique is then used to obtain the solution of the equations for longer times. It is found (i) that the acoustic field generated in the bulk is stronger, the closer the initial conditions are to the critical point; (ii) that the heat transport is much faster than the conductive transport owing to the very high compressibility of the fluid; (iii) the scaling laws and the equations describing the flow field on the long time scale confirm both the numerical results obtained previously as well as their interpretation in terms of the piston effect which provokes the enhancement of the heat transport by adiabatic compressive heating of the bulk phase.