Richard Raspet's legacy in porous media and thermoacoustics

Richard Raspet significantly advanced the fields of sound propagation in porous media and thermoacoustics, bridging these domains through innovative research. His seminal work unified Biot's theoretical framework for porous media with Rott's thermoacoustic theory, allowing comprehensive modeling of sound propagation and energy flow in pores with various geometries. Raspet's insights revealed the interplay between thermoviscous dissipation functions and established a universal methodology for applying porous media models to thermoacoustics. This framework supported advancements in thermoacoustic devices, including engines and refrigerators, by enabling the use of random and fibrous media such as fiberglass and metallic foams. Furthermore, Raspet pioneered the exploration of evaporation–condensation effects, demonstrating their critical role in enhancing thermoacoustic efficiency and energy density, leading to patented innovations. His contributions laid a foundational understanding that continues to propel both theoretical and applied research in acoustics, earning him recognition as a transformative figure in physical acoustics.