Related Experiment Video
Updated: Aug 26, 2026

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Giant and anomalous Doppler effect, negative transmission and meta-like interaction between an acoustical wave and a
Ronan Delalande1,2, Mathieu Ducousso2, Guillaume Musy1
1Sorbonne Université, Centre National de la Recherche Scientifique, Institut Jean Le Rond d'Alembert, F-75005 Paris, France.
Abstract:
The interaction of a weak shock wave in a fluid with an incident sound wave is investigated, either in the counter- or co-propagating cases. This last situation is possible because the shock wave moves supersonically and overcomes the sonic sound wave. For a sustained shock, the problem can be solved analytically by introducing a transmitted sound wave, a vorticity mode and an entropy mode in the post-shock region, and a perturbation of the shock front. Due to the relative motions of the shock and the incident wave, a Doppler effect occurs. The analysis of the eight possible regimes of interaction outlines the influence of the shock strength. For an intermediate range of angles, transmitted waves are observed. For the highest incidence angles in the co-propagating case, the transmitted wave is propagative again but exhibits meta-like properties similar to those searched for in artificial meta-materials. These properties are negative transmission, or reversal of the direction of the transmitted wave along the shock front, and anomalous Doppler effect (Doppler ratio smaller than unity).
Related Concept Videos
Shock Waves
When the source's speed approaches the speed of sound, constructive interference between successive wavefronts emitted by the source occurs immediately behind it. Initially, scientists believed that this constructive interference would result in such high pressures...
Doppler Effect - II
Sound Waves: Interference
Doppler Effect - I
Interference and Diffraction
Interference and Superposition of Waves
Interference occurs in mechanical waves, such as sound waves, waves on a string, and surface water waves. Mechanical waves correspond to the physical displacement of particles. Hence,...

