Omri Ram

Zuckerman Faculty Scholar Omri Ram published Shock propagation through a local constriction in the Journal of Fluid Mechanics. Dr. Ram leads the Transient Fluid Mechanics Laboratory in the Faculty of Mechanical Engineering at Technion – Israel Institute of Technology. Using high-fidelity simulations, Dr. Ram’s research team examined shock-wave propagation through narrowed tube sections to quantify how constriction geometry influences reflected and transmitted shock strength. The analysis provides detailed predictions for both abrupt and smooth constrictions. These results can inform the design of propulsion systems, internal-flow components, and industrial piping where shock waves may affect safety or performance.

Abstract:
The interaction of a shock wave with a localized constriction in a straight conduit is investigated by systematically varying the blockage ratio in the range 0.35-0.75, the normalized constriction length in the range 0.25-2, and the incident Mach numbers of 1.4 and 1.8. Abrupt rectangular constrictions and smoothly contoured sinusoidal constrictions are considered, as they provide two limiting configurations. Validated Large-eddy simulations resolve both the transient start-up dynamics and the subsequent propagation of reflected and transmitted shock waves. The results show that, for rectangular constrictions, the reflected shock strength depends primarily on the blockage ratio and is largely independent of length, whereas the transmitted shock exhibits measurable sensitivity to constriction length. In contrast, sinusoidal constrictions display a strong coupling between blockage and length, with the reflection process governed by the local contour slope and evolving reflection topology.