Document Type
Article
Publication Date
4-2-2025
Abstract
This experimental investigation focuses on understanding the influence of perturbations due to short-duration energy deposition on the shock train structure and flow dynamics in an axisymmetric over-expanded Mach 2.52 jet. The flow is perturbed by localized laser-induced breakdown at various locations within the jet, creating a shock wave and a high-temperature plasma zone in the shock train. A high-speed self-aligning focusing schlieren system is used to visualize the flow and characterize the shock train dynamics and the flow structure recovery process by measuring the distance to the first shock reflection point from the nozzle exit. The response of the jet flow is similar for cases with the perturbation at the nozzle exit and the pre-reflection point across a range of jet total pressures, but the response is qualitatively different when the perturbation occurs downstream of the first shock reflection in the jet, with the flow structures being forced upstream toward the nozzle. The frequency of the oscillations of the shock height is found to be the same for all cases, approximately 10 kHz, independent of the jet total pressure, laser energy, and deposition location. The oscillations reduce in magnitude over time, and the damping ratio for cases with the energy deposition at the pre-reflection point and nozzle exit is found to be nearly constant with respect to jet total pressure and deposition energy, varying within the range of 0.06–0.12, whereas it is dependent on the jet chamber pressure for the post-reflection case, varying from 0.07 to 0.14.
Publication Title
Experiments in Fluids
Rights
© The Author(s) 2025. This is an Open Access work distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Syam, S., Jassal, G.R. & Schmidt, B.E. An experimental investigation on the effect of laser energy deposition in an over-expanded jet. Exp Fluids 66, 82 (2025). https://doi.org/10.1007/s00348-025-04008-x
Manuscript Version
Final Publisher Version