Interface-coupling effects in shock-driven multilayer fluid system
Phys. Rev. Fluids 11, 063902 – Published 25 June, 2026
DOI: https://doi.org/10.1103/2gxr-ydgy
Abstract
The shock-induced evolution of a multilayer fluid system featuring three distinct interfaces is investigated theoretically and numerically. This system exhibits not only adjacent-interface coupling but also significant cross-interface coupling, which substantially complicates the growth of interfacial perturbations. To isolate and elucidate the effects of both coupling mechanisms on the perturbation development at each interface, we develop an alternative linear analytical model. By imposing total transmission condition at the two downstream interfaces, reverberating waves within the layers are effectively eliminated, thereby isolating pure coupling effects. The study examines seven fluid layer configurations with varying initial thicknesses and amplitude combinations to validate the model and explore the influence of interface coupling on hydrodynamic instabilities. Both the initial amplitude and the interinterface distance are found to exert a bidirectional influence, either enhancing or suppressing, on interface development. Leveraging the model, a predictive framework is established to identify initial parameters that lead to amplitude growth stagnation at individual interfaces through tailored interface-coupling effects. These results provide valuable insights into complex interfacial instability mechanisms in multilayer systems and offer practical guidance for engineering applications involving shock-accelerated fluid layers.