Experimental study on the Rayleigh–Taylor instability of metallic interfaces with dual-mode driven by explosion

Abstract

Planar detonation-driven experiments and numerical simulations were combined to investigate the evolution of Rayleigh–Taylor instability at copper interfaces under single-mode and dual-mode initial perturbations. A planar wave lens was used to drive a high-energy explosive, achieving quasi-isentropic loading on oxygen-free copper (grade TU1) with purity greater than 99.97% through a 3.5 mm gap, with peak pressures ranging from 34 to 37 GPa. Simultaneously, x-ray images of the sample profile with a time resolution of less than 100 ns and free surface Doppler Pins System velocity histories with a sampling interval of 0.5 mm were acquired. Explicit dynamics numerical simulations, employing the Steinberg–Guinan (SG) constitutive model for the experimental samples, were integrated to quantitatively characterize perturbation development. The results indicate that the free surface velocity at the trough of dual-mode perturbations is significantly higher than that of single-mode perturbations, and pressure convergence in the peak region induces multiple jumps in free surface velocity. The growth of perturbation amplitude at the loading surface during dual-mode coupling shows good agreement between numerical simulations and x-ray images, with the SG constitutive model accurately predicting amplitude development with error less than 5%. The thickness of the specimen shows an obvious stabilization effect, and there is a critical value for the thickness. Reducing the initial wavelength and increasing the initial amplitude both accelerate the growth of perturbations on the loading surface. The initial amplitude is the core factor controlling the development of dual-mode perturbations.