Modal interactions between a large-wavelength inclined interface and small-wavelength multimode perturbations in a...

Area of Science:

• Fluid dynamics
• Plasma physics
• Computational physics

Background:

• The Richtmyer-Meshkov instability (RMI) is a fundamental fluid instability occurring when a shock wave accelerates a perturbed interface between two fluids.
• Understanding RMI is crucial for fields like inertial confinement fusion and astrophysics.
• Previous studies often focused on single perturbation types or 2D simulations.

Purpose of the Study:

• To investigate the interaction between small-wavelength multimodal and large-wavelength inclined interface perturbations in reshocked RMI.
• To analyze the influence of initial perturbation characteristics on mixing and turbulence development.
• To validate simulation code against experimental data.

Main Methods:

• Three-dimensional simulations using the ares code.
• Code validation through comparison with experiments at the Georgia Tech Shock Tube facility.
• Analysis of simulation results for four cases with varying perturbation amplitudes and types.

Main Results:

• The flow retains a memory of initial conditions before reshock, affecting both entrainment and mixing.
• After reshock, the flow transitions to a turbulent-like state.
• High-amplitude large-wavelength perturbations can induce small-scale mixing similar to small-wavelength perturbations.

Conclusions:

• Initial perturbation characteristics significantly influence RMI evolution and resulting turbulence.
• The flow exhibits memory effects of initial conditions even after reshock.
• Large-wavelength perturbations, particularly at high amplitudes, play a critical role in generating small-scale turbulent features.