Simulations and models for the Richtmyer– Meshkov instability with broadband perturbations

Technical Report · Tue Feb 20 04:00:00 EST 2024

DOI:https://doi.org/10.2172/2386901· OSTI ID:2386901

Dimonte, Guy ^[1]; Nagori, Madhav ^[2]; Ramaprabhu, Praveen ^[2]; Djibrilla Boureima, Ismael ^[1]

---

1. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
2. Univ. of North Carolina, Charlotte, NC (United States)

The Richtmyer–Meshkov instability (RMI) is shock driven and affects many phenomena from inertial fusion to supernova explosions. The behavior of single-modes in the RMI has been studied extensively but less is known with the broadband perturbations that occur in applications. Here, we describe extensive numerical simulations and modeling of the RMI with broadband perturbations with an initial power spectrum of the form P∝ k^m, where k is the wavenumber. The hydrodynamic condition is the same as in the $$\theta$$-Group Collaboration [Thornber et al., “Late-time growth rate, mixing, and anisotropy in the multimode narrowband Richtmyer–Meshkov instability: The $$\theta$$-group collaboration,” Phys. Fluids 29, 105107 (2017)] with a Mach ~1.86 shock and gamma-law = 5/3 fluids with Atwood number A = 0.5. The bubble amplitude h_B is found to grow in two stages. Initially, h_B undergoes a phase-inversion and grows linearly in time (t) at a rate consistent with a linear theory. Asymptotically, h_B grows as a power law $$~t^{\theta}$$ when $$\langle{k}\rangle{|h_B|}$$ > O(1), where $$\langle{k}\rangle$$ is the average wavenumber for the initial spectrum. The RMI behavior in simulations and modeling agree over a wide range of exponent m, spectral width, initial amplitude, and time. The agreement is quantified objectively using statistical analysis.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• DOE Contract Number: 89233218CNA000001
• OSTI ID: 2386901
• Report Number(s): LA-UR--23-32285
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY