skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Investigation of the Richtmyer-Meshkov instability

Abstract

The present research program is centered on the experimental and numerical study of the hydrodynamics of shock-accelerated spherical density inhomogeneities. These flows are part of a broader category of shock-induced mixing flows that play a critical role in the implosion of D-T pellets in laser-driven ICF experiments. For the past year, our work has consisted of both experimental and numerical activities which were presented at two conferences and resulted in the publication of one journal article and the submission of a second one. The papers from one of the conferences are inlcuded here.

Authors:
; ;
Publication Date:
Research Org.:
University of Wisconsin - Madison
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
901009
Report Number(s):
DOE/NA/26196-1
TRN: US0703037
DOE Contract Number:
FG52-06NA26196
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; HYDRODYNAMICS; IMPLOSIONS; INSTABILITY; PELLETS; RESEARCH PROGRAMS; Richtmyer-Meshkov instability; shock-induced mixing; interfacial fluid instability

Citation Formats

Riccardo Bonazza, Mark Anderson, and Jason Oakley. Investigation of the Richtmyer-Meshkov instability. United States: N. p., 2007. Web. doi:10.2172/901009.
Riccardo Bonazza, Mark Anderson, & Jason Oakley. Investigation of the Richtmyer-Meshkov instability. United States. doi:10.2172/901009.
Riccardo Bonazza, Mark Anderson, and Jason Oakley. Mon . "Investigation of the Richtmyer-Meshkov instability". United States. doi:10.2172/901009. https://www.osti.gov/servlets/purl/901009.
@article{osti_901009,
title = {Investigation of the Richtmyer-Meshkov instability},
author = {Riccardo Bonazza and Mark Anderson and Jason Oakley},
abstractNote = {The present research program is centered on the experimental and numerical study of the hydrodynamics of shock-accelerated spherical density inhomogeneities. These flows are part of a broader category of shock-induced mixing flows that play a critical role in the implosion of D-T pellets in laser-driven ICF experiments. For the past year, our work has consisted of both experimental and numerical activities which were presented at two conferences and resulted in the publication of one journal article and the submission of a second one. The papers from one of the conferences are inlcuded here.},
doi = {10.2172/901009},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Mar 19 00:00:00 EDT 2007},
month = {Mon Mar 19 00:00:00 EDT 2007}
}

Technical Report:

Save / Share:
  • The present program is centered on the experimental study of shock-induced interfacial fluid instabilities. Both 2-D (near-sinusoids) and 3-D (spheres) initial conditions are studied in a large, vertical square shock tube facility. The evolution of the interface shape, its distortion, the modal growth rates and the mixing of the fluids at the interface are all objectives of the investigation. In parallel to the experiments, calculations are performed using the Raptor code, on platforms made available by LLNL. These flows are of great relevance to both ICF and stockpile stewardship. The involvement of three graduate students is in line with themore » national laboratories' interest in the education of scientists and engineers in disciplines and technologies consistent with the labs' missions and activities.« less
  • The Richtmyer-Meshkov instability (RMI) is experimentally investigated using several different initial conditions and with a range of diagnostics. First, a broadband initial condition is created using a shear layer between helium+acetone and argon. The post-shocked turbulent mixing is investigated using planar laser induced fluorescence (PLIF). The signature of turbulent mixing is present in the appearance of an inertial range in the mole fraction energy spectrum and the isotropy of the late-time dissipation structures. The distribution of the mole fraction values does not appear to transition to a homogeneous mixture, and it is possible that this effect may be slow tomore » develop for the RMI. Second, the influence of the RMI on the kinetic energy spectrum is investigated using particle image velocimetry (PIV). The influence of the perturbation is visible relatively far from the interface when compared to the energy spectrum of an initially flat interface. Closer to the perturbation, an increase in the energy spectrum with time is observed and is possibly due to a cascade of energy from the large length scales of the perturbation. Finally, the single mode perturbation growth rate is measured after reshock using a new high speed imaging technique. This technique produced highly time-resolved interface position measurements. Simultaneous measurements at the spike and bubble location are used to compute a perturbation growth rate history. The growth rates from several experiments are compared to a new reshock growth rate model.« less
  • For flows that contain significant structure, high order schemes offer large advantages over low order schemes. Fundamentally, the reason comes from the truncation error of the differencing operators. If one examines carefully the expression for the truncation error, one will see that for a fixed computational cost that the error can be made much smaller by increasing the numerical order than by increasing the number of grid points. One can readily derive the following expression which holds for systems dominated by hyperbolic effects and advanced explicitly in time: flops = const * p{sup 2} * k{sup (d+1)(p+1)/p}/E{sup (d+1)/p} where flopsmore » denotes floating point operations, p denotes numerical order, d denotes spatial dimension, where E denotes the truncation error of the difference operator, and where k denotes the Fourier wavenumber. For flows that contain structure, such as turbulent flows or any calculation where, say, vortices are present, there will be significant energy in the high values of k. Thus, one can see that the rate of growth of the flops is very different for different values of p. Further, the constant in front of the expression is also very different. With a low order scheme, one quickly reaches the limit of the computer. With the high order scheme, one can obtain far more modes before the limit of the computer is reached. Here we examine the application of spectral methods and the Weighted Essentially Non-Oscillatory (WENO) scheme to the Richtmyer-Meshkov Instability. We show the intricate structure that these high order schemes can calculate and we show that the two methods, though very different, converge to the same numerical solution indicating that the numerical solution is very likely physically correct.« less
  • We present numerical evidence from two dimensional simulations that the growth of the Richtmyer-Meshkov instability is suppressed in the presence of a magnetic field. A bifurcation occurs during the refraction of the incident shock on the density interface which transports baroclinically generated vorticity away from the interface to a pair of slow or intermediate magnetosonic shocks. Consequently, the density interface is devoid of vorticity and its growth and associated mixing is completely suppressed.
  • OAK-B135 An experimental investigation of a shock-induced interfacial instability (Richtmyer-Meshkov instability) is undertaken in an effort to study temporal evolution of interfacial perturbations in the late stages of development. The experiments are performed in a vertical shock tube with a square cross-section. A membraneless interface is prepared by retracting a sinusoidally shaped metal plate initially separating carbon dioxide from air, with both gases initially at atmospheric pressure. With carbon dioxide above the plate, the Rayleigh-Taylor instability commences as the plate is retracted and the amplitude of the initial sinusoidal perturbation imposed on the interface begins to grow. The interface ismore » accelerated by a strong shock wave (M=3.08) while its shape is still sinusoidal and before the Kelvin-Helmhotz instability distorts it into the well known mushroom-like structures; its initial amplitude to wavelength ratio is large enough that the interface evolution enters its nonlinear stage very shortly after shock acceleration. The pre-shock evolution of the interface due to the Rayleigh-Taylor instability and the post-shock evolution of the interface due to the Richtmyer-Meshkov instability are visualized using planar Mie scattering. The pre-shock evolution of the interface is carried out in an independent set of experiments. The initial conditions for the Richtmyer-Meshkov experiment are determined from the pre-shock Rayleigh-Taylor growth. One image of the post-shock interface is obtained per experiment and image sequences, showing the post-shock evolution of the interface, are constructed from several experiments. The growth rate of the perturbation amplitude is measured and compared with two recent analytical models of the Richtmyer-Meshkov instability.« less