Turbulence generation by shock interaction with a highly nonuniform medium
Abstract
An initially planar shock wave propagating into a medium of nonuniform density will be perturbed, leading to the generation of postshock velocity perturbations. Using numerical simulations we study this phenomenon in the case of highly nonuniform density (orderunity normalized variance, σ_{ρ}/ρ ¯∼1 ) and strong shocks (shock Mach numbers M_{¯s}≳10 ). This leads to a highly disrupted shock and a turbulent postshock flow. We simulate this interaction for a range of shock drives and initial density configurations meant to mimic those which might be presently achieved in experiments. Theoretical considerations lead to scaling relations, which are found to reasonably predict the postshock turbulence properties. The turbulent velocity dispersion and turbulent Mach number are found to depend on the preshock density dispersion and shock speed in a manner consistent with the linear RichtymerMeshkov instability prediction. We also show a dependence of the turbulence generation on the scale of density perturbations. The postshock pressure and density, which can be substantially reduced relative to the unperturbed case, are found to be reasonably predicted by a simplified analysis that treats the extended shock transition region as a single normal shock.
 Publication:

Physical Review E
 Pub Date:
 June 2022
 DOI:
 10.1103/PhysRevE.105.065206
 arXiv:
 arXiv:2205.15998
 Bibcode:
 2022PhRvE.105f5206D
 Keywords:

 Physics  Plasma Physics;
 Physics  Fluid Dynamics
 EPrint:
 15 pages, 10 figures