Numerical Simulations of a Shock-Filament Interaction

TL;DR

This paper uses 3D hydrodynamic simulations to study how shock waves interact with dense, elongated filaments, revealing differences in morphology, acceleration, and mass loss compared to spherical clouds, depending on filament orientation and shock parameters.

Contribution

It provides new insights into the effects of filament shape and orientation on shock interaction dynamics, extending previous spherical cloud models.

Findings

Filaments form parallel vortex rolls and exhibit vortex shedding.

Sideways filaments accelerate faster and lose mass initially more rapidly.

Oblique filaments can reach transverse velocities up to 10% of shock speed.

Abstract

We present 3D hydrodynamic adiabatic simulations of a shock interacting with a dense, elongated cloud. We compare how the nature of the interaction changes with the filament's length and its orientation to the shock, and with the shock Mach number and the density contrast of the filament. We then examine the differences with respect to 3D spherical-cloud calculations. We find significant differences in the morphology of the interaction when M=10 and chi=100: in many cases 3 parallel rolls are formed, and spread further apart with time, and periodic vortex shedding can occur off the ends of oblique filaments. Sideways-on filaments are accelerated more quickly, and initially lose mass more quickly than spherical clouds due to their greater surface area to volume ratio. However, at late stages they lose mass more slowly, due to the reduced relative speed between the filament and the postshock flow. The acceleration and mixing timescales can vary by a factor of 2 as the filament orientation changes. Oblique filaments can achieve transverse velocities up to 10% of the shock speed. Some aspects of our simulations are compared against experimental and numerical work on rigid cylinders.