Supersonic turbulence in shock-bound interaction zones I: symmetric settings

Abstract

Colliding hypersonic flows play a decisive role in many astrophysical objects. In this paper, we look at the idealized model of a 2D plane parallel isothermal slab (CDL) and at symmetric settings, where both flows have equal parameters. We performed a set of high-resolution simulations with upwind Mach numbers, 5 < M_u < 90. We find that the CDL is irregularly shaped and has a patchy and filamentary interior. The size of these structures increases with l_cdl, the extension of the CDL. On average, but not at each moment, the solution is about self-similar and depends only on M_u. We find the root mean square Mach number to scale as M_rms ~ 0.2 M_u. Independent of M_u is the mean density, rho_m ~ 30 rho_u. The fraction f_eff of the upwind kinetic energy that survives shock passage scales as f_eff= 1 - M_rms^(-0.6). This dependence persists if the upwind flow parameters differ from one side to the other of the CDL, indicating that the turbulence within the CDL and its driving are mutually coupled. In the same direction points the finding that the auto-correlation length of the confining shocks and the characteristic length scale of the turbulence within the CDL are proportional. In summary, larger upstream Mach numbers lead to a faster expanding CDL with more strongly inclined confining interfaces relative to the upstream flows, more efficient driving, and finer interior structure relative to the extension of the CDL.

arXiv commentversion sent to publisher, final language/typo corrections made. 23 pages, 19 figures, accepted for publication in A&A, version with high quality color images can be found at http://www.astro.phys.ethz.ch/papers/folini/folini_p_nf.html

References in corpus (37)

• The Physics of Gamma-Ray Bursts
• Control of star formation by supersonic turbulence
• Unsteady Outflow Models for Cosmological Gamma-Ray Bursts
• Interstellar Turbulence I: Observations and Processes
• Rapid Formation of Molecular Clouds and Stars in the Solar Neighborhood
• The Energy Dissipation Rate of Supersonic, Magnetohydrodynamic Turbulence in Molecular Clouds
• Kinetic Energy Decay Rates of Supersonic and Super-Alfvenic Turbulence in Star-Forming Clouds
• The Universality of Turbulence in Galactic Molecular Clouds
• Thermal condensation in a turbulent atomic hydrogen flow
• Interstellar Turbulence II: Implications and Effects
• Turbulent Flow-Driven Molecular Cloud Formation: A Solution to the Post-T Tauri Problem?
• Nonlinear Instabilities in Shock-Bounded Slabs
• Molecular cloud evolution. I. Molecular cloud and thin CNM sheet formation
• Clouds as Turbulent Density Fluctuations. Implications for pressure confinement and spectral line data interpretation
• Formation of Structure in Molecular Clouds: A Case Study
• Physical vs. Observational Properties of Clouds in Turbulent Molecular Cloud Models
• Collapse and Fragmentation in Finite Sheets
• The Turbulent Interstellar Medium: Generalizing to a Scale-dependent Phase Continuum
• Density Power Spectrum of Compressible Hydrodynamic Turbulent Flows
• Power Density Spectra of Gamma-Ray Bursts in the Internal Shock Model
• Can Nonlinear Hydromagnetic Waves Support a Self-Gravitating Cloud?
• Is Thermal Instability Significant in Turbulent Galactic Gas?
• Low power BL Lacertae objects and the blazar sequence: Clues on the particle acceleration process
• The Field Condition: A New Constraint of Spatial Resolution in Simulations of the nonlinear Development of Thermal Instability
• Bipolar molecular outflows driven by hydromagnetic protostellar winds
• Non-radial instabilities of isothermal Bondi accretion with a shock: vortical-acoustic cycle vs post-shock acceleration
• Energetics of Tev Blazars and Physical Constraints on their Emission Regions
• Shock-Heated Gas in the Large Scale Structure of the Universe
• The Mass Spectra of Cores in Turbulent Molecular Clouds and Implications for the Initial Mass Function
• X-ray emission lines from inhomogeneous stellar winds
• The Dynamics of Radiative Shock Waves: Linear and Nonlinear Evolution
• Synthetic X-ray light curves of BL Lacs from relativistic hydrodynamic simulations
• The Effect of Light Scattering by Dust in Galactic Halos on Emission Line Ratios
• The Shocking Properties of Supersonic Flows: Dependence of the Thermal Overstability on M, alpha, and T_c/T_0
• The Ultraviolet flash accompanying GRBs from neutron-rich internal shocks
• Constraints on Stirring and Dissipation of MHD Turbulence in Molecular Clouds
• Fragmentation and Structure Formation

Cited by in corpus (26)

• Molecular Cloud Evolution II. From cloud formation to the early stages of star formation in decaying conditions
• Global Hierarchical Collapse In Molecular Clouds. Towards a Comprehensive Scenario
• Dynamic star formation in the massive DR21 filament
• Accretion-Driven Turbulence as Universal Process: Galaxies, Molecular Clouds, and Protostellar Disks
• The Virial Balance of Clumps and Cores in Molecular Clouds
• Efficiently Cooled Stellar Wind Bubbles in Turbulent Clouds I. Fractal Theory and Application to Star-Forming Clouds
• Evolution of supernovae-driven superbubbles with conduction and cooling
• On the structure of the turbulent interstellar atomic hydrogen. I- Physical characteristics
• The Nature of the Velocity Field in Molecular Clouds. I. The Non-Magnetic Case
• An Evolutionary Model for Collapsing Molecular Clouds and Their Star Formation Activity
• On the Structure of the Turbulent Interstellar Clouds
• Magnetic fields in massive stars, their winds, and their nebulae
• Formation and Collapse of Quiescent Cloud Cores Induced by Dynamic Compressions
• Numerical heat conduction in hydrodynamical models of colliding hypersonic flows
• Circum-stellar medium around rotating massive stars at solar metallicity
• Simulations of the non-linear thin shell instability
• Spectroscopy of SMC Wolf-Rayet Stars Suggests that Wind-Clumping does not Depend on Ambient Metallicity
• Supersonic turbulence in 3D isothermal flow collision
• Ambient magnetic field amplification in shock fronts of relativistic jets: an application to GRB afterglows
• A well-balanced scheme for the simulation tool-kit A-MaZe: implementation, tests, and first applications to stellar structure
• The Eastern Filament of W50
• Cooling and Instabilities in Colliding Flows
• The interplay of the collisionless nonlinear thin-shell instability with the ion acoustic instability
• Recurrent Novae: Progenitors of SN Ia?
• Supersonically Turbulent, Shock Bound Interaction Zones
• Effects of radiative losses on the relativistic jets of high-mass microquasars