Shock tube

About: Shock tube is a research topic. Over the lifetime, 6963 publications have been published within this topic receiving 99372 citations.

Physics of shock waves in gases and plasmas

Abstract: 1. Introduction to the Theory of Gasdynamic Shock Waves.- 1.1 Equations of Motion.- 1.1.1 Conservation Laws and the Euler Equation.- 1.1.2 Viscosity and Heat Transfer in a Fluid. The Navier-Stokes Equation.- 1.2 Kinetic Theory and Gasdynamic Equations.- 1.2.1 Kinetic Equations for a Gas.- 1.2.2 Obtaining the Gasdynamic Equations.- 1.3 Limits of Applicability of the Gasdynamic Equations in Studying Shock-Wave Structure.- 1.4 Linear and Nonlinear Waves.- 1.4.1 Linear and Sonic Waves.- 1.4.2 Nonlinear Plane Waves.- 1.4.3 The Riemann Invariants.- 1.4.4 Simple Waves.- 1.4.5 Expansion Waves.- 1.5 Origins of Discontinuities.- 1.5.1 Profile Distortion of a Running Wave.- 1.5.2 Breakdown of the Sonic Wave Front.- 1.5.3 Burgers' Equation. Evolution of Spectral Composition of the Sonic Wave.- 1.6 Discontinuities and Shocks.- 1.6.1 Discontinuous Solutions.- 1.6.2 The Solution of Burgers' Equation for the Profile of a Weak Shock Wave.- 1.6.3 The Shock Adiabat.- 1.6.4 Production of Shock Waves. Elementary Theory of a Shock Tube.- 1.7 Criteria of Stability and Evolutionarity of Discontinuities.- 1.7.1 Evolutionarity.- 1.7.2 Evolutionarily Condition and Existence of the Shock Structure. Basic and Additional Relations on the Front.- 1.7.3 Spectra of Dissipative Waves, Corresponding to Shock-Wave Structure Described by Burgers' Equation for the Profile of a Weak Shock Wave.- 1.6.3 The Shock Adiabat.- 1.6.4 Production of Shock Waves. Elementary Theory of a Shock Tube.- 1.7 Criteria of Stability and Evolutionarity of Discontinuities.- 1.7.1 Evolutionarity.- 1.7.2 Evolutionarily Condition and Existence of the Shock Structure. Basic and Additional Relations on the Front.- 1.7.3 Spectra of Dissipative Waves, Corresponding to Shock-Wave Structure Described by Burgers' Equation.- 1.7.4 Stability and Evolutionarity of Plane Discontinuities in Three Dimensions.- 1.8 Structures of Gasdynamic Shock Waves.- 1.8.1 Equations of the Shock Layer.- 1.8.2 Shock Structure Shaped by Viscosity Alone.- 1.8.3 Shock-Front Structure in a Gas with High Heat Conductivity.- 1.9 Detonation and Deflagration.- 1.9.1 Propagation of an Exothermal Reaction. Equations of Structure of the Reaction Zone.- 1.9.2 Structures of the Detonation and Deflagration Fronts.- 1.9.3 Realization of Different Propagation Regimes of the Reaction. The Piston Problem.- 2. Gas Shock Ionization and Shock-Wave Structures in Plasmas.- 2.1 Shock Structures in a Completely Ionized Plasma.- 2.1.1 Equations for the Shock Layer and Boundary Conditions.- 2.1.2 Structure of a Weak Shock Wave.- 2.1.3 Structure of a Strong Shock Wave.- 2.1.4 Polarization of Plasma in Shock Waves.- 2.2 Shock Structure in a Plasma with Ionization.- 2.2.1 Shock-Layer Equations and Boundary Conditions.- 2.2.2 Shock Structure Associated with Multiple Ionization.- 2.2.3 Shock Structure in Partially Ionized Argon.- 2.3 Structure of an Ionizing Shock Wave.- 2.3.1 Morphology.- 2.3.2 Structure of the Precursor Region.- 2.3.3 Precursor Ionization in Electromagnetic Shock Tubes.- 2.3.4 Structure of the Ionization-Relaxation and Radiative Cooling Regions.- 2.4 Effects of Plasma Flow Nonunidimensionality in Ionizing Shock Waves.- 2.4.1 Effects of the Wall Boundary Layer in a Shock Tube on the Structure of the Relaxation Region.- 2.4.2 Instability of Ionizing Shock Waves.- 3. Magnetohydrodynamic Shock Waves in Plasmas.- 3.1 Basic Equations.- 3.1.1 Magnetohydrodynamic Equations.- 3.1.2 Two-Fluid Transfer Equations for a Plasma.- 3.2 Magnetohydrodynamic Waves.- 3.2.1 Linear MHD Waves.- 3.2.2 Damping and Dispersion of Linear MHD Waves.- 3.2.3 Nonlinear Simple MHD Waves.- 3.3 Discontinuities and Shock Waves in Magnetohydrodynamics.- 3.3.1 Classification of Discontinuities.- 3.3.2 Boundary Conditions and the Shock Adiabat in Magnetohydrodynamics.- 3.3.3 Evolutionarity Conditions for MHD Shock Waves.- 3.3.4 Shock Structures in the MHD Approximation.- 3.3.5 Evolutionarity of Singular MHD Shock Waves.- 3.4 Structures of Transverse Shocks.- 3.4.1 Boundary Conditions and the Shock Adiabat.- 3.4.2 Structure of Transverse Shock Waves in Magnetized Plasmas.- 3.4.3 Structures of Transverse Shock Waves in Nonmagnetized and Partly Magnetized Plasmas.- 3.4.4 Plasma Polarization in Transverse Shock Waves.- 3.4.5 Experimental Investigations of Transverse Shock Waves in Plasma.- 3.5 Structures of Switch-On Shock Waves.- 3.5.1 Boundary Conditions and the Shock Adiabat.- 3.5.2 Switch-On Shock-Wave Structures in Nonmagnetized Plasma.- 3.5.3 Switch-On Shock-Wave Structure in Magnetized Plasma.- 3.6 Structures of Switch-Off Shock Waves.- 4. Ionizing Shock Waves in Magnetic Fields: Structures and Stability.- 4.1 Classification and the Problem of Boundary Conditions.- 4.1.1 The Basic Boundary Conditions.- 4.1.2 Evolutionarity Conditions.- 4.2 Shock Structures and Additional Boundary Conditions.- 4.2.1 Magnetic Structures of Ionizing Shocks as Pm? 0.- 4.2.2 The Criterion for Distinguishing Between Ionizing and MHD Shock Propagation Regimes.- 4.2.3 Precursor Ionization in a Magnetic Field. Conditions for the Ionization Stability of the Upstream Flow.- 4.2.4 Additional Boundary Conditions and the Magnetic Structures of Ionizing Shocks.- 4.2.5 Limiting Regimes.- 4.3 Transverse Ionizing Shock Waves.- 4.3.1 Magnetic Structures.- 4.3.2 Additional Boundary Conditions and Structures of Transverse Ionizing Shocks.- 4.3.3 Structure of Transverse MHD Shocks in Partially Ionized Plasma.- 4.4 Normal Ionizing Shock Waves.- 4.4.1 Magnetic Structures.- 4.4.2 Tensor Conductivity and Joule Heating of Plasmas in Normal Ionizing Shocks.- 4.4.3 Switch-On MHD Shocks in Partially Ionized Plasmas.- 4.5 Switch-Off Ionizing Shock Waves.- 5. Dynamics of Shock Waves in Magnetic Fields.- 5.1 Electromagnetic Shock Tubes.- 5.1.1 Design and Operation of Electromagnetic Shock Tubes.- 5.1.2 Elementary Theory of Electromagnetic Shock Tubes: The Snowplow Model.- 5.1.3 Effects of Nonunidimensionality of the Plasma Flow in Coaxial Electromagnetic Shock Tubes.- 5.2 Piston Problem.- 5.2.1 Self-Similar Magnetic Piston Problem in Magnetohydrodynamics.- 5.2.2 Self-Similar Piston Problem for Flows with Ionizing Shock Waves.- 5.3 Dynamics of Transverse Shocks in Magnetized Plasma.- 5.4 Evolution of the Initial Ionizing Discontinuity in the Transverse Magnetic Field.- 5.5 Shaping the Structure of the Normal Ionizing Shock.- References.

Thermoacoustic effects in a resonance tube

Abstract: New experiments with a gas-filled resonance tube have shown that not only heating, but also cooling of the tube wall is possible and that these phenomena are not restricted to oscillation amplitudes that generate shocks. The present paper concentrates on amplitudes outside the shock region. For this case, an extended acoustic theory is worked out. The results show cooling in the section of the tube with maximum velocity amplitude (and thus dissipation) and marked heating in the region of the velocity nodes. A strong dependence of these effects on the Prandtl number is noted. The results are in good agreement with experiments. Although the theory is not valid for proper resonance conditions, it nevertheless sheds some light on what happens when nonlinear effects dominate.Closely related to the limit of validity of the thermoacoustic theory is the question of transition from laminar to turbulent flow in the viscous boundary layer (Stokes layer). This problem has also been investigated; the results are given in a separate paper (Merkli & Thomann 1975). In the present article laminar flow is assumed.

Quasi‐One‐Dimensional, Nonequilibrium Gas Dynamics of Partially Ionized Two‐Temperature Argon

Abstract: A set of equations governing the quasi‐one‐dimensional flow of a nonequilibrium argon plasma is formulated. The kinetic model includes ionization by atom‐atom and electron‐atom impacts, together with the three‐body recombination counterparts of these processes. The electron gas temperature—a key variable in controlling ionization reaction rates in a noble gas—is not necessarily equal to that of the heavy particles and must in general be found by simultaneous solution of a differential electron energy equation together with the usual conservation equations. Numerical solutions are obtained for the special case of the relaxation zone behind strong normal shocks which give good agreement with shock tube measured ionization times. For these normal‐shock calculations, a local steady‐state approximation to the electron energy equation is found to be useful in view of an insensitivity, demonstrated by the numerical results, to arbitrarily selected initial values of post‐translational shock electron temperature.

Simulating cosmic ray physics on a moving mesh

Abstract: We discuss new methods to integrate the cosmic ray (CR) evolution equations coupled to magneto-hydrodynamics (MHD) on an unstructured moving mesh, as realised in the massively parallel AREPO code for cosmological simulations. We account for diffusive shock acceleration of CRs at resolved shocks and at supernova remnants in the interstellar medium (ISM), and follow the advective CR transport within the magnetised plasma, as well as anisotropic diffusive transport of CRs along the local magnetic field. CR losses are included in terms of Coulomb and hadronic interactions with the thermal plasma. We demonstrate the accuracy of our formalism for CR acceleration at shocks through simulations of plane-parallel shock tubes that are compared to newly derived exact solutions of the Riemann shock tube problem with CR acceleration. We find that the increased compressibility of the post-shock plasma due to the produced CRs decreases the shock speed. However, CR acceleration at spherically expanding blast waves does not significantly break the self-similarity of the Sedov-Taylor solution; the resulting modifications can be approximated by a suitably adjusted, but constant adiabatic index. In first applications of the new CR formalism to simulations of isolated galaxies and cosmic structure formation, we find that CRs add an important pressure component to the ISM that increases the vertical scale height of disk galaxies, and thus reduces the star formation rate. Strong external structure formation shocks inject CRs into the gas, but the relative pressure of this component decreases towards halo centres as adiabatic compression favours the thermal over the CR pressure.