Shock wave

About: Shock wave is a research topic. Over the lifetime, 36184 publications have been published within this topic receiving 635848 citations. The topic is also known as: Shock waves & shockwave.

Bubble dynamics, shock waves and sonoluminescence

Abstract: Sound and light emission by bubbles is studied experimentally. Single bubbles kept in a bubble trap and single lasergenerated bubbles are investigated using ultrafast and highspeed photography in c...

Applied Gas Dynamics

Abstract: Preface. About the Author. 1 Basic Facts. 1.1 Definition of Gas Dynamics. 1.2 Introduction. 1.3 Compressibility. 1.4 Supersonic Flow What is it? 1.5 Speed of Sound. 1.6 Temperature Rise. 1.7 Mach Angle. 1.8 Thermodynamics of Fluid Flow. 1.9 First Law of Thermodynamics (Energy Equation). 1.10 The Second Law of Thermodynamics (Entropy Equation). 1.11 Thermal and Calorical Properties. 1.12 The Perfect Gas. 1.13 Wave Propagation. 1.14 Velocity of Sound. 1.15 Subsonic and Supersonic Flows. 1.16 Similarity Parameters. 1.17 Continuum Hypothesis. 1.18 Compressible Flow Regimes. 1.19 Summary. Exercise Problems. 2 Steady One-Dimensional Flow. 2.1 Introduction. 2.2 Fundamental Equations. 2.3 Discharge from a Reservoir. 2.4 Streamtube Area Velocity Relation. 2.5 de Laval Nozzle. 2.6 Supersonic Flow Generation. 2.7 Performance of Actual Nozzles. 2.8 Diffusers. 2.9 Dynamic Head Measurement in Compressible Flow. 2.10 Pressure Coefficient. 2.11 Summary. Exercise Problems. 3 Normal Shock Waves. 3.1 Introduction. 3.2 Equations of Motion for a Normal Shock Wave. 3.3 The Normal Shock Relations for a Perfect Gas. 3.4 Change of Stagnation or Total Pressure Across a Shock. 3.5 Hugoniot Equation. 3.6 The Propagating Shock Wave. 3.7 Reflected Shock Wave. 3.8 Centered Expansion Wave. 3.9 Shock Tube. 3.10 Summary. Exercise Problems. 4 Oblique Shock and ExpansionWaves. 4.1 Introduction. 4.2 Oblique Shock Relations. 4.3 Relation between and . 4.4 Shock Polar. 4.5 Supersonic Flow Over a Wedge. 4.6 Weak Oblique Shocks. 4.7 Supersonic Compression. 4.8 Supersonic Expansion by Turning. 4.9 The Prandtl Meyer Expansion. 4.10 Simple and Nonsimple Regions. 4.11 Reflection and Intersection of Shocks and Expansion Waves. 4.12 Detached Shocks. 4.13 Mach Reflection. 4.14 Shock-Expansion Theory. 4.15 Thin Aerofoil Theory. 4.15.1 Application of Thin Aerofoil Theory. 4.16 Summary. Exercise Problems. 5 Compressible Flow Equations. 5.1 Introduction. 5.2 Crocco's Theorem. 5.3 General Potential Equation for Three-Dimensional Flow. 5.4 Linearization of the Potential Equation. 5.5 Potential Equation for Bodies of Revolution. 5.6 Boundary Conditions. 5.7 Pressure Coefficient. 5.8 Summary. Exercise Problems. 6 Similarity Rule. 6.1 Introduction. 6.2 Two-Dimensional Flow: The Prandtl-Glauert Rule for Subsonic Flow. 6.3 Prandtl Glauert Rule for Supersonic Flow: Versions I and II. 6.4 The von Karman Rule for Transonic Flow. 6.5 Hypersonic Similarity. 6.6 Three-Dimensional Flow: Gothert s Rule. 6.7 Summary. Exercise Problems. 7 Two-Dimensional Compressible Flows. 7.1 Introduction. 7.2 General Linear Solution for Supersonic Flow. 7.3 Flow Over a Wave-Shaped Wall. 7.4 Summary. Exercise Problems. 8 Flow with Friction and Heat Transfer. 8.1 Introduction. 8.2 Flow in Constant Area Duct with Friction. 8.4 Flow with Heating or Cooling in Ducts. 8.5 Summary. Exercise Problems. 9 Method of Characteristics. 9.1 Introduction. 9.2 The Concepts of Characteristic. 9.3 The Compatibility Relation. 9.4 The Numerical Computational Method. 9.5 Theorems for Two-Dimensional Flow. 9.6 Numerical Computation with Weak Finite Waves. 9.7 Design of Supersonic Nozzle. 9.8 Summary. 10 Measurements in Compressible Flow. 10.1 Introduction. 10.2 Pressure Measurements. 10.3 Temperature Measurements. 10.4 Velocity and Direction. 10.5 Density Problems. 10.6 Compressible Flow Visualization. 10.7 Interferometer. 10.8 Schlieren System. 10.9 Shadowgraph. 10.10 Wind Tunnels. 10.11 Hypersonic Tunnels. 10.12 Instrumentation and Calibration of Wind Tunnels. 10.13 Calibration and Use of Hypersonic Tunnels. 10.14 Flow Visualization. 10.15 Summary. Exercise Problems. 11 Ramjet. 11.1 Introduction. 11.2 The Ideal Ramjet. 11.3 Aerodynamic Losses. 11.4 Aerothermodynamics of Engine Components. 11.5 Flow Through Inlets. 11.6 Performance of Actual Intakes. 11.7 Shock Boundary Layer Interaction. 11.8 Oblique Shock Wave Incident on Flat Plate. 11.9 Normal Shocks in Ducts. 11.10 External Supersonic Compression. 11.11 Two-Shock Intakes. 11.12 Multi-Shock Intakes. 11.13 Isentropic Compression. 11.14 Limits of External Compression. 11.15 External Shock Attachment. 11.16 Internal Shock Attachment. 11.17 Pressure Loss. 11.18 Supersonic Combustion. 11.19 Summary. 12 Jets. 12.1 Introduction. 12.2 Mathematical Treatment of Jet Profiles. 12.3 Theory of Turbulent Jets. 12.4 Experimental Methods for Studying Jets and the Techniques Used for Analysis. 12.5 Expansion Levels of Jets. 12.6 Control of Jets. 12.7 Summary. Appendix. References. Index.

Direct Observation of the alpha-epsilon Transition in Shock-compressed Iron via Nanosecond X-ray Diffraction

Abstract: In-situ x-ray diffraction studies of iron under shock conditions confirm unambiguously a phase change from the bcc ({alpha}) to hcp ({var_epsilon}) structure. Previous identification of this transition in shock-loaded iron has been inferred from the correlation between shock wave-profile analyses and static high-pressure x-ray measurements. This correlation is intrinsically limited because dynamic loading can markedly affect the structural modifications of solids. The in-situ measurements are consistent with a uniaxial collapse along the [001] direction and shuffling of alternate (110) planes of atoms, and in good agreement with large-scale non-equilibrium molecular dynamics simulations.

Coupled Hydromagnetic Wave Excitation and Ion Acceleration at an Evolving Coronal/Interplanetary Shock

Abstract: An analytical quasilinear theory is presented for the evolution of a "gradual" event consisting of solar energetic particles (SEPs) accelerated at an evolving coronal/interplanetary shock. The upstream ion transport is described by the two-stream moments of the focused transport equation, which accommodate the large streaming anisotropies observed near event onset. The proton transport equations and a wave kinetic equation are solved together for the coupled behavior of the hydromagnetic waves and the energetic protons. The theory includes diffusive shock acceleration, ion advection with the solar wind, spatial diffusion upstream of the shock, magnetic focusing, wave excitation by the energetic protons, and minor ions as test particles. A number of approximations are made for analytical tractability. The predictions reproduce the observed phases of most gradual SEP events: onset, a "plateau" with large streaming anisotropy, an "energetic storm particle" (ESP) enhancement prior to shock passage, and the decaying "invariant spectra" after shock passage. The theory treats naturally the transition from a scatter-dominated sheath adjacent to the shock where the wave intensity is enhanced to the nearly scatter-free ion transport in interplanetary space. The plateau is formed by ions that are extracted from the outer edge of the scatter-dominated sheath by magnetic focusing and escape into interplanetary space; it corresponds quantitatively to the "streaming limit" identified and interpreted in gradual events by D. V. Reames and C. K. Ng. The ion energy spectra at the shock have the standard power-law form dependent on shock strength, which is expected for diffusive shock acceleration, with a high-energy cutoff whose form is determined self-consistently by the ion escape rate. The increased shock strength, magnetic field magnitude, and injection energies close to the Sun account for the observed predominance of high-energy ions early in the event. The downstream ion transport is determined under two extreme assumptions: (i) vanishing diffusive transport and (ii) effective diffusive transport leading to small ion spatial gradients. The latter assumption reproduces the invariant spectra, spatial gradients, and exponential temporal decay observed in the late phase of many events. The minor ion distributions exhibit fractionation due to rigidity-dependent transport and acceleration. However, their energy spectra, spatial gradients, and high-energy cutoffs do not reproduce observed forms and lead to excessive fractionation. The origin of these discrepancies is probably the neglect of nonlinear processes. Although not easily incorporated in the theory, these processes could substantially modify the predicted wave intensity. An illustrative calculation assuming an arbitrary power-law form for the wave intensity demonstrates the sensitive dependence of ion fractionation on the power-law index.