The Experts below are selected from a list of 24723 Experts worldwide ranked by ideXlab platform
Riccardo Bonazza - One of the best experts on this subject based on the ideXlab platform.
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experimental validation of a richtmyer meshkov scaling law over large density ratio and Shock Strength ranges
Physics of Fluids, 2009Co-Authors: Bradley Motl, Jason Oakley, Devesh Ranjan, C R Weber, Mark H Anderson, Riccardo BonazzaAbstract:A universal scaling law for the Richtmyer–Meshkov instability is validated with experimental results covering a wide range of density ratios and Shock Strengths. These results include the first membraneless, gas-phase, interface experiments for A>0.5 and M>1.5. The Shock-accelerated, sinusoidal interface experiments are conducted in a vertical Shock tube with a large square cross section and cover the experimental parameter space: 0.29
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experimental validation of a richtmyer meshkov scaling law over large density ratio and Shock Strength ranges
Physics of Fluids, 2009Co-Authors: Bradley Motl, Jason Oakley, Devesh Ranjan, C R Weber, Mark H Anderson, Riccardo BonazzaAbstract:A universal scaling law for the Richtmyer–Meshkov instability is validated with experimental results covering a wide range of density ratios and Shock Strengths. These results include the first membraneless, gas-phase, interface experiments for A>0.5 and M>1.5. The Shock-accelerated, sinusoidal interface experiments are conducted in a vertical Shock tube with a large square cross section and cover the experimental parameter space: 0.29
Guangcai Zhang - One of the best experts on this subject based on the ideXlab platform.
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polar coordinate lattice boltzmann kinetic modeling of detonation phenomena
Communications in Theoretical Physics, 2014Co-Authors: Guangcai Zhang, Aiguo Xu, Yingjun LiAbstract:A novel polar coordinate lattice Boltzmann kinetic model for detonation phenomena is presented and applied to investigate typical implosion and explosion processes. In this model, the change of discrete distribution function due to local chemical reaction is dynamically coupled into the modified lattice Boltzmann equation which could recover the Navier Stokes equations, including contribution of chemical reaction, via the Chapman-Enskog expansion. For the numerical investigations, the main focuses are the none quilibrium behaviors in these processes. The system at the disc center is always in its thermodynamic equilibrium in the highly symmetric case. The internal kinetic energies in different degrees of freedom around the detonation front do not coincide. The dependence of the reaction rate on the pressure, influences of the Shock Strength and reaction rate on the departure amplitude of the system from its local thermodynamic equilibrium are probed.
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polar coordinate lattice boltzmann kinetic modeling of detonation phenomena
arXiv: Soft Condensed Matter, 2013Co-Authors: Chuandong Lin, Guangcai ZhangAbstract:A novel polar coordinate lattice Boltzmann kinetic model for detonation phenomena is presented and applied to investigate typical implosion and explosion processes. In this model, the change of discrete distribution function due to local chemical reaction is dynamically coupled into in the modified lattice Boltzmann equation, which could recovery the Navier-Stokes equations, including contribution of chemical reaction, via the Chapman-Enskog expansion. For the numerical investigations, the main focuses are the nonequilibrium behaviors in these processes. The system at the disc center is always in its thermodynamic equilibrium. The internal kinetic energies in different degrees freedoms around the detonation front do not coincide due to the fluid viscosity. They show the maximum difference at the inflexion point where the pressure has the largest spatial derivative. The dependence of the reaction rate on the pressure, influences of the Shock Strength and reaction rate on the departure amplitude of the system from its local thermodynamic equilibrium are probed.
P. K. Sahu - One of the best experts on this subject based on the ideXlab platform.
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Cylindrical Shock waves in rotational axisymmetric non-ideal dusty gas with increasing energy under the action of monochromatic radiation
Physics of Fluids, 2017Co-Authors: P. K. SahuAbstract:The propagation of a cylindrical Shock wave in a rotational axisymmetric non-ideal dusty gas under the action of monochromatic radiation with increasing energy, which has variable azimuthal and axial components of fluid velocity, is investigated. The dusty gas is assumed to be a mixture of non-ideal (or perfect) gas and small solid particles, in which solid particles are continuously distributed. Similarity solutions are obtained as well as the effects of the variation of the radiation parameters, the parameter of non-idealness of the gas, the mass concentration of solid particles in the mixture, the ratio of the density of solid particles to the initial density of the gas, and the piston velocity index are worked out in detail. The total energy of the Shock wave is varying and increases with time. It is observed that the radiation parameter and the piston velocity index have opposite behaviour on the flow variables as well as the Shock Strength.
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propagation of a cylindrical Shock wave in a mixture of a non ideal gas and small solid particles under the action of monochromatic radiation
Combustion Explosion and Shock Waves, 2017Co-Authors: G. Nath, P. K. SahuAbstract:A cylindrical Shock wave in a dusty gas under the action of monochromatic radiation into the stellar atmosphere with a constant intensity per unit area is discussed. The gas is assumed to be grey and opaque, and the Shock is assumed to be transparent. The dusty gas is considered as a mixture of a non-ideal gas and small solid particles. To obtain some essential features of Shock propagation, small solid particles are considered as a pseudo-fluid, and it is assumed that the equilibrium flow condition is maintained in the entire flowfield. The effects of the parameters of the gas non-idealness, the mass concentration of solid particles in the mixture, the ratio of the density of solid particles to the initial density of the gas, and the radiation parameter on flow variables are investigated. It is shown that an increase in the gas non-idealness and the radiation parameter has a decaying effect on the Shock waves, whereas the Shock Strength increases with an increase in the ratio of the density of solid particles to the initial density of the gas. It is found that an increase in the gas non-idealness and the ratio of the density of solid particles to the initial density of the gas has the opposite effects on the fluid velocity, pressure, and Shock Strength. It is also shown that an increase in the radiation parameter has a trend to decrease the flow variables and the Shock Strength.
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self similar solution of a cylindrical Shock wave under the action of monochromatic radiation in a rotational axisymmetric dusty gas
Communications in Theoretical Physics, 2017Co-Authors: G. Nath, P. K. SahuAbstract:A self-similar flow behind a cylindrical Shock wave is studied under the action of monochromatic radiation in a rotational axisymmetric dusty gas. The dusty gas is taken to be a mixture of small solid particles and perfect gas, and solid particles are continuously distributed in the mixture. The similarity solutions are obtained and the effects of the variation of the radiation parameter, the ratio of the density of solid particles to the initial density of the gas, the mass concentration of solid particles in the mixture and the index for the time dependent energy law are investigated. It is observed that an increase in the radiation parameter has decaying effect on the Shock waves; whereas the Shock Strength increases with an increase in the ratio of the density of solid particles to the initial density of the gas or the index for the time dependent energy law. Also, it is found that an increase in the radiation parameter has effect to decrease the flow variables except the density and the azimuthal component of fluid velocity. A comparison is also made between rotating and non-rotating cases.
Bradley Motl - One of the best experts on this subject based on the ideXlab platform.
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experimental validation of a richtmyer meshkov scaling law over large density ratio and Shock Strength ranges
Physics of Fluids, 2009Co-Authors: Bradley Motl, Jason Oakley, Devesh Ranjan, C R Weber, Mark H Anderson, Riccardo BonazzaAbstract:A universal scaling law for the Richtmyer–Meshkov instability is validated with experimental results covering a wide range of density ratios and Shock Strengths. These results include the first membraneless, gas-phase, interface experiments for A>0.5 and M>1.5. The Shock-accelerated, sinusoidal interface experiments are conducted in a vertical Shock tube with a large square cross section and cover the experimental parameter space: 0.29
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experimental validation of a richtmyer meshkov scaling law over large density ratio and Shock Strength ranges
Physics of Fluids, 2009Co-Authors: Bradley Motl, Jason Oakley, Devesh Ranjan, C R Weber, Mark H Anderson, Riccardo BonazzaAbstract:A universal scaling law for the Richtmyer–Meshkov instability is validated with experimental results covering a wide range of density ratios and Shock Strengths. These results include the first membraneless, gas-phase, interface experiments for A>0.5 and M>1.5. The Shock-accelerated, sinusoidal interface experiments are conducted in a vertical Shock tube with a large square cross section and cover the experimental parameter space: 0.29
Sanjiva K Lele - One of the best experts on this subject based on the ideXlab platform.
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direct numerical simulation of canonical Shock turbulence interaction
Physics of Fluids, 2009Co-Authors: Johan Larsson, Sanjiva K LeleAbstract:A set of direct numerical simulations of isotropic turbulence passing through a nominally normal Shock wave is presented. Upstream of the Shock, the microscale Reynolds number is 40, the mean Mach number is 1.3–6.0, and the turbulence Mach number is 0.16–0.38. It is shown that the Kolmogorov scale decreases during the Shock interaction, which implies that the grid resolution needed to resolve the viscous dissipation is finer than that used in previous studies. This leads to some qualitative differences with previous work, e.g., a rapid increase in the streamwise vorticity variance behind the Shock and large anisotropy of the postShock Reynolds stresses. The instantaneous structure of the Shock/turbulence interaction is examined using averages conditioned on the instantaneous Shock Strength. For locally strong compressions, the flow is characterized by overcompression, followed by an expansion. At points where the Shock is locally weak, the profiles differ qualitatively depending on the Strength of the inc...
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interaction of isotropic turbulence with Shock waves effect of Shock Strength
Journal of Fluid Mechanics, 1997Co-Authors: Sangsan Lee, Sanjiva K Lele, Parviz MoinAbstract:As an extension of the authors' work on isotropic vortical turbulence interacting with a Shock wave (Lee, Lele & Moin 1993), direct numerical simulation and linear analysis are performed for stronger Shock waves to investigate the effects of the upstream Shock-normal Mach number (M 1 ). A Shock-capturing scheme is developed to accurately simulate the unsteady interaction of turbulence with Shock waves. Turbulence kinetic energy is amplified across the Shock wave, and this amplification tends to saturate beyond M 1 = 3.0. An existing controversy between experiments and theoretical predictions on length scale change is thoroughly investigated through the Shock-capturing simulation: most turbulence length scales decrease across the Shock, while the dissipation length scale ( ρ q 3 /e) increases slightly for Shock waves with M 1 <1.65. Fluctuations in thermodynamic variables behind the Shock wave are nearly isentropic for M 1 <1.2, and deviate significantly from isentropy for the stronger Shock waves, due to the entropy fluctuation generated through the interaction.
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direct numerical simulation of isotropic turbulence interacting with a weak Shock wave
Journal of Fluid Mechanics, 1993Co-Authors: Sangsan Lee, Sanjiva K Lele, Parviz MoinAbstract:Interaction of isotropic quasi-incompressible turbulence with a weak Shock wave was studied by direct numerical simulations. The effects of the fluctuation Mach number Mt of the upstream turbulence and the Shock Strength M21 — 1 on the turbulence statistics were investigated. The ranges investigated were 0.0567 ≤ Mt ≤ 0.110 and 1.05 ≤ M1 ≤ 1.20. A linear analysis of the interaction of isotropic turbulence with a normal Shock wave was adopted for comparisons with the simulations.Both numerical simulations and the linear analysis of the interaction show that turbulence is enhanced during the interaction with a Shock wave. Turbulent kinetic energy and transverse vorticity components are amplified, and turbulent lengthscales are decreased. The predictions of the linear analysis compare favourably with simulation results for flows with M2t a(M21— 1 with a ≈ 0.1, Shock waves no longer had well-defined fronts: Shock wave thickness and Strength varied widely along the transverse directions. Multiple compression peaks were found along the mean streamlines at locations where the local Shock thickness had increased significantly.