Shock Wave—Turbulence Interactions

Andreopoulos, Yiannis; Agui, Juan H.; Briassulis, G.

doi:10.1146/annurev.fluid.32.1.309

Cited by 244 publications

(130 citation statements)

References 81 publications

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“…The moving shock wave over the aerofoil surface exhibits substantial unsteadiness and deformation as a result of the interaction, whereas the turbulent quantities change considerably (Andreopoulos et al 2000). Thus, another objective of this study is to investigate turbulent boundary layer characteristics.…”

Section: Turbulent Boundary Layer Characteristics 421 Division Of mentioning

confidence: 99%

Numerical investigation of the compressible flow past an aerofoil

Chen

2009

J. Fluid Mech.

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Numerical investigation of the compressible flow past an 18% thick circular-arc aerofoil was carried out using detached-eddy simulation for a free-stream Mach number M∞ = 0.76 and a Reynolds number Re = 1.1 × 107. Results have been validated carefully against experimental data. Various fundamental mechanisms dictating the intricate flow phenomena, including moving shock wave behaviours, turbulent boundary layer characteristics, kinematics of coherent structures and dynamical processes in flow evolution, have been studied systematically. A feedback model is developed to predict the self-sustained shock wave motions repeated alternately along the upper and lower surfaces of the aerofoil, which is a key issue associated with the complex flow phenomena. Based on the moving shock wave characteristics, three typical flow regimes are classified as attached boundary layer, moving shock wave/turbulent boundary layer interaction and intermittent boundary layer separation. The turbulent statistical quantities have been analysed in detail, and different behaviours are found in the three flow regimes. Some quantities, e.g. pressure-dilatation correlation and dilatational dissipation, have exhibited that the compressibility effect is enhanced because of the shock wave/boundary layer interaction. Further, the kinematics of coherent vortical structures and the dynamical processes in flow evolution are analysed. The speed of downstream-propagating pressure waves in the separated boundary layer is consistent with the convection speed of the coherent vortical structures. The multi-layer structures of the separated shear layer and the moving shock wave are reasonably captured using the instantaneous Lamb vector divergence and curl, and the underlying dynamical processes are clarified. In addition, the proper orthogonal decomposition analysis of the fluctuating pressure field illustrates that the dominated modes are associated with the moving shock waves and the separated shear layers in the trailing-edge region. The results obtained in this study provide physical insight into the understanding of the mechanisms relevant to this complex flow.

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Section: Turbulent Boundary Layer Characteristics 421 Division Of mentioning

confidence: 99%

Numerical investigation of the compressible flow past an aerofoil

Chen

2009

J. Fluid Mech.

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“…RMI-like flows appear, for example, in astrophysics (Andreopoulos et al 2000) and in the shock remnants following a supernova explosion. It is also an important phenomenon in inertial confinement fusion (ICF), as it invariably develops during the early stages of target irradiation, when a sequence of shocks travels through the target.…”

Section: Introductionmentioning

confidence: 99%

Richtmyer–Meshkov instability: theory of linear and nonlinear evolution

Nishihara

Wouchuk

Matsuoka

et al. 2010

Phil. Trans. R. Soc. A.

129

128

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A theoretical framework to study linear and nonlinear Richtmyer-Meshkov instability (RMI) is presented. This instability typically develops when an incident shock crosses a corrugated material interface separating two fluids with different thermodynamic properties. Because the contact surface is rippled, the transmitted and reflected wavefronts are also corrugated, and some circulation is generated at the material boundary. The velocity circulation is progressively modified by the sound wave field radiated by the wavefronts, and ripple growth at the contact surface reaches a constant asymptotic normal velocity when the shocks/rarefactions are distant enough. The instability growth is driven by two effects: an initial deposition of velocity circulation at the material interface by the corrugated shock fronts and its subsequent variation in time due to the sonic field of pressure perturbations radiated by the deformed shocks. First, an exact analytical model to determine the asymptotic linear growth rate is presented and its dependence on the governing parameters is briefly discussed. Instabilities referred to as RM-like, driven by localized non-uniform vorticity, also exist; they are either initially deposited or supplied by external sources. Ablative RMI and its stabilization mechanisms are discussed as an example. When the ripple amplitude increases and becomes comparable to the perturbation wavelength, the instability enters the nonlinear phase and the perturbation velocity starts to decrease. An analytical model to describe this second stage of instability evolution is presented within the limit of incompressible and irrotational fluids, based on the dynamics of the contact surface circulation. RMI in solids and liquids is also presented via molecular dynamics simulations for planar and cylindrical geometries, where we show the generation of vorticity even in viscid materials.

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“…Acoustic and entropic modes in a jet are studied by analyzing density fluctuations inside and outside the flow [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

Optimization of Parametric Periodograms for the Study of Density Fluctuations in a Supersonic Jet

Forgach¹,

Reyes²

2013

JSIP

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In our research on the density fluctuations of a supersonic jet we were confronted with a quite difficult problem. In the power spectrum obtained either with a spectrum analyzer, the peaks of the two of the modes that we wanted to identify overlapped. We needed to find a signal processing method that would resolve the two main frequencies. We made a thorough investigation of several methods and thought that parametric periodograms were the appropriate tool. The use of parametric periodograms in signal processing requires constant training. The proper application of this tool depends on the determination of the number of parameters that has to be used to best model a real signal. The methods generally used to determine this number are subjective, depending on trial and error and on the experience of the user. Some of these methods rely on the minimization of the estimated variance of the linear prediction error , as a function of the number of parameters n. In many cases, the graph vs n doesn't have a minimum, and the methods cannot be used.In this paper, we show that there is a strong relationship between and the frequency resolution 2 wpThat is, as we modify f Δ , we obtain graphs of vs n that present at least one minimum. The spectrum obtained with this optimal number of parameters, always reproduces the frequency information of the original signal. In this paper, we present basically the signal processing of the data obtained in a Rayleigh scattering experiment on a supersonic jet that has also been designed by the authors.2 wp σ

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Shock Wave—Turbulence Interactions

Cited by 244 publications

References 81 publications

Numerical investigation of the compressible flow past an aerofoil

Numerical investigation of the compressible flow past an aerofoil

Richtmyer–Meshkov instability: theory of linear and nonlinear evolution

Optimization of Parametric Periodograms for the Study of Density Fluctuations in a Supersonic Jet

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