The Experts below are selected from a list of 10425 Experts worldwide ranked by ideXlab platform
Alexander A Zheltovodov - One of the best experts on this subject based on the ideXlab platform.
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large eddy simulation of shock wave turbulent boundary layer interaction
Journal of Fluid Mechanics, 2006Co-Authors: Maxim S Loginov, N A Adams, Alexander A ZheltovodovAbstract:Well-resolved Large-Eddy Simulations (LES) are performed in order to investigate flow phenomena and turbulence structure of the turbulent boundary layer along a supersonic compression-decompression ramp. For the first time it was possible to reproduce directly a reference experiment with a Free-Stream Mach Number of M = 2.95 and a Reynolds Number based on the incoming boundary-layer thickness of Re = 63560. The effect of subgrid-scales is modeled by the approximate deconvolution model. An analysis of the results shows a good agreement with reference experiment in terms of mean quantities and turbulence structure. The computational data confirm theoretical and experimental results on fluctuation-amplification across the interaction region. In the wake of the main shock a shedding of shocklets is observed. The temporal behavior of the coupled shock-separation system agrees well with experimental data. The simulation data provide indications for a large-scale shock motion. Also the existence of three-dimensional large-scale streamwise structures, commonly referred to as Gortler-like vortices, is confirmed. The LES provide a reliable and detailed flow information, which helped to improve the understanding of shock-boundary-layer interaction considerably.
P Dupont - One of the best experts on this subject based on the ideXlab platform.
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a scaling analysis for turbulent shock wave boundary layer interactions
Journal of Fluid Mechanics, 2013Co-Authors: L J Souverein, P G Bakker, P DupontAbstract:A model based on mass conservation properties is developed for shock-wave/boundarylayer interactions (SWBLIs), aimed at reconciling the observed great diversity in flow organization documented in the literature, induced by variations in interaction geometry and aerodynamic conditions. It is the basis for a scaling approach for the interaction length that is valid independent of the geometry of the flow (considering compression corners and incident-reflecting shock interactions). As part of the analysis, a scaling argument is proposed for the imposed pressure jump that depends principally on the Free-Stream Mach Number and the flow deflection angle. Its interpretation as a separation criterion leads to a successful classification of the separation states for turbulent SWBLIs (attached, incipient or separated). In addition, the dependence of the interaction length on the Reynolds Number and the Mach Numbers is accounted for. A large compilation of available data provides support for the validity of the model. Some general properties on the state of the flow are derived, independent of the geometry of the flow and for a wide range of Mach Numbers and Reynolds Numbers.
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application of a dual plane particle image velocimetry dual piv technique for the unsteadiness characterization of a shock wave turbulent boundary layer interaction
Measurement Science and Technology, 2009Co-Authors: L J Souverein, B W Van Oudheusden, F Scarano, P DupontAbstract:The unsteady organization and temporal dynamics of the interaction between a planar shock wave impinging on a turbulent boundary layer at a Free-Stream Mach Number of Me = 1.69 is investigated experimentally by means of dual-plane particle image velocimetry (dual-PIV). Two independent PIV systems were combined in a two-component mode to obtain instantaneous velocity fields separated by a prescribed small time delay. This enables us to obtain, in addition to mean and statistical flow properties, also instantaneously time-resolved data to characterize the temporal dynamics of the flow phenomenon in terms of time scales, temporal correlations and convective velocities. The characteristic time scales for the incoming boundary layer, the separation region and the reflected shock are determined by means of the temporal auto-correlation coefficient in the complete flow field for a range of time delays from 5 ?s to 2000 ?s. These auto-correlation fields are used to quantify the time scales in selected regions of the flow, with special interest for the vortex shedding and the low frequency reflected shock dynamics. This permits resolving the dominant time scales within the boundary layer and the interaction region.
Stefan Hickel - One of the best experts on this subject based on the ideXlab platform.
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on the transition between regular and irregular shock patterns of shock wave boundary layer interactions
Journal of Fluid Mechanics, 2015Co-Authors: Jan Matheis, Stefan HickelAbstract:The reflection of strong oblique shock waves at turbulent boundary layers is studied numerically and analytically. A particular emphasis is put on the transition between regular shock-wave/boundary-layer interaction (SWBLI) and Mach reflection (irregular SWBLI). The classical two- and three-shock theory and a generalised form of the free interaction theory are used for the analysis of well-resolved large-eddy simulations (LES) and for the derivation of stability criteria. We found that at a critical deflection angle across the incident shock wave, the perturbations related to the turbulent boundary layer cause bi-directional transition processes between regular and irregular shock patterns for a Free-Stream Mach Number of . Computational results show that the mean deflection angle across the separation shock is decoupled from the incident shock wave and can be accurately modelled by the generalised free interaction theory. On the basis of these observations, and the von Neumann and detachment criteria for the asymmetric intersection of shock waves, we derive the critical incident shock deflection angles at which the shock pattern may/must become irregular. Numerical data for a Free-Stream Mach Number of confirm the existence of the dual-solution domain predicted by theory.
L J Souverein - One of the best experts on this subject based on the ideXlab platform.
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a scaling analysis for turbulent shock wave boundary layer interactions
Journal of Fluid Mechanics, 2013Co-Authors: L J Souverein, P G Bakker, P DupontAbstract:A model based on mass conservation properties is developed for shock-wave/boundarylayer interactions (SWBLIs), aimed at reconciling the observed great diversity in flow organization documented in the literature, induced by variations in interaction geometry and aerodynamic conditions. It is the basis for a scaling approach for the interaction length that is valid independent of the geometry of the flow (considering compression corners and incident-reflecting shock interactions). As part of the analysis, a scaling argument is proposed for the imposed pressure jump that depends principally on the Free-Stream Mach Number and the flow deflection angle. Its interpretation as a separation criterion leads to a successful classification of the separation states for turbulent SWBLIs (attached, incipient or separated). In addition, the dependence of the interaction length on the Reynolds Number and the Mach Numbers is accounted for. A large compilation of available data provides support for the validity of the model. Some general properties on the state of the flow are derived, independent of the geometry of the flow and for a wide range of Mach Numbers and Reynolds Numbers.
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application of a dual plane particle image velocimetry dual piv technique for the unsteadiness characterization of a shock wave turbulent boundary layer interaction
Measurement Science and Technology, 2009Co-Authors: L J Souverein, B W Van Oudheusden, F Scarano, P DupontAbstract:The unsteady organization and temporal dynamics of the interaction between a planar shock wave impinging on a turbulent boundary layer at a Free-Stream Mach Number of Me = 1.69 is investigated experimentally by means of dual-plane particle image velocimetry (dual-PIV). Two independent PIV systems were combined in a two-component mode to obtain instantaneous velocity fields separated by a prescribed small time delay. This enables us to obtain, in addition to mean and statistical flow properties, also instantaneously time-resolved data to characterize the temporal dynamics of the flow phenomenon in terms of time scales, temporal correlations and convective velocities. The characteristic time scales for the incoming boundary layer, the separation region and the reflected shock are determined by means of the temporal auto-correlation coefficient in the complete flow field for a range of time delays from 5 ?s to 2000 ?s. These auto-correlation fields are used to quantify the time scales in selected regions of the flow, with special interest for the vortex shedding and the low frequency reflected shock dynamics. This permits resolving the dominant time scales within the boundary layer and the interaction region.
Maxim S Loginov - One of the best experts on this subject based on the ideXlab platform.
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large eddy simulation of shock wave turbulent boundary layer interaction
Journal of Fluid Mechanics, 2006Co-Authors: Maxim S Loginov, N A Adams, Alexander A ZheltovodovAbstract:Well-resolved Large-Eddy Simulations (LES) are performed in order to investigate flow phenomena and turbulence structure of the turbulent boundary layer along a supersonic compression-decompression ramp. For the first time it was possible to reproduce directly a reference experiment with a Free-Stream Mach Number of M = 2.95 and a Reynolds Number based on the incoming boundary-layer thickness of Re = 63560. The effect of subgrid-scales is modeled by the approximate deconvolution model. An analysis of the results shows a good agreement with reference experiment in terms of mean quantities and turbulence structure. The computational data confirm theoretical and experimental results on fluctuation-amplification across the interaction region. In the wake of the main shock a shedding of shocklets is observed. The temporal behavior of the coupled shock-separation system agrees well with experimental data. The simulation data provide indications for a large-scale shock motion. Also the existence of three-dimensional large-scale streamwise structures, commonly referred to as Gortler-like vortices, is confirmed. The LES provide a reliable and detailed flow information, which helped to improve the understanding of shock-boundary-layer interaction considerably.
