Shock Unsteadiness and Shock Induced Separation at Transonic Flow Over a Bump

Bodin, Olle; Fuchs, László

doi:10.2514/6.2008-4174

Cited by 6 publications

(2 citation statements)

References 4 publications

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“…Studies of unsteady shock motion over hemispheres, however, appear largely absent from the literature, although the closely related geometry of rounded bumps has been the subject of some investigation [8][9][10][11][12][13][14][15]. With the exception of [14], these investigations all concerned two-dimensional bumps, a noteworthy difference from the three-dimensionality of hemispherical geometries.…”

Section: Introductionmentioning

confidence: 92%

Unsteady Shock Motion in a Transonic Flow over a Wall-Mounted Hemisphere

Beresh

Henfling

Spillers

et al. 2013

43rd Fluid Dynamics Conference

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Particle image velocimetry measurements have been conducted for a Mach 0.8 flow over a wall-mounted hemisphere. The flow is strongly separated, with a mean recirculation length exceeding 5 δ and a mean reverse velocity of -0.2 U ∞ . The shock foot was found to typically sit just forward of the apex of the hemisphere and move within a range of about ±10 deg. Conditional averages based upon the shock foot location show that the separation shock is positioned upstream along the hemisphere surface when reverse velocities in the recirculation region are strong and is located downstream when they are weaker. The recirculation region appears smaller when the shock is located farther downstream. No correlation was detected of the incoming boundary layer with the shock position, nor with the wake recirculation velocities. These observations are consistent with recent studies concluding that for large strong separation regions, the dominant mechanism is the instability of the separated flow rather than a direct influence of the incoming boundary layer.

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Section: Introductionmentioning

confidence: 92%

Unsteady Shock Motion in a Transonic Flow over a Wall-Mounted Hemisphere

Beresh

Henfling

Spillers

et al. 2013

43rd Fluid Dynamics Conference

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“…More recently, Brouwer (2016) performed a DNS but at a higher Mach number (0.79 against 0.7 in Bron (2003)) and at an even lower Reynolds number (Re ≈ 1.7 × 10 5 ). The impact of oscillating backpressure on the shock motion has been investigated only by Bodin and Fuchs (2008) using ILES. The results highlighted a hysteretic behavior of the shock.…”

Section: Introductionmentioning

confidence: 99%

Investigation of forced shock-induced separation in transonic channel

Goffart,

Tartinville,

Hirsch

et al. 2023

European Conference on Turbomachinery Fluid Dynamics and Thermodynamics

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This paper presents the results of an implicit large-eddy simulation of the transonic flow over a bump. The conditions are chosen such that the configuration reproduces actual turbomachinery flows: a shock wave develops as in a transonic passage and a fluctuating backpressure is imposed to mimic the perturbations coming from a downstream row. The aim of the study is to investigate the influence of the forced conditions on the flow field, with an emphasis on the harmonic component of the turbulent stresses in the recirculation region. Results indicate that all the flow features (shock motion, wall static pressure, separation and reattachment points) respond primarily to the forcing frequency. Phaseaveraging is employed to extract the coherent component of the flow. It is shown that the harmonic turbulent stresses are organized into different structures and are non-negligible with respect to the mean component. KEYWORDSchannel flow, transonic, forced oscillation, turbulence NOMENCLATURE B l bump length [m] δ 0 reference boundary layer thickness [m] ∆ x , ∆ y , ∆ z grid resolution in the streamwise, wall-normal and spanwise direction [m] ν kinematic viscosity [m 2 /s] U ∞ freestream velocity [m/s] Abbreviations CFL Courant-Friedrichs-Lewy DNS Direct Numerical Simulation FFT Fast Fourier Transform (I)LES (Implicit) Large-Eddy Simulation PDF Probability Density Function (U)RANS (Unsteady) Reynolds-Averaged Navier-Stokes WPSD Weighted Power Spectral Density Superscripts + wall unit ..

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