DNS of Compressible Turbulent Boundary Layers with Adverse Pressure Gradients

Wenzel, Christoph; Peter, Johannes M. F.; Selent, Björn; Weinschenk, Matthias; Rist, Ulrich; Kloker, Markus J.

doi:10.1007/978-3-030-13325-2_14

Cited by 8 publications

(12 citation statements)

References 21 publications

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“…All computations are performed with the compressible high-order in-house DNS code ; fundamentals are described in Babucke (2009), Linn & Kloker (2008, 2011), Keller & Kloker (2014, 2016) and Wenzel et al. (2018 a ). With the velocity vector with components in the streamwise, wall-normal and spanwise directions , and , the dimensionless solution vector is , where and are the density and the total energy, respectively.…”

Section: Methodology and Numerical Set-upmentioning

confidence: 99%

“…At the inflow, a digital-filtering synthetic-eddy-method (SEM) approach is used to generate an unsteady, turbulent inflow condition, see Wenzel et al. (2018 b ) or Wenzel (2019). The spanwise direction is treated as periodic.…”

Section: Methodology and Numerical Set-upmentioning

confidence: 99%

“…The sponge zone fixes the constant pressure region in the far field through the inflow region, which otherwise is strongly influenced by the retroactive effect of the PG applied further downstream. Only in the streamwise direction, geometrical grid stretching is applied to the numerical grid in the outflow region, see Wenzel (2019).…”

Section: Methodology and Numerical Set-upmentioning

confidence: 99%

“…The subsonic pressure distributions are fixed by the subsonic free-stream BC to the prescribed values in figure 3( a ) and thus also approximately the streamwise velocity component in figure 3( b ). The supersonic initial distributions are adapted by the free-stream BC in such a way that the pressure at the far-field boundary matches the pressure of the resulting flow field inside the domain, see Franko & Lele (2014) and Wenzel (2019). The resulting pressure distributions still follow an approximated power-law relation (blue/cyan for the prescribed distributions , grey for the resulting distributions , only given for the and case).…”

Section: Methodology and Numerical Set-upmentioning

confidence: 99%

“…Caused by the non-characteristic behaviour of this BC, the additional application of numerical grid stretching and filtering and/or additional sponge zones is necessary if sound-wave reflection should be suppressed. At the inflow, a digital-filtering synthetic-eddy-method (SEM) approach is used to generate an unsteady, turbulent inflow condition, see Wenzel et al (2018b) or Wenzel (2019). The spanwise direction is treated as periodic.…”

Section: Subsonic Casesmentioning

confidence: 99%

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Self-similar compressible turbulent boundary layers with pressure gradients. Part 1. Direct numerical simulation and assessment of Morkovin’s hypothesis

et al. 2019

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A direct numerical simulation study of self-similar compressible flat-plate turbulent boundary layers (TBLs) with pressure gradients (PGs) has been performed for inflow Mach numbers of 0.5 and 2.0. All cases are computed with smooth PGs for both favourable and adverse PG distributions (FPG, APG) and thus are akin to experiments using a reflected-wave set-up. The equilibrium character allows for a systematic comparison between sub- and supersonic cases, enabling the isolation of pure PG effects from Mach-number effects and thus an investigation of the validity of common compressibility transformations for compressible PG TBLs. It turned out that the kinematic Rotta–Clauser parameter $\unicode[STIX]{x1D6FD}_{K}$ calculated using the incompressible form of the boundary-layer displacement thickness as length scale is the appropriate similarity parameter to compare both sub- and supersonic cases. Whereas the subsonic APG cases show trends known from incompressible flow, the interpretation of the supersonic PG cases is intricate. Both sub- and supersonic regions exist in the boundary layer, which counteract in their spatial evolution. The boundary-layer thickness $\unicode[STIX]{x1D6FF}_{99}$ and the skin-friction coefficient $c_{f}$, for instance, are therefore in a comparable range for all compressible APG cases. The evaluation of local non-dimensionalized total and turbulent shear stresses shows an almost identical behaviour for both sub- and supersonic cases characterized by similar $\unicode[STIX]{x1D6FD}_{K}$, which indicates the (approximate) validity of Morkovin’s scaling/hypothesis also for compressible PG TBLs. Likewise, the local non-dimensionalized distributions of the mean-flow pressure and the pressure fluctuations are virtually invariant to the local Mach number for same $\unicode[STIX]{x1D6FD}_{K}$-cases. In the inner layer, the van Driest transformation collapses compressible mean-flow data of the streamwise velocity component well into their nearly incompressible counterparts with the same $\unicode[STIX]{x1D6FD}_{K}$. However, noticeable differences can be observed in the wake region of the velocity profiles, depending on the strength of the PG. For both sub- and supersonic cases the recovery factor was found to be significantly decreased by APGs and increased by FPGs, but also to remain virtually constant in regions of approximated equilibrium.

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Section: Methodology and Numerical Set-upmentioning

confidence: 99%

Section: Methodology and Numerical Set-upmentioning

confidence: 99%

Section: Methodology and Numerical Set-upmentioning

confidence: 99%

Section: Methodology and Numerical Set-upmentioning

confidence: 99%

Section: Subsonic Casesmentioning

confidence: 99%

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Self-similar compressible turbulent boundary layers with pressure gradients. Part 1. Direct numerical simulation and assessment of Morkovin’s hypothesis

et al. 2019

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Application of a JPEG 2000-Based Data Compression Algorithm to DNS of Compressible Turbulent Boundary Layers Up to $$Re_\theta =6600$$

Wenzel

Vogler²,

Peter

et al. 2021

High Performance Computing in Science and Engineering '20

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Control of laminar breakdown in a supersonic boundary layer employing streaks

2021

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In this study direct numerical simulations are employed to investigate the effects of various parameters on the laminar-flow-control capabilities of narrowly spaced streaks in a supersonic boundary layer at Mach $2.0$ . Previous work by Sharma et al. (J. Fluid Mech., vol. 873, 2019, pp. 1072–1089) has found these streak modes, excited by a spanwise blowing-and-suction strip, to be highly effective at delaying pure oblique-type breakdown. In the present work it is shown that spectrum-enriching subharmonic modes, relevant with increasing running-length Reynolds number, do not destroy the controlling mechanism, and also a complex breakdown scenario, triggered by a multi-frequency point source, is found to be effectively controlled. Moreover, the control-streak excitation by roughness elements is compared in detail with the blowing-and-suction method, revealing relevant differing features.

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DNS of Compressible Turbulent Boundary Layers with Adverse Pressure Gradients

Cited by 8 publications

References 21 publications

Self-similar compressible turbulent boundary layers with pressure gradients. Part 1. Direct numerical simulation and assessment of Morkovin’s hypothesis

Self-similar compressible turbulent boundary layers with pressure gradients. Part 1. Direct numerical simulation and assessment of Morkovin’s hypothesis

Application of a JPEG 2000-Based Data Compression Algorithm to DNS of Compressible Turbulent Boundary Layers Up to $$Re_\theta =6600$$

Control of laminar breakdown in a supersonic boundary layer employing streaks

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