Flow properties of a supersonic turbulent boundary layer with wall roughness

Latin, Robert M.; Bowersox, Rodney D. W.

doi:10.2514/3.14617

Cited by 5 publications

(18 citation statements)

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“…see Nikuradse (1933), Perry, Schofield & Joubert (1969), Perry, Lim & Henbest (1987), Schlichting (1955), Ligrani & Moffat (1986), Jimenez (2004), Shockling, Allen & Smits (2006) and Schultz & Flack (2007). These studies have shown that surface roughness has a direct effect on the inner region of the Luker et al (2000) M = 2.7, Square roughness, Latin & Bowersox (2000) M = 2.7, 2D Bar roughness, Latin & Bowersox (2000) M = 0, Smooth, Klebanoff (1954) law of the wall and is often described by the single roughness Reynolds number parameter. Nikuradse (1933) demonstrated that for low-speed flows, sand-grain generated roughness increased the velocity defect and skin friction, and shifted the velocity law of the wall plot downward.…”

Section: Supersonic Rough Wall Boundary Layersmentioning

confidence: 99%

“…The current understanding of high-speed rough-wall mean and surface flow processes is founded, to a large degree, in applying compressibility scaling to the corresponding low-speed incompressible database (e.g. see Liepmann & Goddard 1957;Goddard 1959;Morkovin 1961;Reda, Ketter & Fan 1975;Berg 1979;Latin & Bowersox 2000, 2002. Incompressible rough-wall boundary layers have been the subject of considerable attention; e.g.…”

Section: Supersonic Rough Wall Boundary Layersmentioning

confidence: 99%

“…High-speed studies that include turbulence data are less common. The high-speed rough-wall Reynolds shear stress measurements of Latin & Bowersox (2000) are compared to representative low-speed data along with additional high-speed smooth wall data in figure 1(b). In figure 1(b), τ xy = −ρu v and τ w = ρ w U 2 τ .…”

Section: Supersonic Rough Wall Boundary Layersmentioning

confidence: 99%

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Response of supersonic turbulent boundary layers to local and global mechanical distortions

et al. 2009

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The response of the mean and turbulent flow structure of a supersonic high-Reynolds-number turbulent boundary layer flow subjected to local and global mechanical distortions was experimentally examined. Local disturbances were introduced via small-scale wall patterns, and global distortions were induced through streamline curvature-driven pressure gradients. Local surface topologies included k-type diamond and d-type square elements; a smooth wall was examined for comparison purposes. Three global distortions were studied with each of the three surface topologies. Measurements included planar contours of the mean and fluctuating velocity via particle image velocimetry, Pitot pressure profiles, pressure sensitive paint and Schlieren photography. The velocity data were acquired with sufficient resolution to characterize the mean and turbulent flow structure and to examine interactions between the local surface roughness distortions and the imposed pressure gradients on the turbulence production. A strong response to both the local and global distortions was observed with the diamond elements, where the effect of the elements extended into the outer regions of the boundary layer. It was shown that the primary cause for the observed response was the result of local shock and expansion waves modifying the turbulence structure and production. By contrast, the square elements showed a less pronounced response to local flow distortions as the waves were significantly weaker. However, the frictional losses were higher for the blunter square roughness elements. Detailed quantitative characterizations of the turbulence flow structure and the associated production mechanisms are described herein. These experiments demonstrate fundamental differences between supersonic and subsonic rough-wall flows, and the new understanding of the underlying mechanisms provides a scientific basis to systematically modify the mean and turbulence flow structure all the way across supersonic boundary layers.

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Section: Supersonic Rough Wall Boundary Layersmentioning

confidence: 99%

Section: Supersonic Rough Wall Boundary Layersmentioning

confidence: 99%

Section: Supersonic Rough Wall Boundary Layersmentioning

confidence: 99%

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Response of supersonic turbulent boundary layers to local and global mechanical distortions

et al. 2009

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“…( , ) = ( , ) , (6) where Eavg is the average radiation of the PCB surface and E(i,j) corresponds to the local radiation levels in DL. As each PCB is unique with specific non-uniformities, each surface has an individual heating signature.…”

Section: Non-uniform Heating Correctionmentioning

confidence: 99%

“…In contrast to the investigations performed for subsonic flows, the data on the effect of surface geometry under supersonic conditions is relatively scarce. Latin and Bowersox (2000) measured the boundary layer properties resulting from several smaller roughness types (e/δ < 0.2), including two-dimensional, square-ribbed roughness elements [6]. It was found that the mean flow and turbulence properties of the supersonic boundary layers are differently affected by two-dimensional, periodic roughness as the turbulence levels increase by up to 25% compared to equivalent, randomly-distributed, three-dimensional sand-grain roughness.…”

Section: Introductionmentioning

confidence: 99%

Investigation of supersonic, large wall roughness elements with QIRT and PIV

Voogt¹,

Oudheusden²,

Schrijer³

2018

Proceedings of the 2018 International Conference on Quantitative InfraRed Thermography

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The aim of the present study is to quantify the influence of large, ribbed wall roughness elements on the mean flow and heat transfer properties of a turbulent, supersonic boundary layer (M = 2.0). Fifteen test geometries, including one smooth and fourteen rough surfaces are tested using Schlieren, PIV and QIRT. Heat transfer measurements were obtained by the heated-thin-foil method, providing a constant heat flux boundary condition. The QIRT setup was designed to yield an accurate mapping of the surface temperature. It was observed that the geometries followed supersonic, singlecavity type flow classifications with clear, distinguishable flow features.

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Supersonic turbulent flows over sinusoidal rough walls

Jouybari

Yuan

et al. 2023

J. Fluid Mech.

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Direct numerical simulations were performed to characterize fully developed supersonic turbulent channel flows over isothermal rough walls. The effect of roughness was incorporated using a level-set/volume-of-fluid immersed boundary method. Turbulence statistics of five channel flows are compared, including one reference case with both walls smooth and four cases with smooth top walls and bottom walls with two-dimensional (2-D) and three-dimensional (3-D) sinusoidal roughnesses. Results reveal a strong dependence of the turbulence on the roughness topography and the associated shock patterns. Specifically, the 2-D geometries generate strong oblique shock waves that propagate across the channel and are reflected back to the rough-wall side. These strong shocks are absent in the smooth-wall channel and are significantly weaker in cases with 3-D roughness geometries, replaced by weak shocklets. At the impingement locations of the shocks on the top wall in the 2-D roughness cases, localized augmentations of turbulence shear production are observed. Such regions of augmented production also exist for the 3-D cases, at a much weaker level. The oblique shock waves are thought to be responsible for a more significant entropy generation for cases with 2-D surfaces than those with 3-D ones, leading to a higher irreversible heat generation and consequently higher temperature values in 2-D roughness cases. In the present supersonic channels, the effects of roughness extend beyond the near-wall layer due to the shocks. This suggests that outer layer similarity may not fully apply to a rough-wall supersonic turbulent flow.

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Flow properties of a supersonic turbulent boundary layer with wall roughness

Cited by 5 publications

References 0 publications

Response of supersonic turbulent boundary layers to local and global mechanical distortions

Response of supersonic turbulent boundary layers to local and global mechanical distortions

Investigation of supersonic, large wall roughness elements with QIRT and PIV

Supersonic turbulent flows over sinusoidal rough walls

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