NO PLIF Study of Hypersonic Transition over a Discrete Hemispherical Roughness Element

Danehy, Paul M.; Bathel, Brett F.; Ivey, Christopher B.; Inman, Jennifer A.; Jones, Stephen B.

doi:10.2514/6.2009-394

Cited by 44 publications

(40 citation statements)

References 10 publications

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“…For the runs in Test 443 the imperfections are described in Ref. 9. For Test 463, the imperfections were the same as for Test 462 and are described in Ref.…”

Section: Experiments and Analysis Descriptionmentioning

confidence: 99%

“…In previous related work, flat plate flows over a triangular trip and a rectangular fence 8 as well as a hemispherical roughness element 9 were reported. In these papers, different methods of seeding NO were studied and analyzed to determine which method had the minimal impact on the flowfield.…”

Section: Introductionmentioning

confidence: 99%

“…The 10 Hz system is detailed in Ref. 9, where use of the system to obtain thin-laser-sheet images is described. This system produced a laser sheet about 0.2 mm thick.…”

mentioning

confidence: 99%

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High-Speed PLIF Imaging of Hypersonic Transition over Discrete Cylindrical Roughness

Danehy

Ivey

Inman

et al. 2010

48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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Transitional flow over cylindrical protuberances attached to a flat plate has been studied in a hypersonic wind tunnel. The tests were performed in the 31-Inch Mach 10 Air Tunnel at NASA Langley Research Center. Cylindrical protuberances with 4-mm diameter and heights of 1, 2, and 4 mm, were attached to the flat plate. The plate angle of attack and tunnel stagnation pressure were varied to achieve desired combinations of boundary layer edge Mach number and the boundary layer thickness. Several different types of flow visualization based on nitric oxide planar laser-induced fluorescence (NO PLIF) were used. A 10-Hz NO PLIF system was used to produce a thin laser sheet. This laser sheet was oriented perpendicular to the flat plate on some runs and parallel to the flat plate on others. A thick laser sheet was also used in some runs to provide visualization of entire flow structures inside the boundary layer. Viewing the PLIF intensity generated with the thick laser sheet using two cameras allowed stereoscopic visualization of the flow. In post processing, these images were combined to produce anaglyphs. Viewing these anaglyphs through blue and red 3D-glasses allows the three-dimensional flow structures to be observed. Another measurement system was a MHz-rate NO PLIF imaging system. Both PLIF measurement systems have better than one microsecond time resolution, which is fast enough to freeze the flow. The MHz system allows subsequent images to be obtained at one or two microsecond time intervals, resulting in movies of the flow. The data reported in this paper show the size, shape, and speed of flow structures in transitional hypersonic boundary layer flows and will provide valuable comparison data for computations of these flows.

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“…For the runs in Test 443 the imperfections are described in Ref. 9. For Test 463, the imperfections were the same as for Test 462 and are described in Ref.…”

Section: Experiments and Analysis Descriptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

High-Speed PLIF Imaging of Hypersonic Transition over Discrete Cylindrical Roughness

Danehy

Ivey

Inman

et al. 2010

48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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“…DNS results permits to better understand physical mechanics behind induced transition but few experimental data are available as benchmark. Recently, Iyev and Mahesh [21] performed DNS replicating the experiments carried out by Danehy et al [18]. In their paper they report a complete analysis of the wake in front and behind a hemispherical roughness elements with ℎ⁄ > 1 at three Mach number equal to 3.37, 5.26 and 8.23.…”

Section: Introductionmentioning

confidence: 99%

“…laser based and image based technique, is a necessity. Recently, in the Mach 10 wind tunnel at NASA Langley was applied the Nitrix oxide (NO) planar-laser induced fluorescence to investigate the hypersonic flow over a flat plate with and without a 2 mm radius hemispherical trip [18] and with a cylindrical roughness [19] showing interesting instantaneous features. The improvement of the experimental technique coupled with the availability of greater computational resources have enabled the use of direct numerical simulation (DNS) to study transition [20].…”

Section: Introductionmentioning

confidence: 99%

IR thermography investigation on roughness induced transition in high-speed flows

Avallone¹,

Schrijer²,

Cardone³

2014

Proceedings of the 2014 International Conference on Quantitative InfraRed Thermography

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Boundary layer transition in high-speed flows is a phenomenon that despite extensive research over the years is still extremely hard to predict. The presence of protrusions or gaps can lead to an accelerated laminar-to-turbulent transition enhancing the thermal loads and the skin friction coefficient. In the current investigation, high-resolution heat transfer measurements using infrared thermography are performed on the flow past several different roughness geometries (cylinders and pizza-box) at free stream Mach number equal to 7.5 and three unit Reynolds number (14 • 10 , 11 • 10 , 8 • 10 ). The roughness elements are applied on a plate that is oriented at a 5° angle of attack with respect to the flow direction. For each Reynolds number the roughness element is positioned at 30 mm and at 60 mm from the leading edge. The measurements establish the roughness effectiveness in promoting transition and they provide insight into the flow topology.

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Tomographic PIV investigation of roughness-induced transition in a hypersonic boundary layer

Avallone

Schrijer

et al. 2014

Exp Fluids

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The disturbance generated by roughness elements in a hypersonic laminar boundary layer is investigated, with attention to its three-dimensional properties. The transition of the boundary layer is inspected with tomographic particle image velocimetry that is applied for the first time at Mach 7.5 inside a short duration hypersonic wind tunnel. A low aspect ratio cylindrical roughness element is installed on a flat plate, and experiments are conducted downstream of the element describing the mean velocity field and the turbulent fluctuations. Details of the experimental procedure needed to realize these measurements are discussed, along with the fluid dynamic behaviour of the perturbed hypersonic boundary layer

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NO PLIF Study of Hypersonic Transition over a Discrete Hemispherical Roughness Element

Cited by 44 publications

References 10 publications

High-Speed PLIF Imaging of Hypersonic Transition over Discrete Cylindrical Roughness

High-Speed PLIF Imaging of Hypersonic Transition over Discrete Cylindrical Roughness

IR thermography investigation on roughness induced transition in high-speed flows

Tomographic PIV investigation of roughness-induced transition in a hypersonic boundary layer

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