Experimental investigation of separated shear layer from a leading edge subjected to various angles of attack with tail flap deflections

Anand, K.; Sarkar, S.

doi:10.1007/s12046-015-0341-2

Cited by 1 publication

(2 citation statements)

References 17 publications

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“…The topology and geometry of the vortex cores investigated in their study is found to agree with earlier results available in the literature. The instability analysis of the boundary layer separated from the leading-edge for a wide range of imposed pressure gradients and free-stream angles was studied by Anand 30 by conducting experiments on a flat-plate model. It was reported that the roll up of the shear layer at lower angle of attack occurs due to the inviscid instability mechanism K-H , while for higher angles, it bypasses the K-H mechanism.…”

Section: Topology Of Laminar Separation Bubblementioning

confidence: 99%

“…10–12 As the laminar shear layer is highly susceptible to background disturbances, the shear layer rolls up following a small kink in the streak line. 13,30 The first appearance of this small perturbation in the streak line is identified as transition and is notified as “ t. ” From the figure, it is observed that a small streak in the shear layer is followed by a roll-up structure. Smoke flow visualization on a two-dimensional model by Hiller and Cherry 12 also reported the visibility of large vortical structures at ∼60% of its bubble length.…”

Section: Surface Pressurementioning

confidence: 99%

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Characteristics of a separated flow past a semicircular leading-edge airfoil model under different imposed pressure gradient

Anand

Ganesh

2021

Proceedings of the Institution of Mechanical Engineers, Part G:

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The effect of pressure gradient on a separated boundary layer past the leading edge of an airfoil model is studied experimentally using electronically scanned pressure (ESP) and particle image velocimetry (PIV) for a Reynolds number ( Re) of 25,000, based on leading-edge diameter ( D). The features of the boundary layer in the region of separation and its development past the reattachment location are examined for three cases of β (−30°, 0°, and +30°). The bubble parameters such as the onset of separation and transition and the reattachment location are identified from the averaged data obtained from pressure and velocity measurements. Surface pressure measurements obtained from ESP show a surge in wall static pressure for β = −30° (flap deflected up), while it goes down for β = +30° (flap deflected down) compared to the fundamental case, β = 0°. Particle image velocimetry results show that the roll up of the shear layer past the onset of separation is early for β = +30°, owing to higher amplification of background disturbances compared to β = 0° and −30°. Downstream to transition location, the instantaneous field measurements reveal a stretched, disoriented, and at instances bigger vortices for β = +30°, whereas a regular, periodically shed vortices, keeping their identity past the reattachment location, is observed for β = 0° and −30°. Above all, this study presents a new insight on the features of a separation bubble receiving a disturbance from the downstream end of the model, and these results may serve as a bench mark for future studies over an airfoil under similar environment.

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Section: Topology Of Laminar Separation Bubblementioning

confidence: 99%