Journal ArticleDOI
Measurements in a separation bubble on an airfoil using laser velocimetry
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In this paper, an experimental investigation was conducted to measure the reverse flow within the transitional separation bubble that forms on an airfoil at low Reynolds numbers, and a new correlation was proposed based on zero velocity position, since the Schmidt (1986) correlations fail in the turbulent portion of the bubble.Abstract:
An experimental investigation was conducted to measure the reverse flow within the transitional separation bubble that forms on an airfoil at low Reynolds numbers. Measurements were used to determine the effect of the reverse flow on integrated boundary-layer parameters often used to model the bubble. Velocity profile data were obtained on an NACA 663-018 airfoil at angle of attack of 12 deg and a chord Reynolds number of 140,000 using laser Doppler and single-sensor hot-wire anemometry. A new correlation is proposed based on zero velocity position, since the Schmidt (1986) correlations fail in the turbulent portion of the bubble.read more
Citations
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Journal ArticleDOI
Aerodynamics of small vehicles
TL;DR: In this article, the aerodynamic problems that must be addressed in order to design a successful small aerial vehicle are described, including the effects of Reynolds number and aspect ratio (AR) on the design and performance of fixed-wing vehicles.
Journal ArticleDOI
Investigations on controlled transition development in a laminar separation bubble by means of LDA and PIV
TL;DR: In this paper, a small-amplitude Tollmien-Schlichting wave (TS wave) was introduced into the boundary layer without (case I) and with (case II) spanwise forcing of steady 3D disturbances.
Journal ArticleDOI
Investigation of the vortex induced unsteadiness of a separation bubble via time-resolved and scanning PIV measurements
TL;DR: In this paper, a 3D separation bubble on the suction side of an SD7003 airfoil is considered and the effect of the free-stream turbulence on the formation of large scale vortices at the downstream end of the bubble.
Journal ArticleDOI
On the origin of the inflectional instability of a laminar separation bubble
Sourabh S. Diwan,O. N. Ramesh +1 more
TL;DR: In this paper, an experimental and theoretical study of a laminar separation bubble and the associated linear stability mechanisms was performed over a flat plate kept in a wind tunnel, with an imposed pressure gradient typical of an aerofoil.
Journal ArticleDOI
Vortex formation and vortex breakup in a laminar separation bubble
Olaf Marxen,M. Lang,Ulrich Rist +2 more
TL;DR: In this paper, an in-depth characterization of the vortex formation and breakup process in a forced laminar separation bubble is presented, exploiting the largely periodic character of the flow in time as well as in the spanwise direction.
References
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Book
Viscous Fluid Flow
TL;DR: In this article, the stability of Laminar Boundary Layer Flow Appendices has been investigated in Cylindrical and Spherical Coordinates of Incompressible Newtonian Fluids.
Journal ArticleDOI
Further solutions of the Falkner-Skan equation
TL;DR: In this paper, the possibility of further solutions to the Falkner-Skan equation f′′′ + ff″ + β(1 − f′2) = 0, in addition to those found by Hartree, is investigated.
Journal ArticleDOI
Boundary-layer measurements on an airfoil at low Reynolds numbers
M. Brendel,Thomas J. Mueller +1 more
TL;DR: Etude experimentale des caracteristiques des bulles de decollement de transition par anemometrie laser and a fil chaud as mentioned in this paper, et al.
Journal ArticleDOI
Low-Reynolds-number airfoil design for the M.I.T. Daedalus prototype- A case study
TL;DR: In this paper, the aerodynamic wing design of the Light Eagle is presented, with three different airfoils, designed for chord Reynolds numbers of 500,000,375,000 and 250,000 were used across the wingspan.
Low Reynolds Number Vehicles
TL;DR: In this paper, the authors present the present status and future possibility of airfoil design and evaluation at subcritical speeds to meet the needs for these applications, including remotely piloted vehicles (RPV's), sailplanes, ultra-light man-carrying/man-powered aircraft, mini-RPVs at low altitudes and wind turbines/propellers.