Effects of Motion History on Leading Edge Separation for an Airfoil Pitching to Large Angles of Attack

Effects of Motion History on Leading Edge Separation for an Airfoil Pitching to Large Angles of Attack PDF Author: Todd Allen Brown
Publisher:
ISBN:
Category : Aerofoils
Languages : en
Pages : 238

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Effects of Motion History on Leading Edge Separation for an Airfoil Pitching to Large Angles of Attack

Effects of Motion History on Leading Edge Separation for an Airfoil Pitching to Large Angles of Attack PDF Author: Todd Allen Brown
Publisher:
ISBN:
Category : Aerofoils
Languages : en
Pages : 238

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Dynamic Stall of Rapidly Pitching Airfoils

Dynamic Stall of Rapidly Pitching Airfoils PDF Author: Charles Paul Gendrich
Publisher:
ISBN:
Category : Aerofoils
Languages : en
Pages : 344

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Flow Control

Flow Control PDF Author: Mohamed Gad-el-Hak
Publisher: Springer Science & Business Media
ISBN: 3540696725
Category : Science
Languages : en
Pages : 533

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No be certain it can is not based mathematics. knowledge if upon da Vinci, (Leonardo 1452 1519) the humankind. Thinking is one greatest of Joys of Galilei, (Galileo 1564 1642) Now I think is to be the root all hydrodynamics and is at of physical science, second the to none in its mathematics. present beauty of Thomson (William (Lord Kelvin), 1824 1907) The book contains the lecture notes of of the nine instructors at present eight the short Flow Control: Fundamentals and which held course was Practices, in the week 24 28 June and Carg6se, Corsica, France, during 1996, repeated at the of Notre 9 13 1996. University Dame, Indiana, September Following the week in the course a on same was held. Corsica, 5 day workshop topic Selected from the scheduled to 1998 workshop are papers appear early special volume of the International Journal Heat Thermo of Experimental Transfer, and Fluid All Mechanics. three events were Jean Paul dynamics, organized by Bonnet of Universit6 de Andrew Pollard of Univer Poitiers, France, Queen's at and Mohamed Gad el Hak of the of sity Kingston, Canada, University Notre U.S.A.

Unsteady Flow Field of Large-Amplitude Pitching Airfoils

Unsteady Flow Field of Large-Amplitude Pitching Airfoils PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 33

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This research program investigated the physical mechanisms involved in the onset of leading edge separation when airfoils pitch to high angles of attack. Both constant pitch rate and variable pitch rate motions were considered. The highlights of results from a combined experimental and computational effort are described in this report. The conclusions from this research indicate the need for boundary-layer resolved measurements of the flow behavior near the leading edge and the evolution of the reverse flow regions on the suction surface. Furthermore, the deliberate shaping of the pitch trajectory for the purpose of optimization of separation delay is suggested as one way to manage the flow and aerodynamic behavior of an airfoil. Dynamic Stall, Unsteady Separation.

Compressibility Effects on Dynamic Stall of Airfoils Undergoing Rapid Transient Pitching Motion

Compressibility Effects on Dynamic Stall of Airfoils Undergoing Rapid Transient Pitching Motion PDF Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781722115975
Category :
Languages : en
Pages : 28

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The research was carried out in the Compressible Dynamic Stall Facility, CDSF, at the Fluid Mechanics Laboratory (FML) of NASA Ames Research Center. The facility can produce realistic nondimensional pitch rates experienced by fighter aircraft, which on model scale could be as high as 3600/sec. Nonintrusive optical techniques were used for the measurements. The highlight of the effort was the development of a new real time interferometry method known as Point Diffraction Interferometry - PDI, for use in unsteady separated flows. This can yield instantaneous flow density information (and hence pressure distributions in isentropic flows) over the airfoil. A key finding is that the dynamic stall vortex forms just as the airfoil leading edge separation bubble opens-up. A major result is the observation and quantification of multiple shocks over the airfoil near the leading edge. A quantitative analysis of the PDI images shows that pitching airfoils produce larger suction peaks than steady airfoils at the same Mach number prior to stall. The peak suction level reached just before stall develops is the same at all unsteady rates and decreases with increase in Mach number. The suction is lost once the dynamic stall vortex or vortical structure begins to convect. Based on the knowledge gained from this preliminary analysis of the data, efforts to control dynamic stall were initiated. The focus of this work was to arrive at a dynamically changing leading edge shape that produces only 'acceptable' airfoil pressure distributions over a large angle of attack range. Chandrasekhara, M. S. and Platzer, M. F. Ames Research Center AF-AFOSR-0012-90; AF-AFOSR-0007-91; AF-AFOSR-0004-92; AF PROJ. 2307...

Effects of Compressibility, Pitch Rate and Reynolds Number on Unsteady Incipient Leading-edge Boundary Layer Separation Over a Pitching Airfoil

Effects of Compressibility, Pitch Rate and Reynolds Number on Unsteady Incipient Leading-edge Boundary Layer Separation Over a Pitching Airfoil PDF Author: Pushkar Ghosh Choudhuri
Publisher:
ISBN:
Category :
Languages : en
Pages : 208

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Comparison of Pitching Moments Produced by Plain Flaps and by Spoilers and Some Aerodynamic Characteristics of an NACA 23012 Airfoil with Various Types of Aileron

Comparison of Pitching Moments Produced by Plain Flaps and by Spoilers and Some Aerodynamic Characteristics of an NACA 23012 Airfoil with Various Types of Aileron PDF Author: Paul E. Purser
Publisher:
ISBN:
Category : Aerodynamics
Languages : en
Pages : 26

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An analysis and comparison has been made of the pitching moment characteristics of airfoils with plain flaps and spoilers. Sectional characteristics of airfoil having retractable slotted flap with plain, slot-lip, or retractable ailerons are presented for a large range of aileron deflections. The analysis indicated that pitching moments produced by spoilers were less positive than those produced by plain flaps of equal effectiveness, also that pitching moments created by the spoiler increased less with the Mach number than similar moments produced by plain flaps. Positive values of pitching moment decreased as devices were located nearer airfoil leading edge.

Effects of Compressibility, Pitch Rate and Reynolds Number on Unsteady Incipient Leading-edge Boundary Layer Separation Over a Pitching Airfoil

Effects of Compressibility, Pitch Rate and Reynolds Number on Unsteady Incipient Leading-edge Boundary Layer Separation Over a Pitching Airfoil PDF Author: Pushkar Ghosh Choudhuri
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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2-D Unsteady Leading Edge Separation on a Pitching Airfoil

2-D Unsteady Leading Edge Separation on a Pitching Airfoil PDF Author: Doyle D. Knight
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports PDF Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 500

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