Author: Katie Kristine Thorne
Publisher:
ISBN:
Category :
Languages : en
Pages : 101
Book Description
An Experimental Investigation of Compressible Dynamic Stall on a 2-D Pitching Airfoil
Author: Katie Kristine Thorne
Publisher:
ISBN:
Category :
Languages : en
Pages : 101
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 101
Book Description
Experimental Investigation of the Formation and Control of the Dynamic-stall Vortex Over a Pitching Airfoil
Author: Md. Ahsanul Karim
Publisher:
ISBN:
Category :
Languages : en
Pages : 322
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 322
Book Description
A Study of Compressibility Effects on Dynamic Stall of Rapidly Pitching Airfoils
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 8
Book Description
Results of recent experimental studies into the effect of compressibility on dynamic stall of oscillating airfoils are reviewed. Stroboscopic schlieren images of the strongly unsteady flow field are presented, showing the development of the dynamic stall vortex. and its progression down the airfoil. The effect of varying free-stream Mach number, and frequency of oscillation of the airfoil are demonstrated, and examples of local supersonic flow are presented including the presence of a shock near the leading edge of the airfoil.
Publisher:
ISBN:
Category :
Languages : en
Pages : 8
Book Description
Results of recent experimental studies into the effect of compressibility on dynamic stall of oscillating airfoils are reviewed. Stroboscopic schlieren images of the strongly unsteady flow field are presented, showing the development of the dynamic stall vortex. and its progression down the airfoil. The effect of varying free-stream Mach number, and frequency of oscillation of the airfoil are demonstrated, and examples of local supersonic flow are presented including the presence of a shock near the leading edge of the airfoil.
An Experimental Study of Dynamic Stall on Advanced Airfoil Sections. Volume 1: Summary of the Experiment
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 108
Book Description
The static and dynamic characteristics of seven helicopter sections and a fixed-wing supercritical airfoil were investigated over a wide range of nominally two-dimensional flow conditions, at Mach numbers up to 0.30 and Reynolds numbers up to 4x10 to the 6th power. Details of the experiment, estimates of measurement accuracy, and test conditions are described in this volume. The results of the experiment show important differences between airfoils, which would otherwise tend to be masked by differences in wind tunnels, particularly in steady cases. All of the airfoils tested provide significant advantages over the conventional NACA 0012 profile. In general, however, the parameters of the unsteady motion appear to be more important than airfoil shape in determining the dynamic-stall airloads.
Publisher:
ISBN:
Category :
Languages : en
Pages : 108
Book Description
The static and dynamic characteristics of seven helicopter sections and a fixed-wing supercritical airfoil were investigated over a wide range of nominally two-dimensional flow conditions, at Mach numbers up to 0.30 and Reynolds numbers up to 4x10 to the 6th power. Details of the experiment, estimates of measurement accuracy, and test conditions are described in this volume. The results of the experiment show important differences between airfoils, which would otherwise tend to be masked by differences in wind tunnels, particularly in steady cases. All of the airfoils tested provide significant advantages over the conventional NACA 0012 profile. In general, however, the parameters of the unsteady motion appear to be more important than airfoil shape in determining the dynamic-stall airloads.
An Experimental Investigation of High Lift/high Rate Aerodynamics of an Unsteady Airfoil
Author: G. M. Graham
Publisher:
ISBN:
Category : Aerofoils
Languages : en
Pages : 102
Book Description
Publisher:
ISBN:
Category : Aerofoils
Languages : en
Pages : 102
Book Description
An Investigation of Airfoil Dynamic Stall with Large Amplitude Motions
Author: Michael S. Francis
Publisher:
ISBN:
Category :
Languages : en
Pages : 158
Book Description
The results of an experimental investigation of airfoil dynamic stall involving large amplitude pitching motions are described. The discussion is focused on constant pitch rate motion histories. Measurements of unsteady surface pressure distributions for both NACA 0012 and NACA 64 sub 1 A012(13) profiles have been employed to infer the onset and evolution of an energetic leading edge separation vortex over a wide range of flow and motion conditions. These data have also been integrated to provide estimates of the time histories of the lift, pressure drag and moment coefficients. The effectiveness of the various motions for achieving lift enhancement has been determined through the introduction of a dimensionless impulse parameter which accounts for both the magnitude and duration of the additional lift increment during the post-stall period. (Author).
Publisher:
ISBN:
Category :
Languages : en
Pages : 158
Book Description
The results of an experimental investigation of airfoil dynamic stall involving large amplitude pitching motions are described. The discussion is focused on constant pitch rate motion histories. Measurements of unsteady surface pressure distributions for both NACA 0012 and NACA 64 sub 1 A012(13) profiles have been employed to infer the onset and evolution of an energetic leading edge separation vortex over a wide range of flow and motion conditions. These data have also been integrated to provide estimates of the time histories of the lift, pressure drag and moment coefficients. The effectiveness of the various motions for achieving lift enhancement has been determined through the introduction of a dimensionless impulse parameter which accounts for both the magnitude and duration of the additional lift increment during the post-stall period. (Author).
Scientific and Technical Aerospace Reports
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 456
Book Description
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 456
Book Description
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
An Experimental Study of Dynamic Stall on Advanced Airfoil Section. Volume 2: Pressure and Force Data
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 662
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 662
Book Description
An Experimental Study of Dynamic Stall on Advanced Airfoil Sections. Volume 2. Pressure and Force Data
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 646
Book Description
Experimentally derived force and moment data are presented for eight airfoil sections that were tested at fixed and varying incidence in a subsonic two-dimensional stream. Airfoil incidence was varied through sinusoidal oscillations in pitch over a wide range of amplitude and frequency. The surface pressure distribution, as well as the lift, drag, and pitching moment derived therefrom, are displayed in a uniform fashion to delineate the static and dynamic characteristics of each airfoil both in and out of stall. (Author).
Publisher:
ISBN:
Category :
Languages : en
Pages : 646
Book Description
Experimentally derived force and moment data are presented for eight airfoil sections that were tested at fixed and varying incidence in a subsonic two-dimensional stream. Airfoil incidence was varied through sinusoidal oscillations in pitch over a wide range of amplitude and frequency. The surface pressure distribution, as well as the lift, drag, and pitching moment derived therefrom, are displayed in a uniform fashion to delineate the static and dynamic characteristics of each airfoil both in and out of stall. (Author).
Interferometric Investigations of Compressible Dynamic Stall Over a Transiently Pitching Airfoil
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 17
Book Description
The dynamic stall flow field over NACA 0012 airfoil pitching transiently from 0 - 60 deg at a constant rate under compressible flow conditions has been studied using the real-time technique of point diffraction interferometry. This investigation using nonintrusive diagnostics provides a quantitative description of the overall flow field, including the finer details of dynamic stall vortex formation, growth and the concomitant changes in the pressure distribution. Analysis of several hundred interferograms obtained for a range of flow conditions shows that the peak leading edge suction pressure coefficient that stall is nearly constant for a given free stream Mach number at all nondimensional pitch rates. Also, this value is below that seen in steady flow at static stall for the same Mach number, indicating that dynamic effects significantly effect the separation behavior. Further, for a given Mach number, the dynamic stall vortex seems to form rapidly at nearly the same angle of attack for all pitch rates studied.
Publisher:
ISBN:
Category :
Languages : en
Pages : 17
Book Description
The dynamic stall flow field over NACA 0012 airfoil pitching transiently from 0 - 60 deg at a constant rate under compressible flow conditions has been studied using the real-time technique of point diffraction interferometry. This investigation using nonintrusive diagnostics provides a quantitative description of the overall flow field, including the finer details of dynamic stall vortex formation, growth and the concomitant changes in the pressure distribution. Analysis of several hundred interferograms obtained for a range of flow conditions shows that the peak leading edge suction pressure coefficient that stall is nearly constant for a given free stream Mach number at all nondimensional pitch rates. Also, this value is below that seen in steady flow at static stall for the same Mach number, indicating that dynamic effects significantly effect the separation behavior. Further, for a given Mach number, the dynamic stall vortex seems to form rapidly at nearly the same angle of attack for all pitch rates studied.