An Experimental Study of Dynamic Stall on Advanced Airfoil Section. Volume 2: Pressure and Force Data

An Experimental Study of Dynamic Stall on Advanced Airfoil Section. Volume 2: Pressure and Force Data PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 662

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An Experimental Study of Dynamic Stall on Advanced Airfoil Section. Volume 2: Pressure and Force Data

An Experimental Study of Dynamic Stall on Advanced Airfoil Section. Volume 2: Pressure and Force Data PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 662

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Book Description


An Experimental Study of Dynamic Stall on Advanced Airfoil Sections. Volume 2. Pressure and Force Data

An Experimental Study of Dynamic Stall on Advanced Airfoil Sections. Volume 2. Pressure and Force Data PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 646

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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).

An Experimental Study of Dynamic Stall on Advanced Airfoil Sections. Volume 1: Summary of the Experiment

An Experimental Study of Dynamic Stall on Advanced Airfoil Sections. Volume 1: Summary of the Experiment PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 108

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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 Study of Dynamic Stall on Advanced Airfoil Sections

An Experimental Study of Dynamic Stall on Advanced Airfoil Sections PDF Author: K. W. McAlister
Publisher:
ISBN:
Category :
Languages : en
Pages : 639

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A Study of Dynamic Stall Vortex Development Using Two-Dimensional Data from the AFDD Oscillating Wing Experiment

A Study of Dynamic Stall Vortex Development Using Two-Dimensional Data from the AFDD Oscillating Wing Experiment PDF Author: Myung J. Rhee
Publisher:
ISBN:
Category : Aerodynamic load
Languages : en
Pages : 112

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Book Description
The purpose of this study is to examine the previously unpublished instantaneous pressure data of the Aeroflightdynamics Directorate Two-Dimensional (2D) and Three-Dimensional (3D) Oscillating Wing Experiment to better understand the process of dynamic stall vortex development on the NACA 0015 airfoil. This report presents representative 2D instantaneous pressure data for the upper and lower surfaces of the airfoil at various chordwise locations obtained at specific angles of attack during upstroke and downstroke cycles. Furthermore, the report contains a complete set of plots of instantaneous pressure distributions for the upper surface for all the 2D data sets obtained in the experiment. First, the lift, drag and pitching moment data of various testing conditions are reviewed and analyzed to classify the data both with and without a boundary layer trip into "no stall," "moderate stall," and "deep stall" data. Next, instantaneous pressure distributions on the upper surface of the airfoil are examined for the study of vortex development. The lift and pitching moment data are analyzed to document the dynamic overshoot which delays the development of the stall on the airfoil. Next, the range of angles of attack are selected where the lift and pitching moment data shows significant changes from unsteady flow behavior daring oscillation cycles. Furthermore, based on the unsteady flow characteristics found in each classification of dynamic stall, analysis is continued to identify the conditions where the reduced frequency clearly affects the unsteady flow behavior of the airfoil during the oscillation. This can result in a change of the dynamic stall classification of the airfoil response under various unsteady flow conditions. These conditions are discussed in detail in the comparative studies.

Airfoil Dynamic Stall and Rotorcraft Maneuverability

Airfoil Dynamic Stall and Rotorcraft Maneuverability PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 62

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Book Description
The loading of an airfoil during dynamic stall is examined in terms of the augmented lift and the associated penalties in pitching moment and drag. It is shown that once stall occurs and a leading-edge vortex is shed from the airfoil there is a unique relationship between the augmented lift, the negative pitching moment, and the increase in drag. This relationship, referred to here as the dynamic stall function, shows limited sensitivity to effects such as the airfoil section profile and Mach number, and appears to be independent of such parameters as Reynolds number, reduced frequency, and blade sweep. For single-element airfoils there is little that can be done to improve rotorcraft maneuverability except to provide good static clmax characteristics and the chord or blade number that is required to provide the necessary rotor thrust. However, multi-element airfoils or airfoils with variable geometry features can provide augmented lift in some cases that exceeds that available from a single-element airfoil. The dynamic stall function is shown to be a useful tool for the evaluation of both measured and calculated dynamic stall characteristics of singleelement, multi-element, and variable geometry airfoils.

Unsteady Aerodynamics

Unsteady Aerodynamics PDF Author: Grigorios Dimitriadis
Publisher: John Wiley & Sons
ISBN: 1119762553
Category : Technology & Engineering
Languages : en
Pages : 581

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Book Description
Unsteady Aerodynamics A comprehensive overview of unsteady aerodynamics and its applications The study of unsteady aerodynamics goes back a century and has only become more significant as aircraft become increasingly sophisticated, fly faster, and their structures are lighter and more flexible. Progress in the understanding of flow physics, computing power and techniques, and modelling technologies has led to corresponding progress in unsteady aerodynamics, with a wide range of methods currently used to predict the performance of engineering structures under unsteady conditions. Unsteady Aerodynamics offers a comprehensive and systematic overview of the application of potential and vortex methods to the subject. Beginning with an introduction to the fundamentals of unsteady flow, it then discusses the modelling of attached and separated, incompressible and compressible flows around two-dimensional and three-dimensional bodies. The result is an essential resource for design and simulation in aerospace engineering. Unsteady Aerodynamics readers will also find: MATLAB examples and exercises throughout, with codes and solutions on an accompanying website Detailed discussion of most classes of unsteady phenomena, including flapping flight, transonic flow, dynamic stall, flow around bluff bodies and more Validation of theoretical and numerical predictions using comparisons to experimental data from the literature Unsteady Aerodynamics is ideal for researchers, engineers, and advanced students in aerospace engineering.

Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports PDF Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 704

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An Experimental Study of Dynamic Stall on Advanced Airfoil Sections

An Experimental Study of Dynamic Stall on Advanced Airfoil Sections PDF Author:
Publisher:
ISBN:
Category : Stalling (Aerodynamics)
Languages : en
Pages :

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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. 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 NASA 0012 profile. However, the parameters of the unsteady motion appear to be more important than airfoil shape in determining the dynamic-stall airloads.

Recent Advances in Aerospace Engineering

Recent Advances in Aerospace Engineering PDF Author: Sanjay Singh
Publisher: Springer Nature
ISBN: 9819713064
Category :
Languages : en
Pages : 605

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Book Description