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Numerical Simulation And Comparison Of Symmetrical Supercritical Airfoils For The Near Tip Region Of A Helicopter In Forward Flight
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Book Synopsis Numerical Simulation and Comparison of Symmetrical/supercritical Airfoils for the Near Tip Region of a Helicopter in Forward Flight by : F. F. Badavi
Download or read book Numerical Simulation and Comparison of Symmetrical/supercritical Airfoils for the Near Tip Region of a Helicopter in Forward Flight written by F. F. Badavi and published by . This book was released on 1989 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781722673284 Total Pages :54 pages Book Rating :4.6/5 (732 download)
Book Synopsis Numerical Simulation and Comparison of Symmetrical/Supercritical Airfoils for the Near Tip Region of a Helicopter in Forward Flight by : National Aeronautics and Space Administration (NASA)
Download or read book Numerical Simulation and Comparison of Symmetrical/Supercritical Airfoils for the Near Tip Region of a Helicopter in Forward Flight written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-10 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerodynamic loads on a multi-bladed helicopter rotor in forward flight at transonic tip conditions are calculated. The unsteady, three-dimensional, time-accurate compressible Reynolds-averaged thin layer Navier-Stokes equations are solved in a rotating coordinate system on a body-conformed, curvilinear grid of C-H topology. Detailed boundary layer and global numerical comparisons of NACA-0012 symmetrical and CAST7-158 supercritical airfoils are made under identical forward flight conditions. The rotor wake effects are modeled by applying a correction to the geometric angle of attack of the blade. This correction is obtained by computing the local induced downwash velocity with a free wake analysis program. The calculations are performed on the Numerical Aerodynamic Simulation Cray 2 and the VPS32 (a derivative of a Cyber 205 at the Langley Research Center) for a model helicopter rotor in forward flight. Badavi, F. F. Unspecified Center...
Book Synopsis Comparison of Flight-measured Helicopter Rotor-blade Chordwise Pressure Distributions with Static Two-dimensional Airfoil Characteristics by : James Scheiman
Download or read book Comparison of Flight-measured Helicopter Rotor-blade Chordwise Pressure Distributions with Static Two-dimensional Airfoil Characteristics written by James Scheiman and published by . This book was released on 1967 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Design and Analytical Study of a Rotor Airfoil by : L. U. Dadone
Download or read book Design and Analytical Study of a Rotor Airfoil written by L. U. Dadone and published by . This book was released on 1978 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Some Recent Advances in Computational Aerodynamics for Helicopter Applications by : W. J. McCroskey
Download or read book Some Recent Advances in Computational Aerodynamics for Helicopter Applications written by W. J. McCroskey and published by . This book was released on 1985 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Wind Tunnel Evaluation of a Model Helicopter Main-Rotor Blade With Slotted Airfoils at the Tip by :
Download or read book Wind Tunnel Evaluation of a Model Helicopter Main-Rotor Blade With Slotted Airfoils at the Tip written by and published by . This book was released on 2001 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: Data for rotors using unconventional airfoils are of interest to permit an evaluation of this technology's capability to meet the U.S. Army's need for increased helicopter mission effectiveness and improved safety and survivability. Thus, an experimental investigation was conducted in the Langley Transonic Dynamics Tunnel (TDT) to evaluate the effect of using slotted airfoils in the rotor blade tip region (85 to 100 percent radius) on rotor aerodynamic performance and loads. Four rotor configurations were tested in forward flight at advance ratios from 0.15 to 0.45 and in hover in-ground effect. The hover tip Mach number was 0.627, which is representative of a design point of 4000-ft geometric altitude and a temperature of 95 degrees F. The baseline rotor configuration had a conventional single element airfoil in the tip region. A second rotor configuration had a forward-slotted airfoil with a -6 degrees slat, a third configuration had a forward-slotted airfoil with a -10 degrees slat, and a fourth configuration had an aft-slotted airfoil with a 3 degrees flap (trailing edge down). The results of this investigation indicate that the -6 degrees slat configuration offers some performance and loads benefits over the other three configurations.
Book Synopsis Considerations of Methods of Improving Helicopter Efficiency by : Richard C. Dingeldein
Download or read book Considerations of Methods of Improving Helicopter Efficiency written by Richard C. Dingeldein and published by . This book was released on 1961 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1989 with total page 984 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Theoretical Analysis of Aerodynamic Characteristics of Two Helicopter Rotor Airfoils by :
Download or read book Theoretical Analysis of Aerodynamic Characteristics of Two Helicopter Rotor Airfoils written by and published by . This book was released on 1978 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Aerodynamic Characteristics of an 11-percent-thick Symmetrical Supercritical Airfoil at Mach Numbers Between 0.30 and 0.85 by :
Download or read book Aerodynamic Characteristics of an 11-percent-thick Symmetrical Supercritical Airfoil at Mach Numbers Between 0.30 and 0.85 written by and published by . This book was released on 1969 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Effect on Helicopter Performance of Modifications in Profile-drag Characteristics of Rotor-blade Airfoil Sections by : F. B. Gustafson
Download or read book Effect on Helicopter Performance of Modifications in Profile-drag Characteristics of Rotor-blade Airfoil Sections written by F. B. Gustafson and published by . This book was released on 1944 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: Summary: Performance calculations are presented for a typical helicopter rotor in which three types of airfoil section were successively used. The types represented are the rough conventional, the smooth conventional, and the laminar-flow or low-drag sections as developed for helicopter use. The performance items covered are rotor thrust for fixed power in hovering, range and endurance at cruising speed, and power required at a relatively high forward speed. Contours showing the conditions of operation encountered by the blade section and weighting curves showing the relative importance of the various section angles of attack for specified flight conditions are included as an aid in the interpretation of the results. The calculations indicated that the use of a smooth conventional section will result in marked performance gains throughout the flight range. Definite, though smaller, additional gains in take-off weight and in range and endurance may be realized by the use of a low-drag section. At high forward speeds or at moderate forward speeds and high loadings, however, losses are indicated for the low-drag sections in contrast with the smooth conventional sections. It is demonstrated that, if these losses are to be avoided, the low-drag sections must be designed to avoid the extreme rise in drag coefficient at the higher angles of attack which is characteristic of the low-drag sections now available for use in helicopters.
Book Synopsis Special Course on Inverse Methods for Airfoil Design for Aeronautical and Turbomachinery Applications by :
Download or read book Special Course on Inverse Methods for Airfoil Design for Aeronautical and Turbomachinery Applications written by and published by . This book was released on 1990 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This lecture series is devoted to major aspects of aerofoil design both for aeronautical and turbomachine application. These include: (1) optimisation of target pressure and velocity distribution. Both direct optimisation resulting from an inverse boundary layer calculation and an iterative optimisation of the loses are presented. (2) aerofoil design by means of inverse methods. This ranges from simple parametric definitions of two- dimensional cross sections to a detailed numerical definition of three dimensional shapes. blade or airfoil designs are normally made in two steps, and the lectures are accordingly grouped into two parts. First, optimisation of target pressure and velocity distributions are discussed taking into account the required performance and the lost mechanisms in the boundary layer. Both direct optimisation resulting from an inverse boundary layer calculation, and an iterative optimisation by minimisation of the losses are presented. It is clear from both procedures that inclusion of off-design operation is one of the greatest difficulties involved in blade or airfoil operation. The second part gives an overview of the numerous inverse blade design methods that have been developed both for turbomachinery and aeronautical applications. This ranges from simple parameter definitions of two-dimensional cross-sections to the full three-dimensional definition of wings and blade channels."--DTIC.
Book Synopsis Numerical Study of the Unsteady Aerodynamics of Helicopter Rotor Aerofoils by :
Download or read book Numerical Study of the Unsteady Aerodynamics of Helicopter Rotor Aerofoils written by and published by . This book was released on 1903 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A two-dimensional model of the aerodynamics of rotor blades in forward flight is proposed in which the motion of the blade is represented by periodical variations of the freestrearn velocity and incidence. A novel implicit methodology for the solution of the compressible Reynolds averaged Navier-Stokes equations and a twoequation model of turbulence is developed. The spatial discretisation is based upon Osher's approximate Riernann solver, while time integration is performed using a Newton-Krylov method. The method is employed to calculate the steady transonic aerodynamics of two supercritical aerofoils and the unsteady aerodynamics of pitching aerofoils. Comparison with experiment and independent calculations for these test cases is satisfactory. Further calculations are performed for the self-excited periodic flow around a biconvex aerofoil. Comparison of quasi-steady and unsteady calculations suggests that the flow instability responsible for the self-excited flow is due to the presence of a shock induced separation bubble in the corresponding steady flow. Finally the method is used to predict the aerodynamics of aerofoils performing inplane and combined inplane-pitching motions. Results show that quasi-steady aerodynamic models are unsuitable at conditions representative of high-speed forward flight. For shock free flows, the unsteady effects of freestrearn oscillations can be represented by a simple phase lag. For transonic flows the influence of unsteadiness on shock wave dynamics is shown to be complex. Calculations for indicial motion show that the unsteady behaviour of the flow is related to the finite time taken by disturbance waves to travel to the shock wave from the leading and trailing edges of the aerofoil.
Book Synopsis Basic Helicopter Aerodynamics by : John M. Seddon
Download or read book Basic Helicopter Aerodynamics written by John M. Seddon and published by John Wiley & Sons. This book was released on 2011-08-22 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: Basic Helicopter Aerodynamics is widely appreciated as an easily accessible, rounded introduction to the first principles of the aerodynamics of helicopter flight. Simon Newman has brought this third edition completely up to date with a full new set of illustrations and imagery. An accompanying website www.wiley.com/go/seddon contains all the calculation files used in the book, problems, solutions, PPT slides and supporting MATLAB® code. Simon Newman addresses the unique considerations applicable to rotor UAVs and MAVs, and coverage of blade dynamics is expanded to include both flapping, lagging and ground resonance. New material is included on blade tip design, flow characteristics surrounding the rotor in forward flight, tail rotors, brown-out, blade sailing and shipborne operations. Concentrating on the well-known Sikorsky configuration of single main rotor with tail rotor, early chapters deal with the aerodynamics of the rotor in hover, vertical flight, forward flight and climb. Analysis of these motions is developed to the stage of obtaining the principal results for thrust, power and associated quantities. Later chapters turn to the characteristics of the overall helicopter, its performance, stability and control, and the important field of aerodynamic research is discussed, with some reference also to aerodynamic design practice. This introductory level treatment to the aerodynamics of helicopter flight will appeal to aircraft design engineers and undergraduate and graduate students in aircraft design, as well as practising engineers looking for an introduction to or refresher course on the subject.
Download or read book Proceedings written by and published by . This book was released on 1975 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Comparison of Computational and Experimental Results for a Supercritical Airfoil by : Melissa B. Rivers
Download or read book Comparison of Computational and Experimental Results for a Supercritical Airfoil written by Melissa B. Rivers and published by . This book was released on 1994 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: A computational investigation was performed to study the flow over a supercritical airfoil model. Solutions were obtained for steady-state transonic flow conditions using a thin-layer Navier-Stokes flow solver. The results from this computational study were compared with time-averaged experimental data obtained over a wide Reynolds number range at transonic speeds in the Langley 0.3-Meter Transonic Cryogenic Tunnel. Comparisons were made at a nominal Mach number of 0.72 and at Reynolds numbers ranging from 6 X 10(6) to 35 X 10(6).
Book Synopsis Wind Tunnel Evaluation of a Model Helicopter Main-rotor Blade with Slotted Airfoils at the Tip by : United States. National Aeronautics and Space Administration
Download or read book Wind Tunnel Evaluation of a Model Helicopter Main-rotor Blade with Slotted Airfoils at the Tip written by United States. National Aeronautics and Space Administration and published by . This book was released on 2001 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: Data for rotors using unconventional airfoils are of interest to permit an evaluation of this technology's capability to meet the U.S. Army's need for increased helicopter mission effectiveness and improved safety and survivability. Thus, an experimental investigation was conducted in the Langley Transonic Dynamics Tunnel (TDT) to evaluate the effect of using slotted airfoils in the rotor blade tip region (85 to 100 percent radius) on rotor aerodynamic performance and loads. Four rotor configurations were tested in forward flight at advance ratios from 0.15 to 0.45 and in hover in-ground effect. The hover tip Mach number was 0.627, which is representative of a design point of 4000-ft geometric altitude and a temperature of 95 F. The baseline rotor configuration had a conventional single-element airfoil in the tip region.
