| Tip Clearance Control Using Plasma Actuators |
MAR 2007 |
73 pages |
| Authors:
Scott C. Morris; Thomas C. Corke; NOTRE DAME UNIV IN DEPT OF AEROSPACE AND MECHANICAL ENGINEERING
|
 | This report documents experimental results from a series of experiments using active flow control to improve the performance and efficiency of turbine tip clearance flows. The flow control was based on plasma actuators. Two experimental facilities were used as part of this research project. The first was a low-speed, large-scale turbine cascade using Pak-B turbine blades. The second was a smaller scale, high-speed cascade with low aspect ratio. The active ... |
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| Research and Development of a Scaled Joined-Wing Flight Vehicle |
APR 2005 |
25 pages |
| Authors:
Afzal Suleman; INSTITUTO SUPERIOR TECNICO LISBON (PORTUGAL) DEPT OF MECHANICAL ENGINEERING
|
| This report results from a contract tasking Instituto Superior Tecnico as follows: The Grantee will investigate the aeroelastic performance of the joined-wing concept. Dr. Suleman and his research team have proposed to investigate the aeroelastic performance of the joined-wing concept by analyzing, designing, manufacturing, and wind tunnel testing aeroelastically scaled models. The first step will include designing a test assembly to conduct aeroelastic flutter and gust response tests. A fairly ... |
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| F/A-18C to E Wing Morphing Study for the Abrupt Wing Stall Program |
JAN 2003 |
31 pages |
| Authors:
Bradford E. Green; James D. Ott; COMBUSTION RESEARCH AND FLOW TECHNOLOGY INC DUBLIN PA
|
| In an effort to determine the impact of various wing parameters on the abrupt wing stall phenomenon encountered by the pre-production F/A-18E, various characteristics of the F/A-18C wing were modified to reflect the design changes incorporated into the F/A-18E wing. The parameters evaluated during this study included thickness, camber, twist, leading-edge radius, leading-edge flap-chord ratio and the addition of a leading-edge snag. The wing parameters were modified independently and then ... |
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| Performance Evaluation of an OH-58A+ With Dimpletape Installed |
AUG 2001 |
136 pages |
| Authors:
Gregg A. Deetman; TENNESSEE UNIV KNOXVILLE
|
| This flight test investigates the performance benefits of a recently developed vortex generator, called Dimpletape(registered), on an OH-58A+ helicopter rotor blade. This product employs the aerodynamic concepts that are used to reduce the drag on a golf ball. The manufacturer claims significant performance benefits with the product applied to airplane wings and propellers; however, no flight-testing has been conducted on commercial helicopter rotor blades. Four different Dimpletape(registered) lengths where flight-tested ... |
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| Propeller Blade Design Thickness and Blockage Issues Due to Source- Induced Factors |
FEB 2001 |
67 pages |
| Authors:
David S. Hunt; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF MECHANICAL ENGINEERING
|
| A propeller lifting-surface design and analysis program is improved upon by implementing enhancements in the source distribution calculation to represent the blade thickness. It is recognized that the present method of setting the source line distribution representing blade thickness (currently based on linearized slender-body theory for an isolated foil section) may introduce significant errors. This is the case for propulsors with a combination of a large thickness/chord ratio (blockage effect) ... |
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| Test Cases for a Clipped Delta Wing with Pitching and Trailing-Edge Control Surface Oscillations |
01 OCT 2000 |
18 pages |
| Authors:
Robet M. Bennett; DNW(DEUTCH-NIEDERLANDISCHER WINDKANAL)-NWB(NIEDERGESCHWINDIGKEITS-WINDCANAL)BRAUNSCHWEIG (GERMANY)
|
| Steady and unsteady measured pressures for a Clipped Delta Wing (CDW) undergoing pitching oscillations and trailing-edge control surface oscillations have been presented in Ref I and 2. From the several hundred compiled data points, 22 static cases, 12 pitching-oscillation cases, and 12 control-surface-oscillation cases have been proposed for Computational Test Cases to illustrate the trends with Mach number, reduced frequency, and angle of attack. The planform for this wing was ... |
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| Methods of Desensitizing Tip Clearance Effects in Turbines |
OCT 2000 |
101 pages |
| Authors:
J. Tallman; B. Lakshminarayana; PENNSYLVANIA STATE UNIV UNIVERSITY PARK CENTER FOR GAS TURBINES AND POWER
|
| This study is an attempt to reduce the effect of the leakage vortex in axial flow turbines. A 3D Navier-Stokes CFD solver with two equation turbulence modeling was used to compute the flow through an axial flow turbine with modified blade tip designs. The three modified blade tip designs each involved adding a chamfer to the tip of the blade, in an attempt to diffuse the leakage flow through the ... |
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| Flexible Composite Wing with Internal Actuation for Roll Maneuver |
Sep 2000 |
11 pages |
| Authors:
N S Khot; J V Zweber; D E Veley; H Oz; F E Eastep; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AIR VEHICLES DIR/STRUCTURES DIV/STRUCTURAL DESIGN AND DEVELOPMENT BRANCH
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| This paper is concerned with designing an optimum composite flexible wing structure to enhance roll maneuver capability at high dynamic pressures using an embedded actuating system without external control surfaces. A minimum weight design, with constraints on strength for three different flight conditions, on the frequency distribution and lift effectiveness was used for this study. The elastic twist and camber is achieved by providing a system of actuating elements distributed ... |
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| Design Aspects of the Elastic Trailing Edge for an Adaptive Wing |
MAY 2000 |
8 pages |
| Authors:
H. P. Monner; D. Sachau; E. Breitbach; GERMAN AEROSPACE CENTER BRAUNSCHWEIG (GERMANY) INST OF STRUCTURAL MECHANICS
|
| According to predictions of market researchers a large growth in numbers of passengers as well as of airfreight volume can be expected for the civil transport aircraft industry. This will lead to an increased competition between the aircraft manufacturers. To stay competitive it will be essential to improve the efficiency of the new aircraft generation. Especially the transonic wings of civil aircraft with their fixed geometry offer a large potential ... |
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| A Process-Based Cost Estimating Tool for Ship Structural Designs |
MAY 96 |
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| Authors:
John M. Barentine; MASSACHUSETTS INST OF TECH CAMBRIDGE
|
 | There is a significant need, and accompanying significant challenge, to concurrently consider performance, cost and production issues from the very beginning of the design process. The greatest obstacle to this approach is the lack of convenient and effective cost and performance models that can be integrated into a seamless design workbench accessible to working engineers. Traditional models and analysis methods frequently do not provide the sensitivity necessary to consider all ... |
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| A Brisk Maneuvering Device for Undersea Vehicles. |
12 FEB 1996 |
13 pages |
| Authors:
Promode R. Bandyopadhyay; DEPARTMENT OF THE NAVY WASHINGTON DC
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| A nautical vehicle for traveling in a fluid environment, the nautical vehicle comprising a body having a dorsal fin mounted thereon. The body comprises a sidewall, a forward nose and a rear propulsor for propelling the vehicle in an axial direction. The dorsal fin is mounted on the sidewall, and includes a dorsal fin surface and camber generating element for generating a camber to provide a sideways thrust on said ... |
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| An Experimental Investigation of a Sting-Mounted Finite Circulation Control Wing |
DEC 95 |
98 pages |
| Authors:
Lorenzo C. Bradley; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
|
| This study investigated the lift, drag and pitching moment performance of a circulation control wing in the AFIT 5-ft wind tunnel. The experimental wing model was a 20 percent thick, 8.5 percent camber, partial elliptical cross-section, single blowing slot, rectangular planform wing. The aspect ratios tested were 3.99, 3.77 and 3.75. The variables in the investigation included the slot blowing rate and model configuration. The model was modified by adding ... |
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| Rearm/Resupply Concept Study for the Light Forces Artillery |
JUN 94 |
66 pages |
| Authors:
CAMBER CORP ARLINGTON NJ
|
| The rearm/resupply concept study for the towed 155mm howitzer was prepared by the Camber Corporation's Mount Arlington, New Jersey office for the Project Manager-Ammunition Logistics (PM-AMMOLOG) lAW SOW Paragraph 3.6. A four month study which examined the requirements of the 155mm towed howitzer rearm/ resupply process from the Ammunition Transfer Point (ATP) to the howitzer's fighting position was conducted. The study included a review of the current logistic system for ... |
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| An Experimental Investigation of a Finite Circulation Control Wing |
DEC 92 |
76 pages |
| Authors:
John M. Tallarovic; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
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| This wind tunnel investigation examined the lift, drag, and pitching moment of a 20% thick, 8.5% camber, partial elliptical cross-section, single blowing slot, rectangular, circulation control wing. The aspect ratios tested were 3.71 and 3.99. Variables included three differently shaped trailing edge Coanda surfaces and steady blowing and pulsed blowing. The test Reynolds number, based on the chord was 500,000. The-angle of attack was varied from minus 6 degrees to ... |
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| The Effects on Aerodynamic Performance of Designing Supersonic Wings for Laminar Flow Control |
30 JAN 91 |
90 pages |
| Authors:
Carl P. Tilmann; WRIGHT LAB WRIGHT-PATTERSON AFB OH
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| A preliminary technique has been developed for the design of wings to be used with supersonic hybrid method laminar flow control systems. This technique has been used to evaluate the effects on aerodynamic performance of designing supersonic wings for laminar flow control. In this design method, a wing is cambered such that it produces and upper-surface streamwise pressure distribution which is favorable for use in a hybrid laminar flow control ... |
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| Chordwise Loading and Camber for Two-Dimensional Thin Sections |
AUG 89 |
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| Authors:
Michael MacKay; DEFENCE RESEARCH ESTABLISHMENT ATLANTIC DARTMOUTH (NOVA SCOTIA)
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| Derivations are given for the calculation of section camberline from a given segmented chordwise load distribution, and for the inverse problem. In both cases, the algorithms are exact within the limits of thin-wing theory. This document is concerned with two-dimensional, thin, lifting sections and gives the derivation of the camberline from a segmented chordwise loading (the design problem) and the calculation of loading from a discretely-defined camberline (the analysis problem). ... |
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| Parametric Blade Study Test Report Rotor Configuration. Number 4 |
NOV 88 |
288 pages |
| Authors:
C. H. Law; Steven L. Puterbaugh; AIR FORCE WRIGHT AERONAUTICAL LABS WRIGHT-PATTERSON AFB OH
|
| The results of an experimental evaluation of one compressor test of a series of design parameter investigations are presented. The purpose of the parametric blade design study was to investigate the effects of specific rotor blade design parameters on the performance of one compressor configuration of current interest with state-of-the-art performance. It was the intent of the program to vary only one design parameter at a time, keeping the other ... |
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| Parametric Blade Study Test Report Rotor Configuration. Number 2 |
NOV 88 |
288 pages |
| Authors:
C. H. Law; Steven L. Puterbaugh; AIR FORCE WRIGHT AERONAUTICAL LABS WRIGHT-PATTERSON AFB OH
|
| The results of an experimental evaluation of one compressor test of a series of design parameter investigations are presented. The purpose of the parametric blade design study was to investigate the effects of specific rotor blade design parameters on the performance of one compressor configuration of current interest with state-of-the-art performance. It was the intent of the program to vary only one design parameter at a time, keeping the other ... |
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| A Study of Flows Over Highly-Swept Wings Designed for Manoeuvre at Supersonic Speeds |
OCT 88 |
43 pages |
| Authors:
P. R. Ashill; J. L. Fulker; M. J. Simmons; ROYAL AEROSPACE ESTABLISHMENT FARNBOROUGH (UNITED KINGDOM)
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| A wind-tunnel investigation into supersonic free-stream flows over two wing-body configurations, having wings of different design, suitable for combat aircraft, is described. Both wings have the same quasi-delta planform of 60 deg inboard leading-edge sweep and the same 4% thickness distribution but have differing camber distributions. Following a description of the design of the wings, the test procedures are discussed and the general features of the flows at conditions close ... |
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| Calculation and Measurement of Transonic Flows over Aerofoils with Novel Rear Sections |
OCT 88 |
16 pages |
| Authors:
P. R. Ashill; ROYAL AEROSPACE ESTABLISHMENT FARNBOROUGH (ENGLAND)
|
| A combined theoretical and experimental investigation in to transonic flows over aerofoils of advanced design is described. The experiments were performed at high subsonic speeds and over a wide range of Reynolds number up to 20 million on a number of aerofoils with rear pressure distributions of differing form and severity. Three families of aerofoils were studied, all of which are of 14% thickness and have a high degree of ... |
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| Aerodynamic Performance of Wings of Arbitrary Planform in Inviscid, Incompressible, Irrotational Flow |
SEP 88 |
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| Authors:
Chris L. Holm; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| This thesis contains discussion, theory and program code for a computational fluid dynamics (CFD) model of a wing of arbitrary planform. The mathematical model assumes incompressible, inviscid, irrotational flow. The program computes forces acting on the wing by modeling the flow with a set of horseshoe vortex elements. It models the flow over an arbitrary wing using two solutions. One solution is the ideal lift, associated with a cambered and ... |
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| Unsteady Flow About Porous Cambered Plates |
JUN 88 |
63 pages |
| Authors:
Paul J. Lindsey; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The current parachute-canopy design methodology is mainly empirical. Under certain conditions, parachutes have been observed to collapse during periods of rapid deceleration, subsequent to the initial inflation of the canopy with a resulting loss of drag and ultimately the payload. Studies began with a two-dimensional model of flow about a rigid, nonporous camber. Even though highly idealized, the purpose of the investigation was not a solution of an immediate practical ... |
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| Theory of Sound Production by Vortex-Airfoil Interaction |
JAN 88 |
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| Authors:
M. S. Howe; BBN LABS INC CAMBRIDGE MA
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| An analysis is made of the sound produced when a field of vorticity is cut by an airfoil in low Mach number flow. A general formula is given for the acoustic pressure when the airfoil is rigid and the chord is acoustically compact. This expresses the radiation in terms of an integral over the region occupied by the vorticity; the integrand contains factors describing the influence of the thickness, twist ... |
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| Unsteady Flow about Cambered Plates |
01 OCT 87 |
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| Authors:
T. Sarpkaya; S. I. Mostafa; P. D. Munz; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| Impulsively-started uniform flow, decelerating at specified rates, about two-dimensional cambered plates with included angles of 120, 180, and 240 degrees has been investigated both theoretically and experimentally. The experiments were conducted in a vertical water tunnel. The forces acting on the cambered plates have determined as a function of the relative displacement of the fluid. The evolution of the vortices was visualized by means of various dyes and polystyrene beads. ... |
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| Composite Grid and Finite-Volume LU (Lower-Upper) Implicit Scheme for Turbine Flow Analysis |
JUN 87 |
|
| Authors:
Yung K. Choo; Seokkwan Yoon; Kestutis C. Civinskas; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH LEWIS RESEARCH CENTER
|
| A composite grid was generated in an attempt to improve grid quality for a typical turbine blade with large camber in terms of mesh control, smoothness, and orthogonality. This grid consists of the C-grid in the immediate vicinity of the blade and the H-grid in the upstream region and in the middle of the blade passage between the C-grids. It provides good boundary layer resolution around the leading-edge region for ... |
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| Numerical Simulation of Unsteady Separated Flows |
JUN 87 |
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| Authors:
Samir I. Mostafa; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| Two unsteady flows dominated by the occurrence of separation are simulated through the use of the discrete vortex model. The first of these is a sinusoidally oscillating flow about a circular cylinder at a Keulegan-Carpenter number of K = 10. The vortex model has been combined with the boundary layer calculations and the positions of the separation and stagnation points, the evolution of the wake, the velocity and pressure distributions, ... |
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| Aircraft with Single Surface Membranous Airfoils. |
26 MAY 1987 |
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| Authors:
Samuel Greenhalgh; DEPARTMENT OF THE NAVY WASHINGTON DC
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| A remotely piloted vehicle is provided with single surface membranous airfoils controllable in flight. The airfoils are selectively deployed from a stowed position on either side within fuselage by spars attached to the leading edges. Pivotal members attached to the root edges of the airfoils are positioned to regulate twist distribution, angle of attack, root camber ratio and root camber distribution. Keywords: Extendable structures. |
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| The Integration of Computational Fluid Dynamics into the Military Aircraft Design Process, |
NOV 1986 |
|
| Authors:
W. R. Marchbank; BRITISH AEROSPACE PLC WARTON (ENGLAND) AERODYNAMICS DEPT
|
| Experience gained at British Aerospace (BAe) has shown that both Computational Fluid Dynamic (CFD) methods and experimental facilities play very important and complimentary roles in the design of modern military aircraft. The combination of theory and experiment gives a very powerful tool that has a significant impact on configuration design, allowing successful first time optimisation of aircraft shape. The main impact of CFD in configuration design is in allowing very ... |
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| Generation of a Composite Grid for Turbine Flows and Consideration of a Numerical Scheme |
NOV 86 |
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| Authors:
Y. Choo; S. Yoon; C. Reno; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH LEWIS RESEARCH CENTER
|
| A composite grid was generated for flows in turbines. It consisted of the C-grid (or O-grid) in the immediate vicinity of the blade and the H-grid in the middle of the blade passage between the C-grids and in the upstream region. This new composite grid provides better smoothness, resolution, orthogonality than any single grid for a typical turbine blade with a large camber and rounded leading and trailing edges. The ... |
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| Variable Camber Tandem Blade Bow for Turbomachines. |
08 JUL 1986 |
|
| Authors:
John G. Stricker; DEPARTMENT OF THE NAVY WASHINGTON DC
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| Multiple flat-plate blade rows of pitch adjustable blades are offset mounted in a manner such that when flat-plate blades in adjacent rows are aligned at a specific pitch setting, respective flat-plate blades of the adjacent rows nearly mate. The offset between the flat-plate blade rows functions to produce unequal pitch angle settings of the blades of adjacent rows which, in turn, function to produce the result that the respective flat-plate ... |
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| Partially Cavitating Flows about Foils |
MAR 86 |
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| Authors:
C. C. Hsu; DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER BETHESDA MD
|
| A practical approach for predicting partially cavitating flow characteristics of foil sections is presented. The method take into account indirectly the viscous flow effects and the interaction between the fully wetted and perturbed cavitating flows. The partially cavitating flow characteristics are found to be sensitive to variations in the angle of attack, camber, thickness, and the thickness distribution. Some comparisons between the calculated and measured cavity lengths are made, and ... |
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| Partially Cavitating Flows about Foils |
MAR 86 |
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| Authors:
C. C. Hsu; DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER BETHESDA MD
|
| There is concern with avoiding problems and reducing the likelihood of propeller-induced hull vibration, noise, and blade erosion on Navy ships. The unsteady surface pressure excitation and local flow instability responsible for these problems are associated with blade sheet cavity geometry and cavity dynamics. Reliable computational tools for the analysis of propeller blade sheet cavitation would be useful for assessments of given propeller/wake/hull arrangements and for guidance of new propeller ... |
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| Hub Effects in Propeller Design and Analysis |
JUL 85 |
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| Authors:
M. H. Wang; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF OCEAN ENGINEERING
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| A numerical model is established for the design of propeller blade shape for a prescribed circulation and a given hub geometry. The vortex lattice approach is adapted for blades and their wakes. The hub is represented by a distribution of dipoles which ends at the hub apex. It is shown that consideration of the hub results in a lower pitch and lower camber at the inner radii. An iterative method ... |
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| Non-Linear Corrections to the Linear Theory for the Prediction of the Cavitating Flow Around Hydrofoils |
JUN 85 |
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| Authors:
S. A. Kinnas; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF OCEAN ENGINEERING
|
| The problem of a partial or supercavitating hydrofoil in linear theory is formulated in terms of integral equations of unknown vortex and cavity source distributions. The general problem is decomposed into one camber, one of thickness, and one of angle of attack. The general solution is given in terms of integrals of known functions over the cavity length for partial or over the chord length for supercavitating hydrofoils. The numerical ... |
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| Variable Camber Tandem Blade Row for Turbomachines. |
19 DEC 1984 |
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| Authors:
John G. Stricker; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| This patent application relates generally to variable pitch, flat-plate blade rows for turbomachinery, and more particularly, to variable pitch, offset multiple flat-plate blade rows for bidirectional thrust or flow devices which effectively provide variable camber blade row configurations. Multiple flat-plate blade rows of pitch adjustable blades are offset mounted in a manner such that when flat-plate blades in adjacent rows are aligned at a specific pitch setting, respective flat-plate blades ... |
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| Cooled Turbine Blade Tip Closure. |
11 DEC 1984 |
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| Authors:
R. L. Horvath; R. W. Harris; DEPARTMENT OF THE AIR FORCE WASHINGTON DC
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| In this patents, an improved high pressure turbine rotor blade and tip cap structure therefore is provided, which comprises, a plurality of metallic layers bonded to the tip end of the blade, each layer having a peripheral shape conforming to the camber of the blade, the layers defining a plurality of radially outwardly opening, serpentine-shaped passageways for passage of coolant fluid through the periphery of the tip end of the ... |
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| Influence of Surface Roughness on Compressor Blades at High Reynolds Number in a Two-Dimensional Cascade |
DEC 84 |
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| Authors:
G. P. Moe; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
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| This is a thesis. A cascade test facility has been established which incorporates sidewall boundary layer control, permitting two-dimensional flow investigation over the center span (about 2/3 the width of the blade) of an airfoil in cascade, and an investigation has been conducted to determine the influence of roughness on the airfoil. Two representative compressor profiles, the NACA 64-A905 and 65-A506, with two inch chords and aspect ratios of one ... |
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| Low-Speed Characteristics of a Circulation Control Airfoil with AFT camber and a Spiral Trailing Edge |
DEC 84 |
41 pages |
| Authors:
J. Abramson; DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER BETHESDA MD AVIATION AND SURFACE EFFECTS DEPT
|
| A circulation control elliptic airfoil section with a 15-percent thickness-to-chord ratio which incorporates a spiral trailing edge was evaluated subsonically to determine its aerodynamic characteristics. The spiral-shaped Coanda surface was previously evaluated with a different leading edge. The airfoil, designated NCCR 1505-7567S, has an uncambered forward half and a cambered aft portion resulting in a 0.005-percent camber for the profile. This particular combination of camber was selected because it was ... |
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| Cavity Shape Characteristics for Supercavitating Hydrofoils |
OCT 84 |
|
| Authors:
S. A. Kinnas; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF OCEAN ENGINEERING
|
| In this work the problem of a supercavitating hydrofoil in linear theory is stated in terms of integral equations of unknown vortex and cavity source distributions. The general problem is composed into the camber, the thickness and the angle of attack problems. For each problem the solution is expressed in terms of integrals of the slope of the lower surface of the hydrofoil weighted by known functions. The numerical scheme ... |
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| Fuel Efficient Propulsor for Motor Boats. |
20 JUL 1984 |
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| Authors:
W. S. Gearhart; DEPARTMENT OF THE NAVY WASHINGTON DC
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| This patent application discloses an improved propulsor for motorboats which includes a plurality of cambered skegs or fins mounted forward of the propeller which are placed in a manner so that a counter-swirl is generated in the fluid in the direction counter to the swirl produced by the propeller rotation . The cambered skegs and the fairing strut are designed to reduce the swirl caused by the propeller in the ... |
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| A Wind Tunnel Investigation to Determine Dominant Forebody Strake Design Characteristics for an F-15 Equipped with Conformal Fuel Tanks |
DEC 1983 |
|
| Authors:
T. A. Duncan; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
|
| A parametric study was made in the AFIT 5-ft wind tunnel of forebody strakes on an F-15C model equipped with conformal fuel tanks. Parameters of interest were strake planform area and strake angle of incidence. Twenty configurations were evaluated for longitudinal and lateral stability at angles of attack from -4 to 46 deg. Lift coefficient, drag coefficient, and pitching moment coefficient (CM) were plotted angle of attack (alpha). Data indicated ... |
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| Investigation of Effects Contributing to Dynamic Stall Using a Momentum- Integral Method |
DEC 1983 |
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| Authors:
J. S. Lawrence; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
|
| Dynamic stall effects are analyzed in this investigation for cases of an inertially static airfoil in a flow field rotating at constant rate (gust response), and an airfoil pitching at constant rate in a steady flow field. The method used is a boundary layer solution of the momentum-integral equation by a modified von Karman-Pohlhausen technique. Previous work using this method to match Kramer's experimental results for gust response is reviewed, ... |
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| The Effect of Trailing Vortices on the Production of Lift on an Airfoil Undergoing a Constant Rate of Change of Angle of Attack |
DEC 1983 |
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| Authors:
K. W. Tupper; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
|
| The purpose of this study was to investigate the effect a trailing vortex wake has on an airfoil undergoing a constant rate of change of angle of attack, alpha, in two-dimensional, incompressible, irrotational flow. Potential flow theory, conformal mapping by the Joukowski transformation, and numerical integration and differentiation techniques were used to develop a computer algorithm to model the problem. Once the program was formulated, it was used to solve ... |
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| A Three Dimensional Inextensible Lifting Membrane Wing-Experimental Results |
25 OCT 83 |
44 pages |
| Authors:
S. Greenhalgh; NAVAL AIR DEVELOPMENT CENTER WARMINSTER PA AIRCRAFT AND CREW SYSTEMS TECHNOLOGY DIRECTORATE
|
| The results of a wind tunnel test program on an inextensible semi span membrane wing are presented. The wing was of triangular planform of 9.8 aspect ratio. The tests were run at a Reynolds number of 600,000. Observations and aerodynamic data were obtained for several wing configurations of camber and washout. The report presents the experimental data with a discussion and interpretation of the results. Originator-supplied keywords include: Aerodynamics, Lifting ... |
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| Aerodynamics of Airfoils Subject to Three-Dimensional Periodic Gusts |
31 AUG 1983 |
|
| Authors:
H. Atassi; NOTRE DAME UNIV IN AERODYNAMICS LAB
|
| A general analysis of periodic three-dimensional vortical disturbances of streaming motions around streamlined and bluff bodies is developed using a unified approach wherein the mathematical problem is reduced to solving a single inhomogeneous wave equation with non-constant coefficients. In the limit of vanishing Mach number, the problem is formulated in terms of an inhomogeneous Fredholm integral equation of the second kind. The analysis is first applied to study the unsteady ... |
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| Measurements of Direct Path and Folded Path Optical Scintillation Path Weightings |
JUN 1983 |
|
| Authors:
Alfred Guy Costantine; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| A theoretical prediction by Dr. Avihu Ze'evi of the relative contribution to the optical scintillation by different points along the path was described by a weight function for direct and exact folded path spherical wave sources. In an effort to verify this prediction a turbulence chamber was built to allow a controlled turbulence source to be moved and measured at different path positions in conjunction with scintillation measurements. The experimental ... |
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| An Experimental/Analytical Investigation into the Performance of a 20- Percent Thick, 8.5-Percent Cambered, Circulation Controlled Airfoil |
DEC 1982 |
|
| Authors:
John K. Harvell; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
|
| This study was conducted to investigate the effect of two tangentially blown slots on the performance of a 20-percent thick, 8.5-percent cambered elliptical airfoil. Lift, drag, and moment coefficients were obtained at a test Reynolds number of 9.5 x 100,000 for secondary slot locations of 73.5 and 83.5 deg. Results show that the use of two tangentially blown slots enables the generation of higher lift coefficients at lower blowing rates. ... |
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| Design of Propeller Ducts to Reduce Cavitation and Vibration |
SEP 1982 |
|
| Authors:
T. R. Goodman; J. P. Breslin; STEVENS INST OF TECH HOBOKEN NJ DAVIDSON LAB
|
| A procedure based on inviscid flow theory is detailed for the design of propeller ducts to reduce specific spatial non-uniform in given nominal ship wakes. The objective is to produce net flows to enclosed propellers which will reduce cavitation and vibratory forces. The process yields peripheral variations of camber and conicity angle which will reduce the amplitude of specific wake harmonics to a maximum extent possible under the arbitrarily imposed ... |
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| Transonic Fan/Compressor Rotor Design Study. Volume II. |
FEB 1982 |
121 pages |
| Authors:
D. E. Parker; M. R. Simonson; GENERAL ELECTRIC CO CINCINNATI OH AIRCRAFT ENGINE BUSINESS GROUP
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| Volumes I through V of this report describes the aerodynamic design of a series of five transonic rotors all parametrically related to a baseline design documented in Technical Report AFAPL-TR-79-2078. Each of the five designs deviate from the baseline, in so far as practical, by a variation of one parameter only. The parametric variations are specified at the rotor tip. This volume describes the aerodynamic design details of the Phase ... |
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| Transonic Fan/Compressor Rotor Design Study. Volume III. |
FEB 1982 |
125 pages |
| Authors:
D. E. Parker; M. R. Simonson; GENERAL ELECTRIC CO CINCINNATI OH AIRCRAFT ENGINE BUSINESS GROUP
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| Volumes I through VI of this report describes the aerodynamic design of a series of five transonic rotors all parametrically related to a baseline design documented in Technical Report AFAPL-TR-79-2078. Each of the five designs deviate from the base line, in so far as practical, by a variation of one parameter only. The parametric variations are specified at the rotor tip. The original hub characteristics were preserved to the maximum ... |
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