| An Experimental Investigation of the Geometric Characteristics of Flapping-Wing Propulsion for a Micro Air Vehicle |
JUN 2003 |
89 pages |
| Authors:
Jason Papadopoulos; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF AERONAUTICS AND ASTRONAUTICS
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 | The geometric characteristics of flapping-wing propulsion are studied experimentally through the use of a force balance and a Micro Air Vehicle (MAV) system. The system used is built to duplicate the propulsion system currently on the flying model at the Naval Postgraduate School (NPS) MAV model. Experiments are carried out in a low speed wind tunnel to determine the effects of mean separation and plunge amplitude on the flapping wing ... |
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| Study of Hydrogen As An Aircraft Fuel |
JUN 2003 |
69 pages |
| Authors:
J. S. Ciaravino; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF AERONAUTICS AND ASTRONAUTICS
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| The conversion to hydrogen as a naval aviation fuel would allow for independence on fuel cost and supply, as hydrogen is globally accessible. The biggest obstacle to using hydrogen is its very low density, a property that even combined with hydrogen's high heat of combustion still results in very large fuel tanks. Liquid hydrogen (LH2) with its higher density would still require a larger volume than kerosene for the aircraft ... |
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| On the Use of Vortex Flows for the Propulsion of Micro-Air and Sea Vehicles |
MAR 2003 |
15 pages |
| Authors:
K. D. Jones; M. F. Platzer; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF AERONAUTICS AND ASTRONAUTICS
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| Recent interest in flapping-wing propulsion, in particular for hovering or low-speed flight of micro air vehicles, has led to a renewed interest in the measurement and prediction of unsteady, vortex-dominated flows. The proposed vehicles typically operate at Reynolds numbers below 20,000, and operate with mildly to fully separated flow throughout the flapping cycle. This paper provides a brief history on the topic, and summarizes research efforts at the Naval Post-graduate ... |
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| Development of Precision Pointing Controllers with and Without Vibration Suppression for the NPS Precision Pointing Hexapod |
DEC 2002 |
116 pages |
| Authors:
Ronald M. Bishop Jr; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF AERONAUTICS AND ASTRONAUTICS
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| Satellite optical payloads demand better vibration control and finer precision pointing than ever before. Fortunately, the Stewart-Gough platform offers the potential of accomplishing both of these simultaneously. Using the Precision Pointing Hexapod at NPS (a Stewart-Gough platform), several controllers for precision pointing, with and without vibration disturbances, were developed. Unlike the traditional means of pointing a hexapod, (i.e. sensing and controlling strut length to orient payload), this research used the ... |
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| Spacecraft Power Beaming and Solar Cell Annealing Using High-Energy Lasers |
DEC 2002 |
94 pages |
| Authors:
Richard C. Luce Jr.; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF AERONAUTICS AND ASTRONAUTICS
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| Satellite lifetime is often limited by degradation of the electrical power subsystem--radiation-damaged solar arrays and failed batteries, Being able to beam power from terrestrial sites could alleviate this limitation, extending the lifetime of billions of dollars of satellite assets, as well as providing additional energy for electric propulsion that can be used for stationkeeping and orbital changes In addition, laboratory research at the Naval Postgraduate School (NPS) has shown the ... |
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| Summary of Research 2001, Department of Aeronautics and Astronautics, Graduate School of Engineering and Applied Sciences |
SEP 2002 |
59 pages |
| Authors:
Max F. Platzer; Raymond P. Shreeve; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF AERONAUTICS AND ASTRONAUTICS
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| This report contains project summaries of the research projects in the Department of Aeronautics and Astronautics A list of recent publications is also included, which consists of conference presentations and publications, books, contributions to books, published journal papers, and technical reports Thesis abstracts of students advised by faculty in the Department are also included. |
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| Fluid Mechanics of Compressible Dynamic Stall Control Using Dynamically Deforming Airfoils |
04 DEC 2001 |
41 pages |
| Authors:
M. S. Chandrasekhara; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF AERONAUTICS AND ASTRONAUTICS
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| This report summarizes the key results from the two components of the study: (1) development of the knowledge and understanding of the fundamental fluid mechanics of the interactions of the unsteady flow occurring under the influence of the time scales of airfoil reduced frequency and dynamic leading edge adaptation at different flow conditions; (2) understanding of the role of the surface flow in compressible dynamic stall onset. For the former, ... |
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| Effect of Reynolds Number on Separation Bubbles on Controlled-Diffusion Compressor Blades in Cascade |
FEB 2001 |
13 pages |
| Authors:
Garth V. Hobson; Denis J. Hensen; David G. Schnorenberg; Darren V. Grove; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF AERONAUTICS AND ASTRONAUTICS
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| A detailed experimental investigation of second- generation, controlled-diffusion, compressor stator blades at an off-design inlet-flow angle was performed in a low-speed cascade wind tunnel primarily using laser- Doppler velocimetry (LDV). The object of the study was to characterize the off-design flowfield and to obtain LDV measurements of the suction surface boundary layer separation which occurred near mid chord. The effect of Reynolds number on the flow separation in the regime ... |
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| Summary of Research 1998, Department of Aeronautics and Astronautics |
AUG 1999 |
66 pages |
| Authors:
Gerald H. Lindsey; Oscar Biblarz; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF AERONAUTICS AND ASTRONAUTICS
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| This report contains summaries of research projects in the Department of Aeronautics and Astronautics. A list of recent publications is also included which consists of conference presentations and publications, books, contributions to books, published journal papers, technical reports, and thesis abstracts. |
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| Summary of Research 1997, Department of Aeronautics and Astronautics |
JAN 1999 |
60 pages |
| Authors:
Gerald H. Lindsey; Oscar Biblarz; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF AERONAUTICS AND ASTRONAUTICS
|
| This report contains summaries of research projects in the Department of Aeronautics and Astronautics. A list of recent publications is also included which consists of conference presentations and publications, books, contributions to books, published journal papers, technical reports, and thesis abstracts. |
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| Summary of Research 1996, Department of Aeronautics and Astronautics |
NOV 1997 |
74 pages |
| Authors:
NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF AERONAUTICS AND ASTRONAUTICS
|
| This report contains summaries of research projects in the Department of Aeronautics and Astronautics. A list of recent publications is also included which consists of conference presentations and publications, books, contributions to books, published journal papers, technical reports, and thesis abstracts. |
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| Design and Development of a Dynamically Deforming Leading Edge Airfoil for Unsteady Flow Control |
OCT 97 |
10 pages |
| Authors:
M. S. Chandrasekhara; L. W. Carr; M. C. Wilder; G. N. Paulson; C. D. Sticht; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF AERONAUTICS AND ASTRONAUTICS
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| A novel approach to unsteady flow separation and dynamic stall control using a dynamically deforming leading edge airfoil is described. The design details of a carbon-fiber composite skin airfoil having a thickness of 0. 002 in. at the leading edge and capable of deforming at 20 Hz in unsteady flow at freestream Mach numbers of up to 0.45, are discussed. Implementation of the scheme at model scales places extraordinary demands ... |
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| A Fundamental Study of Compressibility Effects on Dynamic Stall of Fixed and Adaptive Airfoils |
08 SEP 97 |
46 pages |
| Authors:
M. S. Chandrasekhara; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF AERONAUTICS AND ASTRONAUTICS
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| A three year research effort on 'A Fundamental Study of Compressibility Effects on Dynamic Stall of Fixed and Adaptive Airfoils' was initiated in 1994. The research led to an understanding of: some of the key mechanisms of compressible dynamic stall including when the flow over the airfoil is transonic; the Reynolds number effects which strongly after the detailed flow physics making extension of laboratory results to full-scale conditions extremely challenging, ... |
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| Development of High Speed Interferometry Imaging and Analysis Techniques for Compressible Dynamic Stall |
SEP 97 |
13 pages |
| Authors:
M. S. Chandrasekhara; L. W. Carr; M. C. Wilder; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF AERONAUTICS AND ASTRONAUTICS
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| The development of a high speed, phase locked, real time, point diffraction interferometry system for quantitative imaging of unsteady separated flows is described. The system enables recording of up to 224 interferograms of the dynamic stall flow over an oscillating airfoil using a drum camera at rates of up to 40 KHz, controlled by custom designed electronic interlocking circuitry. Several thousand interferograms of the flow have been obtained using this ... |
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| Active Vibration Control of Flexible Structures Using the Modular Control Patch (MCP) |
MAR 97 |
120 pages |
| Authors:
Steven P. Schmidt; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF AERONAUTICS AND ASTRONAUTICS
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| Active vibration control has been increasingly used as a solution for spacecraft structures to achieve the degree of vibration suppression required for precision pointing accuracy that is not easily achieved with passive damping. This thesis examines the effectiveness and suitability of the Modular Control Patch (MCP) to achieve active vibration control on flexible structures. The MCP was developed by TRW for the United States Air Force and uses a digital ... |
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| LDV Measurements in the Endwall Region of an Annular Turbine Cascade Through an Aerodynamic Window |
1997 |
9 pages |
| Authors:
G. V. Hobson; W. H. Donovan; J. D. Spitz; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF AERONAUTICS AND ASTRONAUTICS
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| Laser-Doppler velocimetry measurements through a one millimeter hole in the casing of an annular turbine cascade were performed in the endwall region downstream of the blade row. Complementary three-hole pressure probe measurements were also taken downstream of the nozzle blades, as well as blade surface pressure measurements. The object of this study was to devise methods for the measurement close to an endwall and to overcome the problems associated with ... |
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| Compressibility Effects on and Control of Dynamic Stall of Oscillating Airfoil |
23 DEC 94 |
52 pages |
| Authors:
M. S. Chandrasekhara; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF AERONAUTICS AND ASTRONAUTICS
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| A three year effort to study the 'Compressibility Effects on the Control of Dynamic Stall of Oscillating Airfoils' was funded by ARO in 1990. A fourth year extension was granted for the project. As part of this research, a new real-time interferometry system known as Point Diffraction Interometry (PDl) was developed. Several new and exciting details of the dynamic stall flow over an oscillating airfoil such as formation of multiple ... |
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| Laser Anemometry and Viscous Computation of the Flow Through an Annular Turbine Cascade |
MAR 94 |
85 pages |
| Authors:
Joseph D. Spitz; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF AERONAUTICS AND ASTRONAUTICS
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| An annular turbine cascade, designed for laser-Doppler velocimetry , was further modified to provide additional laser and pressure probe access. The purpose of the research was to devise laser anemometry measurement techniques in a confined annulus and improve the ability to compare numerical predictions with experimental results. Flowfield computations were completed using a viscous flow solver, with the numerical exit plane coincident with experimental measurement location. A data reduction program ... |
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| Velocity and Vorticity Distributions Over an Oscillating Airfoil Under Compressible Dynamic Stall |
JUN 1993 |
4 pages |
| Authors:
M. S. Chandrasekhara; S. Ahmed; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF AERONAUTICS AND ASTRONAUTICS
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| The velocity and vorticity fields around an oscillating airfoil in compressible dynamic stall are reported. Phase averaged, two component laser velocimetry data were obtained at a freestream Mach number of 0.3 and a reduced frequency of 0.05. This is the first set of velocity data available at a high Reynolds number (540,000) under compressible flow conditions and it serves as a good database for development and validation of computer codes. ... |
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| LDV Measurements in Dynamically Separated Flows |
1993 |
10 pages |
| Authors:
M. S. Chandrasekhara; R. D. VanDyken; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF AERONAUTICS AND ASTRONAUTICS
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| Two component, phase averaged mean velocity data have been obtained with an LDV system, on the upper surface, near the leading edge of an oscillating airfoil undergoing compressible dynamic stall. In particular, the effect of oscillation amplitude has been studied. The results show that at an oscillation amplitude of 10 degrees, a separation bubble forms, that eventually bursts on the upstroke, well beyond the static stall angle. At 2 degrees ... |
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