| F-16 Ventral Fin Buffet Alleviation Using Piezoelectric Actuators |
Sep-2009 |
122 pages |
| Authors:
Joseph S Browning; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH DEPT OF AERONAUTICS AND ASTRONAUTICS
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 | Buffet-induced vibrations can have a disastrous impact on aircraft structures. Early attempts at combating buffet vibrations included passive methods such as structural enhancements and leading edge fences. Active methods have shown greater promise, including active airflow control, control surface modulation, and active structural control using piezoelectric actuators. Surface mounted piezoelectric actuators impart directional strain reducing the negative effects associated with harmful vibration. The Block-15 F-16 ventral fin represents an aircraft ... |
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| Cruise Report for the April 2009 Gulf of Alaska Line- Transect Survey (GOALS) in the Navy Training Exercise Area |
Jun-2009 |
39 pages |
| Authors:
John Calambokidis; Brenda K Rone; Annie B Douglas; Phil Clapham; Anthony Martinez; Laura J Morse; NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION MIAMI FL SOUTHEAST FISHERIES SCIENCE CENTER
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| The United States Navy, which maintains a maritime training area in the central Gulf of Alaska (GoA), funded a vessel-based line-transect survey during April 2009 to determine marine mammal species distribution and abundance in the training area. The survey cruise employed multiple observation techniques, including visual and passive acoustic observations, as well as photographic identifications. Results of the survey are presented in this document. During the survey cruise, fin whales ... |
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| Investigating the Relationship Between Fin and Blue Whale Locations, Zooplankton Concentrations and Hydrothermal Venting on the Juan de Fuca Ridge |
Jan-2008 |
10 pages |
| Authors:
William S Wilcock; Richard E Thomson; WASHINGTON UNIV SEATTLE SCHOOL OF OCEANOGRAPHY
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| We are investigating the potential correlation between whale tracks, enhanced zooplankton concentrations and hydrothermal vents above the Juan de Fuca Ridge with the long-term goal of understanding such correlations in terms of the influences of globally distributed hydrothermal plumes on the trophic ecology of the deep ocean. We are conducting a retrospective study using existing seismic and bio-acoustical data sets from the Juan de Fuca Ridge with the following four ... |
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| Orcas in Puget Sound |
JAN 2007 |
31 pages |
| Authors:
Birgit Kriete; CORPS OF ENGINEERS SEATTLE WA SEATTLE DISTRICT
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| Ecologically, economically and recreationally, southern resident and transient killer whales have become greatly important to the nearshore environment of Puget Sound. Economically, whale watching in the San Juan Islands alone has become a $10 million industry in the last few years. The stock of southern resident killer whales (SRKW) in the eastern North Pacific declined by almost 20% in a five-year period to fewer than 80 individuals in 2001. These ... |
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| Application of Computational Fluid Dynamics to a Preliminary Extended Area Protection System (EAPS) Projectile |
SEP 2006 |
30 pages |
| Authors:
Karen Heavey; Jubaraj Sahu; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| Computational fluid dynamics approaches were used to compute the flow fields and aerodynamic forces and moments of a slender-body finned projectile. Steady-state numerical results have been obtained for a series of cases, with Mach numbers ranging from 1.5 to 5.0 and at angles of attack from 0 deg to 5 deg. Full three-dimensional computations were performed using a cubic k-epsilon turbulence model. In general, the computed aerodynamic coefficients compared well ... |
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| Store Separation Simulation of the Penguin Missile from Helicopters |
May-2006 |
44 pages |
| Authors:
Daniel J Lesieutre; Marnix F Dillenius; Jens A Gjestvang; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
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| Under contract to Kongsberg Defence & Aerospace (KDA), Nielsen Engineering & Research (NEAR) combined and extended store separation simulation code NEAR STRLNCH and aerodynamic prediction code NEAR MISDL to simulate and analyze launch and separation of the KDA Penguin missile from a helicopter. One of the objectives was to enable the running of many cases in relatively short time on readily available computer platforms. The resulting MISDL/KDA code was validated ... |
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| Novel High-Performance Grid Fins for Missile Control at High Speeds: Preliminary Numerical and Experimental Investigations |
May-2006 |
53 pages |
| Authors:
Erich Schuelein; Daniel Guyot; DEUTSCHES ZENTRUM FUR LUFT-UND RAUMFAHRT (DLR) GOETTINGEN (GERMANY) INSTITUT FUER AERODYNAMIK UND STROEMUNGSTECHNIK
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| This work investigates locally swept grid fins (lattice wings) in terms of their performance over conventional lattice wings at high speeds. The study includes numerical simulations of the supersonic flow around conventional and locally swept planar and lattice wings of infinite span as well as direct force measurements at corresponding realistic finite span models in the Ludwieg Tube Facility at DLR (RWG). The investigations were performed at free-stream Mach numbers ... |
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| Aerodynamics of Wraparound Fins in Supersonic Flow |
APR 2006 |
62 pages |
| Authors:
Brett L. Wilks; ARMY AVIATION AND MISSILE COMMAND REDSTONE ARSENAL AL SYSTEM SIMULATION AND DEVELOPMENT DIRECTORATE
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| Existing supersonic fin theory has been modified to compute the pressure distribution over Wraparound Fin (WAF). Evvard's theory has been used to calculate the pressure loading due to Angle-of-Attack (AoA) on a WAF by including fin curvature as a variable in the definition of zones of influence. Evvard's theory uses the intersections of the fin surface and the Mach cones originating from the leading edge discontinuities to split the fin ... |
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| Investigation of the Effects of Target Feature Variations on Ballistic Missile RCS |
MAR 2006 |
112 pages |
| Authors:
Sang H. Lee; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| Uncertainties about certain features of target geometries can result in a loss of confidence in target signature assessment. This thesis describes the development of a general "rule-of-thumb" to determine how the radar signature of a target varies as a function of the target's specific features. The targets of interest in this study are fictitious ballistic missiles. Four target features of these missiles are investigated: fin size, nose cone shape, panel ... |
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| RTO WG 10: CFD Validation for Shock Wave Turbulent Boundary Layer Interactions |
01 JAN 2006 |
31 pages |
| Authors:
Doyle Knight; Hong Yan; Argyris Panaras; Alexander Zheltovodov; RUTGERS - THE STATE UNIV PISCATAWAY NJ DEPT OF MECHANICAL AND AEROSPACE ENGINEERING
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| NATO RTO Working Group 10 was established in December 1998 to examine the technologies of plug nozzles, scramjet propulsion and Computational Fluid Dynamics (CFD) for design of propelled hypersonic vehicles. The CFD subgroup evaluated six topics: boundary layer transition and instability, real gas flow, laminar viscous-inviscid interactions, shock-shock interactions, shock wave turbulent boundary layer interaction (SWTGBLI) and base flows with and without plume interaction. This paper presents a summary of ... |
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| Cruise Report - R/V Endeavor (Oct 4-8, 2005). Test of ARL-Penn State/APL-UW Towed CTD Chain |
31 DEC 2005 |
9 pages |
| Authors:
Kevin Williams; Kyle Becker; Frank Henyey; Ren-Chieh Lien; Dajun Tang; PENNSYLVANIA STATE UNIV UNIVERSITY PARK APPLIED RESEARCH LAB
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| This report describes a test to evaluate performance of a towed CTD chain manufactured by ADM Elektronik (Germany) and owned jointly by ARL/Penn State and APL/University of Washington. The test was conducted in the vicinity of 71.2 E, 40.2 N on the continental shelf of the US, in preparation for the SW06 experiment, which calls for the chain to be towed repeatedly through nonlinear internal wave (NLIW) packets. As configured ... |
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| Correlation of VERES Predictions for Multihull Ship Motions |
SEP 2005 |
32 pages |
| Authors:
John F. O'Dea; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD
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| A correlation effort was completed to determine if the VEssel RESponse (VERES) program was suitable for predicting the motions of high-speed multi-hull vessels. Head and bow wave heave and pitch responses correlated reasonably well with available model test result, with VERES tending to over-predict response magnitudes as speed is increased. A limited study of the use of fins for motion control demonstrated the possibility of a large reduction in motion ... |
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| CTH Analyses of Fragment Penetration Through Heat Sink Fins |
JUN 2005 |
29 pages |
| Authors:
Anand Prakash; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| Vulnerability/lethality analysis codes (e.g., MUVES-S2) generally use the FATEPEN (fast air target encounter penetration) and THOR penetration models to determine damage produced by impacts of fragments. For simple impact scenarios, e.g., normal fragment impact on monolithic plates, these two models give reasonable predictions for penetration, perforation, and residual velocity. It is, however, not clear how realistic the predictions of these models are for more complicated scenarios. This report presents more ... |
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| Numerical Analysis of Laminar Natural Convection Heat Transfer Around Two Vertical Fins by a Spectral Finite Difference Method |
14 APR 2005 |
9 pages |
| Authors:
HaeHwan Song; Yoshihiro Mochimaru; TOKYO INST OF TECHNOLOGY (JAPAN)
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| A numerical solution is presented for the natural convection heat transfer from two vertical fins using a spectral finite difference method. Virtual distant boundary conditions for two bodies that are compatible with plume behavior and with an overall continuity condition are introduced. A boundary-fitted coordinate system is formed. Streamlines, isotherms, mean Nusselt numbers and drag and lift coefficients are presented for a variety of dimensionless parameters such as a Grashof ... |
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| Submarine Countermeasure and Launch Assembly |
04 APR 2005 |
16 pages |
| Authors:
Robert F. Doleski; DEPARTMENT OF THE NAVY WASHINGTON DC
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| This patent application discloses a submarine countermeasure vehicle and launch assembly. The vehicle includes a forward end portion, an aft end portion provided with a propeller and fins, a hull portion extending between the forward and aft portions, the hull portion being circular in cross-section, and a thrust ring mounted on the fins and around the propeller, the thrust ring forming a convex configuration. The launch assembly includes a launch ... |
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| A Redesigned Tail Rotor for Improvement of CH-53E High-Altitude Performance |
MAR 2005 |
135 pages |
| Authors:
James A. Pritchard; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| The Global War on Terror with specific emphasis on the recent military operation in Afghanistan has shown the invaluable contribution that heavy lift helicopters bring to the combatant commander. However, the flight range, altitudes and lift capability required to operate effectively in such an austere environment are pushing the limits of these helicopters. In an attempt to increase the operational capability of the CH-53E, this study will investigate methods for ... |
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| Control Authority of a Projectile Equipped With an Internal Unbalanced Part |
NOV 2004 |
60 pages |
| Authors:
Geoffrey W. Frost; Mark F. Costello; OREGON STATE UNIV CORVALLIS
|
| A key technical challenge for smart weapon developers is design of appropriate control mechanisms that provide sufficient control authority to enable correction of typical trajectory errors while not excessively burdening the overall weapon design. The work reported here considers a rotating mass unbalance control mechanism created by radial orientation of an internal part. To investigate the potential of this control mechanism, a seven degree-of- freedom flight dynamic model of a ... |
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| Multi-Lobed Buoyant Launch Capsule |
20 OCT 2004 |
16 pages |
| Authors:
Stephen J. Plunkett; DEPARTMENT OF THE NAVY WASHINGTON DC
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| A launch capsule assembly having a buoyant main body for a payload of a missile or other unmanned vehicle. The main body includes a plurality of lobes contributing to its interior. The lobes project perpendicular to and away from the longitudinal axis of the main body with the interior of each projecting lobe sized to accommodate at least one projecting fin of the payload. The top of the main body ... |
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| Appendage and Viscous Forces for Ship Motions in Waves |
SEP 2004 |
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| Authors:
Kevin A. McTaggart; DEFENCE RESEARCH AND DEVELOPMENT ATLANTIC DARTMOUTH (CANADA)
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 | This report describes the prediction of appendage and viscous forces in Defence Research and Development Canada (DRDC) Atlantic's ShipMo3D library for ship motions in waves. Previously, the ShipMo3D library considered only hull forces due to potential flow. Inclusion of appendage and viscous forces is essential for accurate prediction of ship sway, roll, and yaw motions. Appendage forces are caused by added mass, lift, and viscous effects. Hull viscous forces are ... |
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| A Winglet for the Trailing End of Towed Flexible Underwater Lines |
23 AUG 2004 |
12 pages |
| Authors:
Neil J. Dubois; Bruce E. Sandman; DEPARTMENT OF THE NAVY WASHINGTON DC
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| A winglet for mounting on a trailing end of a flexible line to be towed by an underwater vehicle includes an internal collar member for connection to an inside surface of the line at the trailing end thereof, an outer collar member for connection to an outside surface of the line outboard of the internal collar, and connection means for fixing the internal and outer collar members to the line ... |
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| Exploiting the Innate Antitumor Activity of Human Gamma-Delta T-Cells for the Treatment of Prostate Cancer |
APR 2004 |
20 pages |
| Authors:
Richard D. Lopez; ALABAMA UNIV IN BIRMINGHAM
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| We initially identified and characterized a CD2-mediated, interleukin (IL)-12-dependent signaling pathway which inhibits apoptosis in mitogen- stimulated human gamma delta-T cells. We have since exploited this pathway to develop the methodologies allowing the large-scale ex vivo expansion of viable apoptosis-resistant gamma delta-T cells. We have shown that apoptosis-resistant human gamma delta-T cells retain significant innate, major histocompatibility complex (MMC)-unrestricted cytotoxicity against human prostate cancer cell lines. Purpose and scope: The ... |
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| Lateral Control Jet Aerodynamic Predictions for a 2.75-in Rocket Testbed Munition |
APR 2004 |
40 pages |
| Authors:
Paul Weinacht; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| The aerodynamic performance of lateral control jets for a 2.75-in rocket testbed munition has been investigated using a sophisticated numerical technique. The computational approach utilized a finite difference-based overset gridding approach to predict the interaction of the lateral control jet with the external flow around the munition and the resulting effect on the lateral control jet performance. The jet interaction effect was found to be an important contributor to the ... |
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| Three-Dimensional Analysis of Crack in Centrally Perforated Photoelastic Cylinders under Internal Pressure |
12 FEB 2004 |
5 pages |
| Authors:
C. T. Liu; C. W. Smith; AIR FORCE RESEARCH LAB EDWARDS AFB CA SPACE AND MISSILE PROPULSION DIV
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| In this study, the frozen stress photoelastic method was used to investigate the three-dimensional effect on the crack growth behavior in a centrally perforated circular cylinder under internal pressure. The inner surface of the cylinder had a star shape, which consisted of six fins. The specimens were capped at the ends and pressurized internally above critical temperature after real cracks were introduced at the fin tip. After growing to a ... |
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| Gravity-Actuated Submarine Antenna |
11 FEB 2004 |
28 pages |
| Authors:
David F. Rivera; DEPARTMENT OF THE NAVY WASHINGTON DC
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| An antenna including a feed tube with radial fins and 7 circular plates at the ends of the tube and fins thereby forming a boundary for a plurality of resonant cavities. Curved plates, connected to the tube by switches of a switching system, partially encompass and subtend to the length of the tube. Interior to the tube, a transmission line from an end plate terminus conducts radio-frequency energy from the ... |
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| Strength Enhancement and Application Development of Carbon Foam for Thermal Management Systems |
2004 |
10 pages |
| Authors:
Christopher Duston; Roland Watts; Steve Seghi; Barbara Carney; CERAMIC COMPOSITES INC MILLERSVILLE MD
|
| Carbon foam is recognized as having the great potential to replacement for metal fins in thermal management systems such as heat exchangers, space radiators, and thermal protection systems. An initial barrier to implementation was the inherent weakness and friability of the carbon foams. Ceramic Composites Inc. has demonstrated the ability to increase the compressive strength by 2 times through the treatment of the carbon foam ligaments with a uniform silicon ... |
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| Towable Submarine Mast Simulator |
06 OCT 2003 |
21 pages |
| Authors:
Duane M. Horton; DEPARTMENT OF THE NAVY WASHINGTON DC
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| This patent application discloses a submarine mast simulator as part of a buoyant tow body having a hydrodynamically shaped shell. The mast simulator includes a rigid lower mast section and an inflatable upper mast section extendable from the tow body. A plurality of stabilizer fins extend radially from the tail of the tow body, the fins being actuated to cause the ascent and descent of the tow body. A pressure ... |
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| Predicting the Cause of Failure in 120-mm Mortar Fins |
JUL 2003 |
13 pages |
| Authors:
J. A. Cordes; H. Rand; D. Carlucci; L. Reinhardt; S. Kerwien; ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER PICATINNY ARSENAL NJ PRECISION MUNITIONS AND DEMOLITION
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| During 2002, approximately 1500 120-mm mortars were tested at Yuma Proving Grounds, Arizona. Of the 1500 rounds, seven fell short of the 7200-m range requirement. Inspection of the short rounds indicated that short rounds lost one or more fins. This paper describes the structural analysis used to predict two proximal causes of failure. First, unequal pressure on one side of the fin can cause permanent bending, twisting, and breaking of ... |
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| An Experimental Study of a Pin-Fin Heat Exchanger |
JUN 2003 |
79 pages |
| Authors:
David Ramthun; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| A detailed experimental study has been carried out on the heat transfer and pressure drop characteristics of a compact heat exchanger with pin fins, A modular wind- tunnel with a rectangular cross-section duct-flow area was constructed that would accommodate the heat exchanger test section with varying pin designs. The flow in the tunnel was achieved through a suction-type blower, and a leading entrance length section was added to achieve predictable ... |
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| Vortex Effects in the Dynamics of Underwater Weapons |
MAR 2003 |
13 pages |
| Authors:
P. A. Lyes; A. P. Steer; BAE SYSTEMS WATERLOOVILLE (UNITED KINGDOM) UNDERWATER WEAPONS DIV
|
| As the control and mobility of submarines are improved to meet the challenges of the 21st-century security environment, so the capabilities of underwater weapons must keep pace with these developments. An underwater weapon is typically propelled by a pump-jet, controlled by an arrangement of movable lifting surfaces, and stabilized by fixed fins. The propulsor, fins, and control surfaces are situated close together at the tail, and close to the axis ... |
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| Submarine Countermeasure Propeller Protector |
16 DEC 2002 |
14 pages |
| Authors:
William P. Barker; DEPARTMENT OF THE NAVY WASHINGTON DC
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| A propeller protector for a countermeasure vehicle having a propeller shaft, a propeller fixed to the shaft, radial fins fixed on the vehicle and extending outwardly from the shaft, and a shield fixed to the fins and surrounding the propeller. The propeller protector includes a sleeve having an end wall at a first end thereof, and an open second end engaged with the vehicle, the first end and side walls ... |
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| Thermal Management Research for Power Generation. Delivery Order 0002 - Volume 1: Plain Fin Array Cooler for Electronics Cooling |
DEC 2002 |
35 pages |
| Authors:
Lanchao Lin; UES INC DAYTON OH
|
| A fin array cooler was developed to cool a substrate of high-heat flux electronics. Plain copper fin strips were soldered onto the substrate to minimize the contact thermal resistance between the electronics and heat sink. Two new types of fin arrays based on offset fin strips and aligned fin strips were employed in order to mitigate the thermal stress problem found in the integral finned substrate concept. The cooler with ... |
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| Numerical Investigation of Aerodynamics of Canard-Controlled Missile Using Planar and Grid Tail Fins. Part 1. Supersonic Flow |
SEP 2002 |
91 pages |
| Authors:
James DeSpirito; Milton E. Vaughn Jr.; W. D. Washington; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| Viscous computational fluid dynamic simulations were used to predict the aerodynamic coefficients and flowfield around a generic canard-controlled missile configuration in supersonic flow. Computations were performed for Mach 1.5 and 3.0, at six angles of attack between 0 and 10, with 0 and 10 canard deflection, and with planar and grid tail fins, for a total of 48 cases. Validation of the computed results was demonstrated by the very good ... |
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| Flight Motion of a Continuously Elastic Finned Missile |
JUN 2002 |
64 pages |
| Authors:
Charles H. Murphy; William H. Mermagen; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| The motion of elastic finned projectiles has been analyzed by various approximate theories. In this report the exact equations of small amplitude motion are derived for a symmetric missile. The aerodynamic and elastic symmetries are used to allow the use of complex variables to describe the lateral motion in a non-rotating coordinate system. Although the resulting equations are both ordinary and partial differential equations, frequencies and damping rates of free ... |
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| Analysis of Turbulence Models in a Cross Flow Pin Fin Micro-Heat Exchanger |
JUN 2002 |
59 pages |
| Authors:
Eric K. Lind; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| In this study, several turbulence models are analyzed in a 3-D finite element model of a micro-heat exchanger. The micro-heat exchanger consists of a narrow planar flow passage between parallel walls with small cylindrical pin fins spanning these walls with axes perpendicular to the direction of flow. Turbulence model performance is compared with baseline experimental data available in the literature that cover a range of low turbulent Reynolds numbers and ... |
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| Stress Intensity Factors and Crack Paths for Cracks in Photoelastic Motor Grain Models |
22 MAY 2002 |
10 pages |
| Authors:
C. W. Smith; D. M. Constantinescu; C. T. Liu; AIR FORCE RESEARCH LAB EDWARDS AFB CA SPACE AND MISSILE PROPULSION DIV
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| Computational analysis and two dimensional tensile tests on single motor grain fins suggest that cracks in fin tips are most likely to originate at the coalescence of the fin end tip radius with a small radius emanating from the side of the fin. Prior studies have indicated that under internal pressure, cracks on the fin axis are subject to similar stress peaks and may grow more readily than the former ... |
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| Alleviation of Buffet on the Twin-Tail Assemblies of High-Performance Aircraft (aasert) |
31 OCT 2001 |
19 pages |
| Authors:
Ali H. Nayfeh; Dean T. Mook; VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG DEPT OF ENGINEERING SCIENCE AND MECHANICS
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| We carried out experiments on a structural dynamic model of the twin- tail assembly of the F-15 fighter built by Professor Sathya Hanagud of Georgia Tech. The model was placed on a 250 lb shaker and subjected to a principal parametric excitation. We fixed the excitation amplitude and varied the excitation frequency around 18 Hz. For the same excitation amplitude and frequency, we found five possible responses depending on the ... |
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| Experimental Validation of Elliptical Fin Opening Behavior |
SEP 2001 |
31 pages |
| Authors:
James M. Garner; Paul Welnacht; Robert P. Kaste; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| An effort to improve the performance of ordnance has led to the consideration of the use of folding elliptical fins for projectile stabilization. A second order differential equation was used to model elliptical fin deployment history and accounts for deployment with respect to the geometric properties of the fin, the variation in fin aerodynamics during deployment, the initial yaw effect on fin opening, and the variation in deployment speed based ... |
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| Gene Regulation and Expression Pattern of the Growth Factor Pleiotrophin in Breast Cancer |
SEP 2001 |
13 pages |
| Authors:
Heinz J. List; GEORGETOWN UNIV WASHINGTON DC MEDICAL CENTER
|
| The growth factor plelotrophin (PTN) is a positive regulator of tumor angiogenesis. PTN is expressed in breast cancer cell lines and primary breast tumor specimens and has been discussed as one major factor for the malignant phenotype of human mammary carcinoma. The expression of FIN is regulated by at least two promoters, one that is species-conserved and one that is human- specific. The latter is generated by insertion of a ... |
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| Hi-Fidelity Simulation and Prediction of Helicopter Single Point External Load Stabilization |
SEP 2001 |
205 pages |
| Authors:
George E. Ehlers; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The helicopter has been used since its early development for external transport of large or bulky loads to small austere locations. Among the problems encountered as lift capability and airspeeds increased was that of divergent load oscillations due to load aerodynamics. The most problematic are the single point external loads displaying unsteady aerodynamics and coupled yaw-pendulum modes accounting for the instability of cargo containers. However, a lack of simulation models ... |
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| An Efficient All-Movable Fin Design for Military Aircraft |
06 AUG 2001 |
39 pages |
| Authors:
Jonathan E. Cooper; MANCHESTER UNIV (UNITED KINGDOM) SCHOOL OF ENGINEERING
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| This report results from a contract tasking University of Manchester as follows: A generic all-movable vertical tail will be designed (at the conceptual design level) with conventional and with active flexible technologies. The weight, performance and observable benefits of such designs will then be determined relative to the conventional design. The work will examine a range of different parameters including: Mach number both sub and supersonic speeds, attachment position, yaw ... |
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| Calculating Vortices for Finned Missiles Using the WIND Flow Solver |
JUN 2001 |
29 pages |
| Authors:
David J. Haroldsen; Walter B. Sturek; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The U.S. Army Research Laboratory is interested in applying state-of- the-art computational tools to the study of projectile aerodynamics at angle of attack and moderate Mach number. The WIND flow solver has been used to study the aerodynamics of two missile configurations. WIND successfully incorporates grids generated by the GridPro grid generation package. WIND gives good scalability and good overall performance on parallel computer platforms. This report discusses several aspects ... |
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| Hybrid Laminar Fin Investigations |
JUN 2001 |
10 pages |
| Authors:
V. Schmitt; J. P. Archambaud; K. H. Hortstmann; A. Quast; OFFICE NATIONAL D'ETUDES ET DE RECHERCHES AEROSPATIALES TOULOUSE (FRANCE)
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| In order to evaluate the HLFC concept which is seen as the most promising drag redaction technology for transport aircraft applications Airbus Industrie launched some years ago the laminar fin programme. The paper briefly describes the main phases of this programme I.e. the theoretical evaluation the experimental verification through adequate wind tunnel tests and the flight test demonstration with the Airbus A320 n 1 as testbed. It will be shown ... |
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| Offset Piezoceramic Stack Actuators and Acceleration Feedback Control for Tail Buffet Alleviation of a High Performance Twin Tail Aircraft: Robustness Issues |
JUN 2001 |
12 pages |
| Authors:
S. Hanagud; M. B. de Noyer; GEORGIA INST OF TECH ATLANTA SCHOOL OFAEROSPACE ENGINEERING
|
| In high performance twin-tail aircraft tail buffet occurs when unsteady pressures associated with separated flow excite the modes of the vertical fin structural assemblies At high angles of attack flow separates and is convected by the geometry of the wing-fuselage interface toward the vertical tails. This phenomenon. along with the aeroelastic coupling of the tail structural assembly results in vibrations that can shorten the fatigue life of the empennage assembly ... |
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| Stress Intensity Factors and Paths for Cracks in Photoelastic Motor Grain Models Under Internal Pressure |
20 APR 2001 |
11 pages |
| Authors:
C. W. Smith; D. M. Constantinescu; C. T. Liu; VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG DEPT OF ENGINEERING SCIENCE AND MECHANICS
|
| Computational analysis and two-dimensional tensile tests on single motor grain fins suggest that cracks in fin tips are most likely to originate at the coalescence of a fin end tip radius, with a small radius from the side of the fin. Some manufacturers have also noticed defects formed during casting at the fin tip on the fin axis. The following is an experimental investigation utilizing frozen stress photoelastic models of ... |
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| Interaction of Vortex Breakdown with a Flexible Fin and its Control |
13 FEB 2001 |
25 pages |
| Authors:
Ismet Gursul; BATH UNIV (UNITED KINGDOM) DEPT OF MECHANICAL ENGINEERING
|
| This report results from a contract tasking University of Bath as follows: The contractor will investigate the fin buffeting caused by vortex breakdown and its control. In this phase, a flexible fin will be designed and fabricated. It consists of a thin brass spar surrounded by several balsa wood segments to provide aerodynamic shaping. Fin vibration levels will be sensed by root strain gages and tip accelerometers. Unsteady surface pressure ... |
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| A Compendium of Bonded Repairs Applied to the PC9/A Full Scale Fatigue Test Article During Testing |
NOV 2000 |
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| Authors:
Richard Bartholomeusz; Rowan Geddes; Peter Chalkley; DEFENCE SCIENCE AND TECHNOLOGY ORGANISATION MELBOURNE (AUSTRALIA)
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| A number of bonded composite repairs were applied to the PC9/A full- scale fatigue test article during its fatigue test to help achieve the target of greater than 50,000 simulated flight hours. The aim of the test was to provide RAAF with data to enable the through-life structural fatigue management of PC9/A aircraft in their fleet Bonded repairs were applied to cracks that occurred in the wing centre-section on the ... |
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| Wing and FIN Buffet on the Standard Dynamics Model |
01 OCT 2000 |
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| Authors:
X. Z. Huang; FIELD TECHNOLOGY INC LONG BEACH CA
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| For modern aircraft with higher sweep angles flying at higher incidence, unsteady and burst vortex flow in the vicinity of the wing and downstream lifting surface lead to strong unsteady airloads and buffeting'. Thus, investigations were conducted in the Institute for Aerospace Research (lAR) Low Speed Wind Tunnel (LSWT)2 to study the buffet characteristics of the Standard Dynamics Model (SDM)3, a generic fighter aircraft configuration. Since the spectrum of the ... |
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| F-5 Wing & F-5 Wing + TIP Store |
01 OCT 2000 |
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| Authors:
Evert G. Geurts; NATIONAL AEROSPACE LAB AMSTERDAM (NETHERLANDS)
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| This data set relates to a transonic wind tunnel investigation carried out in l977 on an oscillating, slightly modified model of the outer part of a Northrop F-5 wing with and without an external store. The store represented an AlM-9J missile including its launcher. These tests were reported in references 1,2 and 3. The model proceeded from an F-5 wing model for subsonic tests by a slight reduction of the ... |
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| Investigation of the Unique Cryogenic Pumping System of the CHAFF-IV spacecraft-Thruster Interaction Facility |
09 JUL 2000 |
9 pages |
| Authors:
Andrew D. Ketsdever; Marcus P. Young; Andrew Jamison; Brian Eccles; E. P. Muntz; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE WEST
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| Chamber -IV of the Collaborative High Altitude Flow Facility was designed to obtain high fidelity spacecraft- thruster interaction data. CHAFF-IV uses a total chamber pumping concept by lining the entire chamber with an array of cryogenically cooled, radial fins. Details of Monte Carlo numerical simulation and experimental investigation of the radial fin target array pumping efficiency are presented. |
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| Simulation and Analysis of Wing Rock Physics for a Generic Fighter Model with Three Degrees-of-Freedom |
JUL 2000 |
115 pages |
| Authors:
Ahmed A. Saad; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| Modern fighter designs have been associated with lateral self-excited oscillations own as "Wing Rock". Simulations of wing rock by flow visualization utilities have been encouraged to develop a complete understanding of the fluid mechanism that drives fl%e motion as well as for prediction purposes. Previous windiwater tunnel simulations have been limited to a single degree-ofifreedom (DoF) in roll. In this study, for the first time, wing rock is computationally simulated ... |
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