SCIENTIFIC AND TECHNICAL AEROSPACE REPORTS
A Biweekly Publication of the National Aeronautics and Space Administration
VOLUME 43, ISSUE 16 - AUGUST 12, 2005
02 AERODYNAMICS
Includes aerodynamics of flight vehicles, test bodies, airframe components and combinations, wings, and control surfaces.
Also includes aerodynamics of rotors, stators, fans, and other elements of turbomachinery.
For related information see also 34 Fluid Mechanics and Thermodynamics.
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20050188665 Air Force Inst. of Tech., Wright-Patterson AFB, OH USA
A Study in Drag Reduction of Close Formation Flight Accounting for Flight Control Trim Positions and Dissimilar Formations
Morgan, Michael T.; Mar. 2005; 130 pp.; In English; Original contains color illustrations Report No.(s): AD-A434312; AFIT/GAE/ENY/05-M13; No Copyright; Avail: CASI; A07, Hardcopy
This thesis further defines the position of greatest fuel savings benefit for the trail aircraft flying in a two-ship formation. The HASC95 vortex lattice code was used for the examination. Investigations of a similar formation of F-16 aircraft and a dissimilar formation of a lead KC-135 aircraft and a trail F-16 aircraft were conducted. The analyses determined the effects of varying airspeed on the optimal position. In addition, flight control surface deflections were taken into account during the analyses. Both investigations trimmed the aircraft in the yaw and roll axes to determine the optimal savings. The similar analysis was conducted at an altitude of 20,000 feet and three airspeeds: cruise speed of 300 knots, maximum range airspeed of 271 knots, and maximum endurance airspeed of 211 knots. The savings for the trail aircraft were determined to be 16%, 21%, and 34%, respectively, at a constant wing tip overlap of 13.5% of the wingspan. The dissimilar formation was completed at an altitude of 20,000 feet and 300 knots airspeed. This resulted in a 26% savings for the trail aircraft with a wing tip overlap of 16.7% of its wingspan. A flight test was flown for the similar formation profile of F-16s. The flight test investigated the change in vertical positioning and lateral spacing from the first analysis and captured data at 300 knots. The results of the flight test were inconclusive. However, the determined area of apparent savings was bounded by 7.9% to 19.9% wing tip overlap and -3.2% to -7.3% vertical separation. At the bounds, fuel savings of 12% and 13% +/-7% were observed. The drag savings profile had the capability to increase the range of existing airframes, providing the benefit at no cost. The analytical study was conducted at the Air Force Institute of Technology, Wright-Patterson AFB. The flight test was conducted at the U.S. Air Force Test Pilot School, Edwards AFB, California. DTIC
Aircraft Pilots; Airspeed; Drag Reduction; Flight Control; Formation Flying; Fuel Consumption; Optimization
20050192561 George Washington Univ., Washington, DC, USA
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Program of Research in Flight Dynamics, The George Washington University at NASA Langley Research Center
Murphy, Patrick C., Technical Monitor; Klein, Vladislav; [2005]; 11 pp.; In English Contract(s)/Grant(s): NCC1-03004; No Copyright; Avail: CASI; A03, Hardcopy
The program objectives are fully defined in the original proposal entitled Program of Research in Flight Dynamics in GW at NASA Langley Research Center, which was originated March 20, 1975, and in the renewals of the research program from January 1, 2003 to September 30, 2005. The program in its present form includes three major topics: 1. the improvement of existing methods and development of new methods for wind tunnel and flight data analysis, 2. the application of these methods to wind tunnel and flight test data obtained from advanced airplanes, 3. the correlation of flight results with wind tunnel measurements, and theoretical predictions. Derived from text
Wind Tunnel Tests; Aerodynamics; Research Projects; Mathematical Models; Flight Characteristics
20050194597 Bureau of Industry and Security, Washington, DC, USA
National Security Assessment of the U.S. Aerial Delivery Equipment Industry. A Joint Assessment with U.S. Army Soldier Biological and Chemical Command
January 2005; 96 pp.; In English Report No.(s): PB2005-107382; No Copyright; Avail: CASI; A05, Hardcopy
Since their first major deployment in 1942, parachutes have been an important tool in the arsenal of the USA armed forces, enabling the delivery of troops and equipment to inaccessible locations with speed and often with surprise. Following the initial use of parachutes in World War II for large-scale troop deployments, the technology evolved rapidly to support a broad range of aerial delivery systems for cargo and other payloads. The technological and manufacturing base of the air delivery systems used by the armed forces is now many decades old and is well established. The U.S. military relies on these systems not only in times of conflict, but also for assisting in humanitarian relief operations around the globe. In recent years, however, the Department of Defense (DOD) has experienced some problems in timely delivery of parachute orders from industry and has been concerned about the ability of the U.S. Army to procure parachute systems quickly in a time of national need. A detailed assessment of the health and competitiveness of the industry, specifically addressing its ability to meet future DOD needs, was requested by the U.S. Army Soldier Biological and Chemical Command (SBCCOM), a subordinate unit of the U.S. Army Materiel Command (AMC). The U.S. Department of Commerce, Bureau of Industry and Security, was asked to conduct the assessment. NTIS
Air Cargo; Air Drop Operations; Aircraft Equipment; Delivery; Industries; Security
20050196086 Defence Science and Technology Organisation, Victoria, Australia
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A Review of Australian and New Zealand Investigations on Aeronautical Fatigue During the Period April 2003 to March 2005
Clark, Graham; May 2005; 84 pp.; In English; Original contains color illustrations Report No.(s): AD-A434937; DSTO-TN-0624; DODA-AR-013-387; No Copyright; Avail: Defense Technical Information Center (DTIC)
This document has been prepared for presentation to the 29th Conference of the International Committee on Aeronautical Fatigue scheduled to be held in Hamburg, Germany, 6th and 7th June 2005.
Brief summaries and references are provided on the aircraft fatigue research and associated activities of research laboratories, universities, and aerospace companies in Australia and New Zealand during the period April 2003 to March 2005.
The review covers fatigue related research programs as well as fatigue investigations on specific military and civil aircraft.
DTIC
Aeronautical Engineering; Australia; New Zealand
20050196639 Georgia Tech Research Inst., Atlanta, GA, USA
The Application of Pneumatic Aerodynamic Technology to Improve Drag Reduction, Performance, Safety, and Control of Advanced Automotive Vehicles
Englar, Robert J.; Proceedings of the 2004 NASA/ONR Circulation Control Workshop, Part 2; June 2005, pp. 957-995; In English; See also 20050196628; Original contains color illustrations; No Copyright; Avail: CASI; A03, Hardcopy
Blown aircraft aerodynamic technology has been developed and applied to entrain separated flow fields, significantly reduce drag, and increase the fuel economy of Heavy Vehicles and Sports Utility Vehicles (SUVs). These aerodynamic improvements also lead to increases in stability, control, braking, and traction, thus enhancing safety of operation.Wind-tunnel results demonstrating model Heavy Vehicle drag coefficient reductions of up to 84% due to blowing and related configuration improvement are reviewed herein. Tunnel data confirming the elimination of directional instability due to side-winds plus generation of aerodynamic forces which are not currently used for control of large vehicles are also shown. These data have guided the design and modification of a full-scale road-test vehicle. Initial confirmation road test results of this patented concept on the modified blown HV rig are presented. An SAE Type-II Fuel Economy test was also conducted. Here, various blowing configurations were tested, and results were compared to a baseline reference tractor-trailer to confirm the improved fuel economy due to blowing. Full-scale wind-tunnel tests of this pneumatic technology applied to a GM Suburban SUV were also conducted, and the positive effects of blowing for drag reduction, vehicle aerodynamic stability, and operational safety are shown. Comparative results presented include wind-tunnel data for both unblown and blown configurations, full-scale blowing and fuel-economy data, and comparisons to smaller-scale blown Pneumatic Heavy Vehicle experimental results. Author
Aerodynamic Forces; Aerodynamic Stability; Motor Vehicles; Pneumatics; Flow Distribution; Drag Reduction
20050196641 Army Research Lab., Aberdeen Proving Ground, MD, USA
Time-Accurate Simulations of Synthetic Jet-Based Flow Control for a Spinning Axisymmetric Body
Sahu, Jubaraj; Proceedings of the 2004 NASA/ONR Circulation Control Workshop, Part 2; June 2005, pp. 689-721; In English; See also 20050196628; Original contains color and black and white illustrations; No Copyright; Avail: CASI; A03, Hardcopy
This paper describes a computational study undertaken to determine the aerodynamic effect of tiny unsteady synthetic jets as a means to provide the control authority needed to maneuver a spinning projectile at low subsonic speeds. Advanced Navier-Stokes computational techniques have been developed and used to obtain numerical solutions for the unsteady jet-interaction flow field at subsonic speeds and small angles of attack. Unsteady numerical results show the effect of the jet on the flow field and on the aerodynamic coefficients. The unsteady jet is shown to substantially alter the flow field both near the jet and the base region of the projectile that in turn affects the forces and moments even at zero degree angle of attack. The results have shown the potential of computational fluid dynamics to provide insight into the jet interaction flow fields and provided guidance as to the locations and sizes of the jets to generate the maximum control authority to maneuver a projectile to hit its target with precision. Author
Axisymmetric Bodies; Computational Fluid Dynamics; Unsteady Flow; Angle of Attack; Aerodynamic Coeffýcients; Flow Distribution
20050196643 Georgia Tech Research Inst., Atlanta, GA, USA
Aerodynamic Heat Exchanger: A Novel Approach to Radiator Design Using Circulation Control
Gaeta, R. J.; Englar, R. J.; Blaylock, G.; Proceedings of the 2004 NASA/ONR Circulation Control Workshop, Part 2; June 2005, pp. 997-1021; In English; See also 20050196628; Original contains color and black and white illustrations; No Copyright; Avail: CASI; A03, Hardcopy
GTRI has recently been developing pneumatic aerodynamic concepts for application to Heavy Vehicles under a Department of Energy contract through the Oak Ridge National Laboratory (ORNL). A related application under development is a novel heat exchanger known as the Aerodynamic Heat Exchanger (AHE). This patented device employs airfoil/wing aerodynamic pressure differences to induce large mass flows across a radiator installed inside a wing. GTRI has recently completed an in-house wind tunnel test of this concept. The objective of this proposed effort was to perform a wind-tunnel evaluation of the AHE and establish the feasibility of the concept. A 2D wing was fabricated with a removable center section. A radiator core was integrated into this section of the wing. A conventional radiator core (based on a Visteon design) and two cores made from carbon foam were tested. The carbon foam cores were designed and provided to GTRI by ORNL. Hot water was allowed to pass through the inside of the wing while freestream, wind tunnel air passed over (and through) the wing. Heat rejected by the radiator was measured as well as lift and drag. Results indicated that the concept is feasible and can provide an effective means to reduce vehicle drag by reducing the drag due to conventional radiators. Author
Pneumatics; Aerodynamic Heating; Heat Exchangers; Airfoils; Mass Flow; Free Flow; Drag Reduction
20050196658 QSS Group, Inc., Cleveland, OH, USA
Vortex Rings Generated by a Shrouded Hartmann-Sprenger Tube
DeLoof, Richard L., Technical Monitor; Wilson, Jack; July 2005; 20 pp.; In English; 35th Fluid Dynamics Conference and Exhibit, 6-9 Jun. 2005, Toronto, Ontario, Canada Contract(s)/Grant(s): NAS3-00145; WBS 22-708-03-05 Report No.(s): NASA/CR-2005-213576; AIAA Paper 2005-5163; E-15041-2; No Copyright; Avail: CASI; A03, Hardcopy
The pulsed flow emitted from a shrouded Hartmann-Sprenger tube was sampled with high-frequency pressure transducers and with laser particle imaging velocimetry, and found to consist of a train of vortices. Thrust and mass flow were also monitored using a thrust plate and orifice, respectively. The tube and shroud lengths were altered to give four different operating frequencies. From the data, the radius, velocity, and circulation of the vortex rings was obtained. Each frequency corresponded to a different length to diameter ratio of the pulse of air leaving the driver shroud. Two of the frequencies had length to diameter ratios below the formation number, and two above. The formation number is the value of length to diameter ratio below which the pulse converts to a vortex ring only, and above which the pulse becomes a vortex ring plus a trailing jet. A modified version of the slug model of vortex ring formation was used to compare the observations with calculated values. Because the flow exit area is an annulus, vorticity is shed at both the inner and outer edge of the jet. This results in a reduced circulation compared with the value calculated from slug theory accounting only for the outer edge. If the value of circulation obtained from laser particle imaging velocimetry is used in the slug model calculation of vortex ring velocity, the agreement is quite good. The vortex ring radius, which does not depend on the circulation, agrees well with predictions from the slug model. Author
Hartmann-Sprenger Tubes; Vortex Rings; Shrouds; Unsteady Flow
20050196736 National Transportation Safety Board, Washington, DC USA
National Transportation Safety Board Aircraft Accident Report: Hard Landing, Gear Collapse, Federal Express Flight 647, Boeing MD-10-10F, N364FE, Memphis, Tennessee, on December 18, 2003
May 17, 2005; 122 pp.; In English Report No.(s): PB2005-910401; NTSB/AAR-05/01; No Copyright; Avail: CASI; A06, Hardcopy
This report explains the accident involving Federal Express flight 647, a Boeing MD-10-10F N364FE, which crashed while landing at Memphis International Airport (MEM), Memphis, Tennessee. Safety issues in this report focus on flight crew performance, emergency evacuations, MEM air traffic control and aircraft rescue and firefighting issues, and flight data recorder reliability. NTIS
Accident Investigation; Collapse; Hard Landing; Landing Gear; Safety; Safety Management; Transportation
20050198856 NASA Langley Research Center, Hampton, VA, USA
Turbulent Vortex-Flow Simulation Over a 65 deg Sharp and Blunt Leading-Edge Delta Wing at Subsonic Speeds
Ghaffari, Farhad; July 2005; 47 pp.; In English; Original contains color and black and white illustrations Contract(s)/Grant(s): WU 23-762-45-UG Report No.(s): NASA/TM-2005-213781; L-19140; No Copyright; Avail: CASI; A03, Hardcopy
Turbulent thin-layer, Reynolds-Averaged Navier-Stokes solutions, based on a multi-block structured grid, are presented for a 65 deg delta wing having either a sharp leading edge (SLE) or blunt leading edge (BLE) geometry. The primary objective of the study is to assess the prediction capability of the method for simulating the leading-edge flow separation and the ensuing vortex flow characteristics. Computational results are obtained for two angles of attack of approximately 13 and 20 deg, at free-stream Mach number of 0.40 and Reynolds number of 6 million based on the wing mean aerodynamic chord. The effects of two turbulence models of Baldwin-Lomax with Degani-Schiff (BL/DS) and the Spalart-Allmaras (SA) on the numerical results are also discussed. The computations also explore the effects of two numerical flux-splitting schemes, i.e., flux difference splitting (fds) and flux vector splitting (fvs), on the solution development and convergence characteristics. The resulting trends in solution sensitivity to grid resolution for the selected leading-edge geometries, angles of attack, turbulence models and flux splitting schemes are also presented. The validity of the numerical results is evaluated against a unique set of experimental wind-tunnel data that was obtained in the National Transonic Facility at the NASA Langley Research Center. Author
Computational Fluid Dynamics; Navier-Stokes Equation; Boundary Layer Separation; Delta Wings; Flow Characteristics; Separated Flow; Turbulence Effects; Vortices; Multiblock Grids; Structured Grids (Mathematics); Subsonic Speed
Source: NASA.
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