| Fundamental Physics and Practical Applications of Electromagnetic Local Flow Control in High Speed Flows |
22 Feb 2010 |
18 pages |
| Authors:
Doyle D Knight; Kellie Anderson; RUTGERS - THE STATE UNIV PISCATAWAY NJ DEPT OF MECHANICAL AND AEROSPACE ENGINEERING
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 | The report summarizes two major achievements in Electromagnetic Local Flow Control (ELFC) in high speed flows. The first achievement is the demonstration of the effective and efficient reduction of pressure drag on a blunt cylinder in supersonic flow using pulsed heated filaments. Numerical simulations indicate drag reduction up to 30% with power requirements typically 1% of the power saved through drag reduction. No adverse effect on heat transfer to the ... |
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| A New Eddy-Based Model for Wall-Bounded Turbulent Flows |
11 Feb 2010 |
10 pages |
| Authors:
Ivan Marusic; MELBOURNE UNIV (AUSTRALIA) DEPT OF MECHANICAL AND MANUFACTURING ENGINEERING
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| Fundamental studies of wall-bounded turbulent flows were conducted with the aim of developing models that capture its correct spectral behavior and that allow prediction of Reynolds stress distributions in wall-bounded flows across a large range of Reynolds numbers. The model accounts for the recent new findings in wall turbulence concerning large-scale motions and the interaction with the wall and drag producing mechanisms. The experimental results shed light on the important ... |
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| Numerical Computation of the Full Set of Equations for Magneto-Fluid Dynamics |
11 Feb 2010 |
19 pages |
| Authors:
Robert W MacCormack; STANFORD UNIV CA DEPT OF AERONAUTICS AND ASTRONAUTICS
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| This report presents numerical procedures for solving the equations of Magneto-Fluid-Dynamics (MFD). These equations consist of the Navier-Stokes equations coupled to the full set of Maxwell's equations. They govern flow within electromagnetic fields. The primary interest to the Air Force of this work is flow control about aerodynamic vehicles and thrust enhancement within scramjet engines via the interaction of external electromagnetic fields, produced on board, with the high speed flow ... |
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| Gravity-Wave Dynamics in the Atmosphere |
01 Feb 2010 |
79 pages |
| Authors:
Triantaphyllos R Akylas; MASSACHUSETTS INST OF TECH CAMBRIDGE
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| Motivated by reports of accidents in high-altitude aircraft flights due to unforecast turbulence caused by gravity waves over mountain ranges, this research program aimed to advance the theoretical understanding of physical mechanisms responsible for the generation of gravity waves by wind over orography. Specifically, a systematic study was made of the Earth's rotation under various atmospheric conditions. It was found that rotation can contribute to significantly increased gravity-wave activity when ... |
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| Form, Function and Flow in the Plankton: Jet Propulsion and Filtration by Pelagic Tunicates |
Feb 2010 |
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| Authors:
Kelly R Sutherland; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
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 | Trade-offs between filtration rate and swimming performance among several salp species with distinct morphologies and swimming styles were compared. Small-scale particle encounter at the salp filtering apparatus was also explored. Observations and experiments were conducted at the Liquid Jungle Lab, off the Pacific coast of Panama in January 2006 through 2009. First, time-varying body volume was calculated by digitizing salp outlines from in situ video sequences. The resulting volume flow ... |
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| Renewable Energy Testing Center for US Army Contract W15QKN-05-D-0030 Task 5 RETC, WBS #4.6.0 |
Feb 2010 |
74 pages |
| Authors:
Jodie Crandell; George Crandell; TECHNIKON LLC
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| Research for the Renewable Energy Testing Center is intended to provide validation of advanced processes that generate renewable energy and reduce energy usage compared to conventional processes. This report covers the work performed under Task #5 of contract W15QKN-05-D-0030. Specific areas covered includes the evaluation of three alternative energy technologies on the conversion of biomass to synthetic gas and liquid fuels. This includes a Red Lion gasifier, ACTI gasification and ... |
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| Active Control of High Reynolds Number Supersonic Jets Using Plasma Actuators |
Feb 2010 |
65 pages |
| Authors:
Mo Samimy; Igor Adamovich; OHIO STATE UNIV COLUMBUS DEPT OF MECHANICAL ENGINEERING
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| Active flow control of jets with Localized Arc Filament Plasma Actuators (LAFPAs) is conducted over a wide range of the fully expanded jet Mach numbers (M(J) or simply jet Mach number). The jet Mach numbers covered in the present research are 0.9 (with a converging nozzle), 1.2 (overexpanded), 1.3 (perfectly expanded), and 1.4 (underexpanded) with a design Mach number 1.3. Additionally, limited experiments are carried out for an M(J) = ... |
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| Enhancement of Grain Refined Microstructure in a Nanostructured Metals via Ultrahigh Pressure Hydrostatic Consolidation Process - Construction of Master Sintering Curve (MSC) and Its Application to Densification of Al-Mg Alloy |
30 Jan 2010 |
9 pages |
| Authors:
Sangmok Lee; ASIAN OFFICE OF AEROSPACE RESEARCH AND DEVELOPMENT APO AP 96337-0007
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| Previously Al-Mg alloy was densified by hot isostatic processing and subsequently consolidated by hydrostatic extrusion. Through this process high strength and high formability nanostructured bulk Al-Mg alloy was fabricated. However, it is important to handle parametric control in powder metallurgical processing in terms of relative density, which is closely associated with its mechanical properties in acquiring a material of a desired property. At current stage processing parameter of density function ... |
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| Direct Phase-Resolved Simulation of Large-Scale Nonlinear Ocean Wave-Field |
27 Jan 2010 |
9 pages |
| Authors:
Dick K Yue; Yuming Liu; MASSACHUSETTS INST OF TECH CAMBRIDGE CENTER FOR OCEAN ENGINEERING
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| The objective of this research is to develop a new powerful capability, which is called SNOW (simulation of nonlinear ocean wave-field), for predicting the evolution of large-scale nonlinear wavefields using direct phase-resolved simulations. Unlike the phased-averaged approaches, SNOW models the key physical mechanisms such as nonlinear wave-wave, wave-current, wave-wind and wave-bottom interactions and wave breaking dissipation in a direct physics-based context. SNOW is now capable of simulating the nonlinear evolution ... |
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| Phase-Resolved Reconstruction and Forecast of Ocean Wavefields Using Scanning-Sensing Wave Measurements |
26 Jan 2010 |
7 pages |
| Authors:
Dick K Yue; Yuming Liu; MASSACHUSETTS INST OF TECH CAMBRIDGE CENTER FOR OCEAN ENGINEERING
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| This research focuses on the understanding of feasibility and reliability of deterministic reconstruction and (short-time) forecasting of realistic ocean wavefield evolution using phase-resolved wavefield simulations together with radar-sensed wave data. Direct comparisons between the reconstructed and forecasted wavefields are obtained. The validity, efficacy and limitation of the overall approach are evaluated and quantified. |
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| Measurements and Modeling of the Mean and Turbulent Flow Structure in High-Speed Rough-Wall Non-Equilibrium Boundary Layers |
25 Jan 2010 |
75 pages |
| Authors:
Rodney D Bowersox; Isaac W Ekoto; TEXAS ENGINEERING EXPERIMENT STATION COLLEGE STATION
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| The response of a supersonic high Reynolds number turbulent boundary layer flow subjected to mechanical distortions was experimentally examined. Local disturbances were introduced via small-scale wall patterns, and global distortions were induced through streamline curvature driven pressure gradients. Local surface topologies included k-type diamond and d-type square elements; a smooth wall was examined for comparison purposes. Three global distortions were studied with each of the three surface topologies. Measurements included ... |
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| Toward Developing a Hydrodynamic Flow & Inundation Model of the Lower Pearl River |
20 Jan 2010 |
9 pages |
| Authors:
Paul McKay; Cheryl A Blain; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
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| The lower Pearl River in Mississippi and Louisiana flows through extensive areas of intertidal marshes and floodplains and is subject to frequent floods due to upstream flows, local runoff and tidal and storm forcing. In order to improve flow and flood prediction capabilities, a hydrodynamic flow and inundation model for the lower Pearl River is being developed using ADCIRC by the river modeling group at the Naval Research Laboratory at ... |
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| Turbulent Drag Reduction Using Micro and Nanotextured Ultrahydrophobic Surfaces |
Jan 2010 |
17 pages |
| Authors:
Jonathan P Rothstein; MASSACHUSETTS UNIV AMHERST
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| This final report documents the findings of our research project which demonstrated through a combination of experimental measurements and numerical simulations that ultrahydrophobic surfaces can be used to delay the transition to turbulence and dramatically reduce drag in both external and internal turbulent flows. These enhancements should have a profound effect on a huge variety of existing technologies, resulting in benefits ranging from a reduction in the pressure drop in ... |
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| Turbomachinery Fluid Mechanics and Control |
Jan 2010 |
46 pages |
| Authors:
Steven L Puterbaugh; David Car; S Todd Bailie; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
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| Slot jet flow control concepts were developed and explored for the application to axial compressor stators. The concepts were demonstrated in a high speed wind tunnel to simulate a highly loaded stator passage. The midspan boundary layer flow could be forced to attach most effectively with addition of streamwise vorticity (vortex generators and discrete jets) however the endwalls continue to be poorly behaved until large fractions of the overall flow ... |
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| Jet-Like Flow and Thrust From a Flexible Flapping Foil in Stationary Fluid |
29 Dec 2009 |
19 pages |
| Authors:
Jaywant H Arakeri; Sachin Y Shinde; INDIAN INST OF SCIENCE BANGALORE (INDIA)
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| Many lifting and propulsive surfaces in Nature are structurally flexible. How important is this flexibility on the lift and thrust forces generated and on the efficiency is an important and open question. The objective of the present work is to study some aspects of the unsteady flow associated with flapping flexible foils. The present research aims to experimentally study the effect of chordwise flexibility on the flow past a flexible ... |
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| Carbon Dioxide Injection for Hypervelocity Boundary Layer Stability |
15 Dec 2009 |
18 pages |
| Authors:
Ross M Wagnild; Graham V Candler; Ivett A Leyva; Joes S Jewell; Hans G Hornung; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
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| An experimental method for introducing carbon dioxide as a means of stabilizing a hypervelocity boundary layer over a slender bodied vehicle is investigated through the use of numerical simulations. In the current study, two different test bodies are examined. The first is a five-degree-half-angle cone currently under research at the T5 Shock Tunnel with a four cm porous wall insert used to transpire gas into the boundary layer. The second ... |
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| System Architecture for Anti-Ship Ballistic Missile Defense (ASBMD) |
Dec 2009 |
231 pages |
| Authors:
Jean Hobgood; Kimberly Madison; Geoffrey Pawlowski; Steven Nedd; Michael Roberts; Paige Rumberg; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF SYSTEMS ENGINEERING
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| Recent studies suggest that China is developing a new class of ballistic missiles that can be used against moving targets, such as ships. One such technology is anticipated to cover a range of 2,000 kilometers and operate at a speed of Mach 10. The threat is also capable of maneuvering both during the midcourse and terminal flight phases for the purposes of guidance, target acquisition, and countermeasures. This threat could ... |
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| Investigation of Shock Wave Attenuation in Porous Materials |
Dec 2009 |
106 pages |
| Authors:
Boey C Wai; CENTER FOR EDGE POWER MONTEREY CA
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| This thesis investigates the use of porous materials in a multi-layered armor concept. The prototype layered structure consists of an initial high-strength material to slow down the projectile and cause significant plastic deformation, followed by an orthotropic wave-spreading layer to spread shock waves laterally away from the axis of penetration and subsequently attenuate the shock waves by using a porous material to convert kinetic energy into internal energy. Based on ... |
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| Flow Measurements Using Particle Image Velocimetry in the Ultra Compact Combustor |
Dec 2009 |
210 pages |
| Authors:
Levi M Thomas; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
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| Velocity measurements were performed using the Particle Image Velocimetry (PIV) technique on the Ultra Compact Combustor (UCC) test rig at the Air Force Institute of Technology (AFIT). Velocity patterns and time-averaged turbulence statistics were calculated for data taken with the UCC burning hydrogen fuel in the straight cavity vane and curved cavity vane configurations. The equivalence was varied from 0.7 to 1.5, while the ratio of cavity air to main ... |
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| Evaluation and Improvement of the PBD-X/MTFLOW Propulsor Analysis Software |
Dec 2009 |
40 pages |
| Authors:
Thad J Michael; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD
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| The software suite PBD-X/MTFLOW has been exercised for evaluation with both waterjet pumps and open propellers. PBD-X is a lifting surface propeller analysis code for steady conditions. MTFLOW is an axisymmetric Euler solver used to solve the axisymmetric component of the flow field inside of a waterjet pump or in and around a propeller. The results of the PBD-X/MTFLOW calculations were compared with PBD-14/MTFLOW calculations. PBD-14 is an earlier lifting ... |
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| Analysis of a Non-Developing Tropical Circulation System During the Tropical Cyclone Structure (TCS08) Field Experiment |
Dec 2009 |
92 pages |
| Authors:
Steven C Malvig; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| The objective of this research is to analyze the non-developing Tropical Circulation System (TCS025) utilizing data collected during the Tropical Cyclone Structure 2008 (TCS-08) and The Observing System Research and Predictability Experiment (THORPEX) Pacific Asian Regional Campaigns (T-PARC). Aircraft dropwindsondes, special ELDORA radar observations, and analyzed ECMWF model fields are used to define the three-dimensional structure at key times during the lifecycle of TCS025. Two TCS025-related Mesoscale Convective Systems (MCSs) ... |
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| Displacement of Tethered Hydro-Acoustic Modems by Uniform Horizontal Currents |
Dec 2009 |
73 pages |
| Authors:
Scott R Thompson; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF MECHANICAL AND ASTRONAUTICAL ENGINEERING
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| Undersea sensors often include an acoustic modem buoyed above a seabed mooring or suspended beneath a surface buoy. In both cases, a vertical cable is subjected to horizontal water currents. This thesis examines the two cases, the first characterized by a cable moored to the bottom of the ocean with a buoyant end, and the second being a cable suspended or towed from a surface buoy or Unmanned Surface Vehicle ... |
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| An Experimental Study of Fluid Structure Interaction of Carbon Composites under Low Velocity Impact |
Dec 2009 |
65 pages |
| Authors:
Angela C Owens; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF MECHANICAL AND ASTRONAUTICAL ENGINEERING
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| The effect of fluid force on the natural frequencies and damping ratios of vibrating structures in contact with fluid is known as the Fluid Structure Interaction (FSI) problem. It can be interpreted as an added mass to the vibrating structure in the analysis of the dynamic response. Because the density of water is much greater than air, the added mass effect becomes even more critical in understanding the dynamic response ... |
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| Initiation Mechanisms of Low-loss Swept-ramp Obstacles for Deflagration to Detonation Transition in Pulse Detonation Combustors |
Dec 2009 |
112 pages |
| Authors:
Myers; Charles B IV; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| In order to enhance the performance of pulse detonation combustors (PDCs), an efficient deflagration-to-detonation transition (DDT) process is critical to maintain the thermodynamic benefits of detonation-based combustion systems and enable their use as future propulsion or power generation systems. The DDT process results in the generation of detonation and can occur independently, but the required length is excessive in many applications and also limits the frequency of repeatability. Historically, obstacles ... |
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| Atlas of Deep Current Observations for Central California |
Dec 2009 |
293 pages |
| Authors:
Ulysses D Zamora; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF OCEANOGRAPHY
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| Deep (1000 m) currents were observed off California from August 1994 to September 2009 using current meters and RAFOS floats. Current meter data were collected at nine locations for time periods ranging from two months to 76 months. A total of 144 months of float data were collected. Analysis of current meter data included histograms, progressive vector diagrams, stick plots, kinetic energy and rotary spectra, stick plots, means and standard ... |
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| Aerodynamics Characteristics of Butterfly Flight Through Measurement of Three-Dimensional Unsteady Velocity Field Using TR-PIV System |
19-Nov-2009 |
43 pages |
| Authors:
Debopam Das; INDIAN INST OF TECH KANPUR
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| This report investigates understanding insect flight (having flapping and feathering motion) in view of lift & thrust generation, essential for flight control, with simultaneous measurement of velocity and forces. The present work is divided into two major portions. One being the flow visualization and PIV measurements, the other is force measurement. |
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| Parameterizing Internal Wave Boundary Mixing in a Canyon |
11-Nov-2009 |
9 pages |
| Authors:
Eric Kunze; James B Girton; WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB
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| This project, in collaboration with Eric Kunze at the University of Victoria, aimed to increase our understanding of (primarily tidal) internal wave processes and how they affect diapycnal mixing in the coastal ocean, with an eventual goal of improved representation of baroclinic tides and mixing parameterizations in numerical models. Our work is expected to add significantly to the knowledge of the internal wave field, its interactions with topography, and implications ... |
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| CROSSTEX - Wave Breaking, Boundary Layer Processes, the Resulting Sediment Transport and Beach Profile Evolution |
04-Nov-2009 |
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| Authors:
Tian-Jian Hsu; John Trowbridge; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA DEPT OF APPLIED OCEAN PHYSICS AND ENGINEERING
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| The proposal for this project was submitted from WHOI to ONR by Tom Hsu under John Trowbridge's sponsorship while Hsu was a post-doc at WHOI. WHOI continued to administer the project when Tom Hsu left WHOI, but virtually all of the work was done by Hsu, and virtually all of the funding was spent by Hsu in his new positions at the Universities of Florida and Delaware. Hsu's October 2009 ... |
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| Experimental and Numerical Study of Spread and Sorption of VX Sessile Droplets into Medium Grain-Size Sand |
02 Nov 2009 |
7 pages |
| Authors:
Terrence G D'Onofrio; Homayun K Navaz; Bojan Markicevic; Brent A Mantooth; Kenneth B Sumpter; EDGEWOOD CHEMICAL BIOLOGICAL CENTER ABERDEEN PROVING GROUND MD
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| The experimental measurement and modeling of liquid chemical agent spread and sorption on a porous substrate are described. Experimental results with the nerve agent O-ethyl S-(2-diisopropylaminoethyl) methylphosphonothiolate (VX) demonstrate that the wetted imprint volume increases, even after the sessile drop volume is exhausted. This indicates the wetted imprint is only partially saturated, and a multiphase flow problem formulation is needed to predict the VX fate in porous substrates. Three characteristics ... |
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| On the Impact of Injection Schemes on Transition in Hypersonic Boundary Layers |
13-Oct-2009 |
12 pages |
| Authors:
Ivett A Leyva; Stuart Laurence; Hans G Hornung; Joseph S Jewell; Joe Shepherd; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
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| Three geometries are explored for injecting CO2 into the boundary layer of a sharp five degree half-angle cone. The impact of the injection geometry, namely discrete injection holes or a porous conical section, on tripping the boundary layer is examined, both with and without injected flow. The experiments are conducted at Caltech's T5 reflected shock tunnel. Two different air free-stream conditions are explored. For the discrete-hole injectors, the diameter for ... |
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| Development of a Relocatable Coastal Forecast System - Korean Coast Application |
09-Oct-2009 |
9 pages |
| Authors:
Cheryl A Blain; Yifei P Chu; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
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| The goal is to fulfill the US Navy's need for a relocatable, robust operational coastal forecast system by developing and transitioning a high-resolution, coastal circulation model into the Naval Oceanographic Office's operational environment. The coastal circulation model undergoing transition is a three-dimensional, finite-element based hydrodynamic model, the Advanced Circulation Model for Shelves, Coastal Seas, and Estuaries (ADCIRC). Its unstructured grid allows modeling complex coastal regions at fine spatial scale. Scripts ... |
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| Assessment of BGK Approaches to Modeling of Nozzle Flows (PREPRINT) |
07 Oct 2009 |
28 pages |
| Authors:
Rakesh Kumar; E V Titov; D A Levin; N E Gimelshein; S F Gimelshein; AIR FORCE RESEARCH LAB EDWARDS AFB CA
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| Accurate and numerically efficient modeling of low to moderate Reynolds number nozzle flow expansions to vacuum can be difficult due to the presence of multiple flow length scales. Such simulations are important for the prediction of propulsive thrust as well as spacecraft contamination, both of which can be difficult to measure in ground based facilities. To that end, conical nozzle flows were studied for Reynolds numbers of 1,230 and 12,300 ... |
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| Lines of Energy Deposition for Supersonic/Hypersonic Temperature/ Drag-Reduction and Vehicle Control |
06-Oct-2009 |
15 pages |
| Authors:
Michael P Reilly; George H Miley; Kevin Kremeyer; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
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| Lines of energy are deposited ahead of supersonic and hypersonic vehicles in order to create a low-density channel, through which a vehicle can travel with dramatically reduced drag. Temperature and pressure are both also reduced on the front surfaces of the vehicle, while density and pressure are increased at the vehicle base. When applied off-center, this technique can be used to control the vehicle, employing the entire body as the ... |
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| Nozzles for Focusing Aerosol Particles |
Oct-2009 |
22 pages |
| Authors:
Yong-Le Pan; Steven C Hill; Richard K Chang; John Bowersett; Ronald G Pinnick; ARMY RESEARCH LAB ADELPHI MD COMPUTATIONAL AND INFORMATION SCIENCES DIRECTORATE
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| We report on the design, fabrication, and testing of nozzles that we have used for single-particle sampling measurements of laser-induced fluorescence and two-dimensional angular optical scattering. Single-piece nozzles and a two-piece nozzle with a sheath flow are described. |
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| Boundary Layer Turbulence (BLT) Water Vapor Measurement Test: Summary of Current Results, September 2009 |
Oct-2009 |
38 pages |
| Authors:
Sean O'Brien; David Quintis; Robert Brice; David Tofsted; Jimmy Yarbrough; D S Elliott; ARMY RESEARCH LAB WHITE SANDS MISSILE RANGE NM COMPUTATIONAL AND INFORMATION SCIENCE DIRECTORATE
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| The propagation of terahertz (THz) band radiation through the atmosphere is a topic of increasing interest as advanced passive and active imaging systems are developed that operate in this spectral region. Much of the impact of the boundary layer atmosphere in this band is due to water vapor absorption, which is very strong even in atmospheric window regions. Most of the effect of atmospheric water vapor is due to the ... |
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| Development of a Versatile Conditioning Wind Tunnel for Evaporative Fate Studies |
Oct-2009 |
63 pages |
| Authors:
H D Durst; James E Danberg; Daniel J Weber; Daniel Waysbort; Clayton S Moury; EDGEWOOD CHEMICAL BIOLOGICAL CENTER ABERDEEN PROVING GROUND MD
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| This report documents the development of a conditioning wind tunnel that allows multiple test samples to be conditioned at identical environmental settings that are used in smaller vapor sampling wind tunnels. The conditioning of multiple samples, especially those involving persistent chemicals, allows for the efficient use of a limited number of instrumented vapor sampling tunnels. Up to nine samples can be sequentially and quickly cycled through the instrumented vapor wind ... |
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| Diagnostics of Flow Suppression on Rotor Blades: Final Report |
30-Sep-2009 |
37 pages |
| Authors:
James DiOttavio; Narayanan M Komerath; Vrishank Raghav; GEORGIA INST OF TECH ATLANTA OFFICE OF SPONSORED RESEARCH
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| In a 4-year project, the radial flow phenomena in the stalled region of rotor blades typical of retreating-blade stall were investigated. First a partial inflow obstructor was devised in order to create transient flow separation on a rotor blade in a hover facility. Next, a 2-bladed teetering rotor rig was designed, built and operated at high advance ratios appropriate for dynamic stall, in the John Harper Low Speed Wind Tunnel ... |
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| Signal Modeling of Turbulence-Distorted Imagery |
Sep-2009 |
18 pages |
| Authors:
S S Young; Ron Driggers; Keith Krapels; Richard Espinola; Joseph Reynolds; Jae Cha; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
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| Understanding turbulence effects on wave propagation and imaging systems has been an active research area for more than 50 years. Conventional atmospheric optics methods use statistical models to analyze image degradation effects that are caused by turbulence. In this paper, we intend to understand atmospheric turbulence effects using a deterministic signal processing and imaging theory point of view and modeling. The model simulates the formed imagery by a lens by ... |
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| Numerical Study of Effects of Fluid-Structure Interaction on Dynamic Responses of Composite Plates |
Sep-2009 |
115 pages |
| Authors:
Peter K Kendall; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| Composite materials are seeing increased use in structural applications because of their various benefits. When composite structures are employed in a water environment, their dynamic responses are greatly affected by the fluid medium. Water density is comparable to many composite materials and the effects of fluid-structure interaction on dynamic behaviors of composite structures are significant. The effects of fluid-structure interaction include changes of frequency, magnitude, energy dissipation, etc., of structural ... |
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| Slope/Shelf Circulation and Cross-Slope/Shelf Transport Out of a Bay Driven by Eddies from the Open Ocean |
Sep-2009 |
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| Authors:
Yu Zhang; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
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| Interaction between the Antarctic Circumpolar Current and the continental slope/shelf in the Marguerite Bay and west Antarctic Peninsula is examined as interaction between a wind-driven channel flow and a zonally uniform slope with a bay-shaped shelf to the south. Two control mechanisms, eddy advection and propagation of topographic waves, are found important for eddy topography interactions. The topographic waves become more nonlinear near the western (eastern if in the Northern ... |
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| CFD Prediction of Magnus Effect in Subsonic to Supersonic Flight |
Sep-2009 |
46 pages |
| Authors:
James DeSpirito; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The aerodynamic coefficients of the 7-cal. U.S. Army-Navy Spinner Rocket were characterized using computational fluid dynamic (CFD) calculations and validated using archival experimental data. The static aerodynamic coefficients, roll-damping, and pitch-damping moments were accurately predicted by steady-state Reynolds-averaged Navier-Stokes (RANS) as well as unsteady hybrid RANS/large-eddy simulation (LES) CFD. The Magnus moment was overpredicted in the subsonic and transonic regime. Unsteady RANS/LES computations did not improve the prediction of Magnus ... |
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| High-Resolution Global and Basin-Scale Ocean Analyses and Forecasts |
Sep-2009 |
19 pages |
| Authors:
Eric P Chassignet; Hiroyuki Tsujino; Benoit Tranchant; Andreas Schiller; Timothy F Pugh; Peter R Oke; Jean-Michel Lellouche; Olivier Galloudec; Gregg A Le Jacobs; Romain Bourdalle-Badie; Mounir Benkiran; Masafumi Kamachi; Yann Drillet; Gary B Brassington; Alan J Wallcraft; E J Metzger; Ole M Smedstad; Harley E Hurlburt; Norihisa Usui; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS OCEAN DYNAMICS AND PREDICTION BRANCH
|
| The feasibility of global ocean weather prediction was just emerging as the Global Ocean Data Assimilation Experiment (GODAE) began in 1997. Ocean weather includes phenomena such as meandering currents and fronts, the surface mixed layer and sea surface temperature (SST), waves, upwelling of cold water, all influencing ocean variables such as temperature (T), salinity (S), currents, and sea surface height (SSH). Adequate real-time data input, computing power, numerical ocean models, ... |
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| Improving and Increasing the Efficiency of the P-8A Test Work Description (TWD) Process |
Sep-2009 |
86 pages |
| Authors:
McDermott; James W Jr; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| This study's purpose was to identify opportunities to improve the P-8A test working description (TWD) process in support of the P-8A test program. This study researched other NAVAIR test programs that used a contractor and government integrated test approach. This study determined the proper balance of improvements to support the approval of TWDs to keep pace with the testing. The process was functionally decomposed to look for process redundancies, choke ... |
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| Steady and Unsteady Aerodynamic Flow Studies Over a UCAV 1303 Configuration |
Sep-2009 |
77 pages |
| Authors:
Brian K McLain; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| This study generated new information through qualitative documentation of the main flow features and direct measurements of the aerodynamic performance of a tailless, unmanned combat air vehicle (UCAV) 1303 configuration under both steady and unsteady maneuvering conditions. Photographic evidence of flow features, measurements of large-scale flow effects, and that of forces and aerodynamic coefficients during static and dynamic pitch, roll and yaw maneuvers were obtained. Flow visualization images and force ... |
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| Scaling Effects on Stern Flap Performance. Progress Report |
Sep-2009 |
55 pages |
| Authors:
Dominic S Cusanelli; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD HYDROMECHANICS DIRECTORATE
|
| The installation of a prototype stern flap on the USS RAMAGE (DDG 61), the 11th destroyer of the DDG 51 Class, with associated stern flap evaluation trials, has provided invaluable information towards the continuation of the stern flap scale effects investigation. Comparison of stern flap trials results on RAMAGE, to that of a geosim model experiment series, was utilized for the refinement of techniques for extrapolation of model test data ... |
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| Investigation of Performance Improvements Including Application of Inlet Guide Vanes to a Cross-flow Fan |
Sep-2009 |
117 pages |
| Authors:
Samuel F Cordero; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The inherent characteristics of a cross-flow fan allowing for easy thrust vectoring as well as potential airfoil boundary layer control make it an attractive propulsive means for a theoretical vertical takeoff and landing aircraft. However, to compete with current methods of aircraft propulsion, further performance improvements of the cross-flow fan are needed. A baseline model of a cross-flow fan geometry developed by Vought Systems in the 1970s was scaled from ... |
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| Concepts for Functional Restoration of Barrier Islands |
Sep-2009 |
15 pages |
| Authors:
Julie D Rosati; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS ENVIRONMENTAL LAB
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| This Coastal and Hydraulics Engineering Technical Note (CHETN) presents guidance for functional restoration of barrier islands. The concept of functional restoration is introduced here as an engineering and ecological design such that a barrier island can perform as a wave attenuator, storm surge buffer, and ocean boundary for an estuary, bay, and mainland over the defined project lifetime. Ecological design is required as part of the restoration to minimize initial ... |
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| Numerical Model Study of the Tuscarawas River below Dover Dam, Ohio |
Sep-2009 |
58 pages |
| Authors:
Richard L Stockstill; Jane M Vaughan; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS COASTAL AND HYDRAULICS LAB
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| The U.S. Army Corps of Engineers, Huntington District (LRH) has been charged with upgrading Dover Dam to meet hydrologic design standards and address stability issues. The LRH requested that the U. S. Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory (CHL), evaluate the flow conditions in the Tuscarawas River downstream of Dover Dam as part of a safety assurance program. The two-dimensional depth-averaged module of the Adaptive Hydraulics ... |
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| J. T. Myers Landside Lock Outlet Diffuser Study, Ohio River |
Sep-2009 |
41 pages |
| Authors:
Hite; John E Jr; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS COASTAL AND HYDRAULICS LAB
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| Navigation improvements are planned at J. T. Myers Locks and Dam on the Ohio River main stem. The existing project consists of a navigation dam, a 1,200-ft-long by 110-ft-wide main lock chamber adjacent to a 600-ft-long by 110-ft-wide auxiliary lock chamber. One of the improvements includes developing a 1,200-ft long lock chamber from the existing 600-ft-long lock chamber. The outlet design originally proposed for the filling and emptying system in ... |
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| Modeling of the 105-mm Rarefaction Wave Gun |
Aug-2009 |
36 pages |
| Authors:
Terrence P Coffee; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| The Rarefaction wAVE guN (RAVEN) is designed to reduce the recoil momentum of a gun while having a minimal effect on the projectile velocity. The recoil reduction is achieved by venting gas out the breech through an expansion nozzle. This is similar to a recoilless rifle. The difference is that the venting is delayed until the projectile is some distance down tube. The opening of the breech creates a rarefaction ... |
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Fluid Mechanics
