| Development of a Four-Fin Bio-Inspired UUV: CFD Studies |
04 Sep 2012 |
39 pages |
| Authors:
Ravi Ramamurti; Jason D Geder; NAVAL RESEARCH LAB WASHINGTON DC LAB FOR COMPUTATIONAL PHYSICS AND FLUID DYNAMICS
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 | The development of an unmanned underwater vehicle (UUV) with four actively controlled curvature flapping fins is described. Three dimensional unsteady flow computations past several configurations of the vehicle are computed and based on the minimum drag a nearly elliptical cross-section with a smooth leading and trailing sections was obtained. The hydrodynamic characteristics of this vehicle at NRL are computed for a range of operational conditions and a dynamic mode of ... |
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| Scaling Study of Wave Rotor Turbo-normalization of a Small Internal Combustion Engine |
Sep 2012 |
113 pages |
| Authors:
Brandon D Smith; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| One issue facing small Remotely Piloted Aircraft engines is their ability to maintain performance at altitude. Since many of these aircraft use commercial off the shelf engines originally designed for radio controlled aircraft and lawn care implements, the reduced pressure environment significantly degrades the operability of the engine as the altitude increases. An option to overcome this difficulty is to supercharge the system; however most superchargers are designed for larger, ... |
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| Viability of Cross-Flow Fan with Helical Blades for Vertical Take-off and Landing Aircraft |
Sep 2012 |
70 pages |
| Authors:
Howe L Kwek; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF MECHANICAL AND AEROSPACE ENGINEERING
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| The cross-flow fan (CFF) is a lifting and propulsion device that retains the advantages of a fixed-wing aircraft by using a ducted lift fan. There is no upper limit to the rotor length-to-diameter ratio of a CFF, allowing the device to be installed along the length of the wing or lifting device. The CFF discharged vector can be easily rotated about the fan axis since the fan has no angular ... |
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| CFD Transient Simulation of an Isolator Shock Train in a Scramjet Engine |
Sep 2012 |
221 pages |
| Authors:
Troy C Hoeger; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| For hypersonic flight, the scramjet engine uses an isolator to contain the pre-combustion shock train formed by the pressure difference between the inlet and the combustion chamber. If this shock train were to reach the inlet, it would cause an engine unstart, disrupting the flow through the engine and leading to a loss of thrust and potential loss of the vehicle. Prior to this work, a Computational Fluid Dynamics (CFD) ... |
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| Genetic Algorithm Optimization of a Film Cooling Array on a Modern Turbine Inlet Vane |
Sep 2012 |
374 pages |
| Authors:
Jamie J Johnson; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
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| In response to the need for more advanced gas turbine cooling design methods that factor in the 3-D flowfield and heat transfer characteristics, this study involves the computational optimization of a pressure side film cooling array on a modern turbine inlet vane. Latin hypersquare sampling, genetic algorithm reproduction, and Reynolds-Averaged Navier Stokes (RANS) computational fluid dynamics (CFD) as an evaluation step are used to assess a total of 1,800 film ... |
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| ROTATESTL: A MATLAB Rotation Algorithm for the Analysis of Computational Meshes in Stereolithography File Format |
Sep 2012 |
70 pages |
| Authors:
James A Tancred; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AEROSPACE SYSTEMS DIR
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| With the continued increase in power of the modern computer, more computational problems are tractable via computer simulation, leading to fast production of data, analysis, and quantitative solutions. Discrete three dimensional analyses, including those involving computational fluid dynamics, now show even more promise as the time required to meet solutions has been shown, in some instances, to be on the order of hours and days rather than weeks or months ... |
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| Computational Fluid Dynamics Co-processing for Unsteady Visualization |
Sep 2012 |
19 pages |
| Authors:
Andrew Bauer; Berk Geveci; KITWARE INC CLIFTON PARK NY
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| With the ever growing computational power available on the largest parallel machines, the ability to generate CFD simulation data is outpacing the ability to analyze and visualize it. This is due to the large disparity between the computational facilities (up to hundreds of thousands of cores) and the typical personal computer or visualization cluster. This project's goal was to begin the analysis and visualization of these large data sets on ... |
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| Development of High-Order Method for Multi-Physics Problems Governed by Hyperbolic Equations |
01 Aug 2012 |
41 pages |
| Authors:
John A Ekaterinarius; FOUNDATION FOR RESEARCH AND TECHNOLOGY-HELLAS HERAKLION CRETE (GREECE)
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| In this section we present the discontinuous Galerkin (DG) discretization of the three dimensional Euler and Nervier-Stokes equations for hybrid-type meshes. Without loss of generality the general finite element discretization framework is presented for hexahedral type meshes since all computations of the DG method are performed at the computational domain on the standard cubic element and transferred back to the physical domain elements (tetrahedras, prisms, pyramids, or hexahedras) using collapsed ... |
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| High-Accuracy Methods for Numerical Flow Analysis Using Adaptive Non-Linear Wavelets |
01 Aug 2012 |
81 pages |
| Authors:
Dohyung Lee; HANYANG UNIV AT ANSAN (KOREA)
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| Nonlinear adaptive wavelets are developed for compact data representation and efficient flow solution algorithms. To flow solution algorithms, proposed new adaptive wavelets enhance the computational efficiency as well as preserve the numerical accuracy in steady and unsteady flow computations. These advantageous features of the wavelet are confirmed by the numerical tests of two-dimensional airfoil problem and unsteady shock-vortex interaction problem. An adaptive wavelet method with higher order of accuracy is ... |
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| Software Design Strategies for Multidisciplinary Computational Fluid Dynamics |
Jul 2012 |
16 pages |
| Authors:
Roger C Strawn; ARMY AVIATION AND MISSILE RESEARCH DEVELOPMENT AND ENG CTR MOFFETT FIELD CA AEROFLIGHTDYNAMICS DIRECTORATE
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| The multidisciplinary nature of rotary-wing aeromechanics poses a daunting challenge for the design of practical modeling and simulation software that is accurate, efficient, and maintainable. This paper describes the design strategy for the US Army's Helios software, which features a lightweight Python-language integration framework combined with well-defined interfaces to link together various multidisciplinary software components. This design facilitates the use of alternative component software within Helios, the addition of new ... |
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| Development of a MEMS-Scale Turbomachinery Based Vacuum Pump |
Jun 2012 |
115 pages |
| Authors:
Michael J Shea; AMERICAN MOUNT EVEREST EXPEDITION INC SANTA MONICA CA
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| This study forms part of a larger study to develop a MEMS scale turbomachinery based vacuum pump. This would allow very high vacuum to be drawn for handheld mass spectroscopy. This thesis concentrates on the roughing portion of the turbo pump where flow can still be treated as a continuum but the no slip boundary condition is not accurate. The first portion of this thesis investigates flow at Knudsen numbers ... |
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| Ground Vehicle CFD at TARDEC |
21 May 2012 |
25 pages |
| Authors:
Robert E Smith; ARMY TANK AUTOMOTIVE RESEARCH DEVELOPMENT AND ENGINEERING CENTER WARREN MI
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| Simulation of Distortion Generation in a Modern Serpentine Diffuser to Improve Experimental Effectiveness (Preprint) |
16 May 2012 |
11 pages |
| Authors:
Darius D Sanders; Michael G List; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIR/TURBINE ENGINE DIV/FAN AND COMPRESSOR BRANCH
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| Modern serpentine diffusers create distorted flowfields which are ingested by embedded propulsion systems. Fundamental research into the generation and content of such distortion patterns is necessary to better understand inlet conditions for the engine. Simulation of the diffuser provided a number of insights for a complementary experimental program including particle image velocity (PIV) plane placement and seeding locations, necessary resolution of measurement, and expected operational range and conditions. Analysis of ... |
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| Use of Forward Scattering Particle Image Velocimetry to Quantify a Flow Field Near a Fully Submerged Tension Leg Platform in the Presence of Waves |
May 2012 |
22 pages |
| Authors:
Michael Raftery; STEVENS INST OF TECHNOLOGY HOBOKEN NJ
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| Fully Submerged platforms have the potential to provide the US navy with marine renewable energy systems that could be deployable throughout the world's oceans, avoid extreme mooring loads in storms and focus surface wave energy onto power take-off components in mild wave conditions. The deployment process being developed for a full scale design is particularly well suited for littoral regions with silt or sand sea floors. A variable depth platform ... |
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| Computational Fluids Domain Reduction to a Simplified Fluid Network |
19 Apr 2012 |
186 pages |
| Authors:
Robert E Smith; ARMY TANK AUTOMOTIVE RESEARCH DEVELOPMENT AND ENGINEERING CENTER WARREN MI
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| The primary goal of this project is to demonstrate the practical use of data mining algorithms to cluster a solved steady-state computational fluids simulation (CFD) flow domain into a simplified lumped-parameter network. A commercial-quality code, cfdMine was created using a volume-weighted k-means clustering that that can accomplish the clustering of a 20 million cell CFD domain on a single CPU in several hours or less. Additionally agglomeration and k-means Mahalanobis ... |
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| Computational Fluids Domain Reduction to a Simplified Fluid Network |
19 Apr 2012 |
82 pages |
| Authors:
Robert E Smith; ARMY TANK AUTOMOTIVE RESEARCH DEVELOPMENT AND ENGINEERING CENTER WARREN MI
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| High Order Accurate Weighted Essentially Non-oscillatory Algorithms for Shock Calculations |
02 Apr 2012 |
6 pages |
| Authors:
Chi-Wang Shu; BROWN UNIV PROVIDENCE RI DIV OF APPLIED MATHEMATICS
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| We have performed research on the algorithm development, analysis, implementation and application for high order weighted essentially non-oscillatory (WENO) finite difference and finite volume schemes and related methods, for solving computational fluid dynamics (CFD) problems and other applications containing strong shock waves and complicated smooth region structures. The goal of this research is to help obtaining more robust, cost effective, and reliable numerical tools for computational fluid dynamics problems and ... |
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| Accurate Modeling of Stability and Control Properties for Fighter Aircraft from CFD |
Mar 2012 |
196 pages |
| Authors:
Jedediah H Butler; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
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| Difficulties in obtaining accurate Stability and Control (S&C) data for nonlinear regions in the flight envelope early in the design phase often lead to costly fixes late in the acquisition process. Work examined herein addresses this problem by utilizing recent advances in Computational Fluid Dynamics (CFD) to create a high-fidelity database before any parts have to be physically produced. In combination with CFD, System Identification (SID) is used to characterize ... |
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| Cyber-Based Turbulent Combustion Simulation |
28 Feb 2012 |
10 pages |
| Authors:
Joseph J Shang; WRIGHT STATE UNIV DAYTON OH DEPT OF MECHANICAL AND MATERIALS ENGINEERING
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| In an attempt to develop a viable option for complex turbulent combustion research, the flamelet concept is investigated by developing an interdisciplinary modeling and simulation capability via local grid refinement technique. The inherent deficiency at the grid block interface of the local polynomial refinement approach using the Gauss Quadrature formulation is remedied by a differential reconstruction scheme. The symmetry, coercivity, boundness, and adjoint consistency conditions of solutions at the grid ... |
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| A Gas-Surface Interaction Model based on Accelerated Reactive Molecular Dynamics for Hypersonic Conditions including Thermal Conduction |
28 Feb 2012 |
30 pages |
| Authors:
Thomas E Schwartzentruber; Ellad B Tadmor; Ioana Cozmuta; MINNESOTA UNIV MINNEAPOLIS DEPT OF AEROSPACE ENGINEERING AND MECHANICS
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| Vehicles traveling through an atmosphere at hypersonic speeds generate strong shock waves. These shock waves generate extremely high gas temperatures within the shock layer between the shock itself and the surface of the vehicle. As the gas reaches such high temperatures, its vibrational degrees of freedom become excited and diatomic and polyatomic molecules dissociate into reactive atomic species. At high altitudes characteristic of hypersonic flight where the free-stream density is ... |
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| Numerical Modeling of Pulsed Electrical Discharges for High-Speed Flow Control |
Feb 2012 |
175 pages |
| Authors:
Jonathan Poggie; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AIR VEHICLES DIRECTORATE
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| This report describes work carried out on numerical modeling of flow control devices based on pulsed electrical discharges. Given the lack of flow control options in the high-speed regime, there is strong interest in developing such devices for control of laminar-turbulent transition, turbulence, engine unstart, and inlet shock train stability. Pulsed electrical discharge actuators offer the features of rapid actuation, low profile, and low mean power consumption. Under this project, ... |
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| Center of Excellence for Hypersonics Research |
25 Jan 2012 |
46 pages |
| Authors:
Graham V Candler; Krishnan Mahesh; Thomas Schwartzentruber; Michael Holden; Matthew MacLean; MINNESOTA UNIV MINNEAPOLIS DEPT OF AEROSPACE ENGINEERING AND MECHANICS
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| The Center of Excellence in Hypersonics Research was established to support future hypersonic vehicle development programs. The Center engaged leading experts in experimental and computational analysis of hypersonic flows to provide research, education, and technology development in hypersonics. The Center combined the world's premiere hypervelocity testing facility at the CUBRC with state-of-the-art computational simulation methods at the University of Minnesota to rapidly advance the field of hypersonics. The Center supported ... |
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| Fluid-Structure Interaction Evaluation of F-16 Limit Cycle Oscillations |
09 Jan 2012 |
11 pages |
| Authors:
Jason A Lechniak; Keerti K Bhamidipati; AIR FORCE FLIGHT TEST CENTER EDWARDS AFB CA
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| Application of high-fidelity computational science and engineering (CSE) tools provide better data for decisions to enhance weapon systems acquisition, testing, and support. Fluid structure interaction (FSI) simulation is being evaluated to quantify aero-structural dynamic mechanisms that bound F-16 limit cycle oscillations (LCO). The intent of the research objectives is to provide a better understanding of flight-test aero-structural observations through the utilization of CSE tools. Validation of results provided by CSE ... |
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| Computational Study of the Effect of Slot Orientation on Synthetic Jet-Based Separation Control |
Jan 2012 |
25 pages |
| Authors:
Shawn Aram; Rajat Mittal; JOHNS HOPKINS UNIV BALTIMORE MD DEPT OF MECHANICAL ENGINEERING
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| A computational study is conducted to explore the effect of synthetic jet orientation on boundary layer separation control. A six-to-one aspect-ratio rectangular slot is chosen in the current study and streamwise and spanwise orientations of this slot are analyzed. In the first part of this study, the interaction of the jet with an attached laminar boundary layer for both slot configurations is examined. The dominant feature in the streamwise oriented ... |
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| Development of Photographic Dynamic Measurements Applicable to Evaluation of Flapping Wing Micro Air Vehicles |
Dec 2011 |
86 pages |
| Authors:
Jeremy C Murray; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH DEPT OF AERONAUTICS AND ASTRONAUTICS
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| Developments in the area of flapping wing micro air vehicles (FWMAVs) of a small size and with limited range. This has lead to a great deal of interest in biomimetric designs based on flapping wing flyers, including the North American Hawkmoth (Manduca Sexta). By utilizing high speed photography and photogrammetry the dynamic flapping of the wing can be characterized for comparison with mathematical models, namely computational fluid dynamics (CFD) and ... |
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| Experimental Study of Fluid Structure Interaction Effects on Metal Plates Under Fully Developed Laminar Flow |
Dec 2011 |
87 pages |
| Authors:
Chee Chew Wong; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| The development of a reference test case with repeatable and accurate results is of paramount importance for the validation of numerical Fluid Structure Interaction (FSI) models and simulations. In this study, a new experimental facility was designed and constructed for the investigation of FSI between fully developed laminar flow and test section plate in an enclosed flow channel. Computational Fluid Dynamics (CFD) software was used to model laminar flow in ... |
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| Quasi-Transient Calculation of Surface Temperatures on a Reusable Booster System with High Angles of Attack |
Dec 2011 |
111 pages |
| Authors:
Seth H Morris; DAYTON UNIV OH
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| The calculation of a recovery temperature based heat transfer coefficient proves to be sufficiently independent of wall temperature to use in a three dimensional, transient temperature model of a thermal protection system of a reusable booster concept. After a derivation of recovery temperature from the 1st law of thermodynamics, the weak dependence of the recovery temperature based heat transfer coefficient is investigated by 72 Computational Fluid Dynamics (CFD) models at ... |
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| Aerodynamic Analysis of a Canard Missile Configuration using ANSYS-CFX |
Dec 2011 |
115 pages |
| Authors:
Hong C Wee; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| This study used the Computational Fluid Dynamics code, ANSYS-CFX to predict the static aerodynamic characteristics of a canard-wing missile configuration with a hemispherical nose, triangular wedge canards and fixed trapezoidal wings. The study was conducted for Mach numbers of 0.2, 0.8 and 1.2. The results were compared against experimental data from actual wind tunnel tests and data from a semi-empirical method, AP09. The ANSYS-CFX results showed good agreement for CN, ... |
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| Fluidically Augmented Nozzles for Pulse Detonation Engine Applications |
Dec 2011 |
147 pages |
| Authors:
Larry R Smith; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| Pulse Detonation Engines (PDE) operate in a cyclic manner resulting in large changes in the combustion chamber pressure. The widely varying pressure ratio between the chamber and nozzle exit makes it difficult to efficiently produce thrust since a fixed area ratio exhaust nozzle would operate off design nearly the entire cycle. Therefore, a nozzle with the capability to create the necessary area ratio throughout the cycle is required to produce ... |
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| Effects of Passive Porous Walls on the First Mode of Hypersonic Boundary Layers Over a Sharp Cone |
Dec 2011 |
54 pages |
| Authors:
Sharon O Stephen; BIRMINGHAM UNIV (UNITED KINGDOM)
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| A theoretical linear stability analysis is used to consider the effect of a porous wall on the first mode of a hypersonic boundary layer on a sharp slender cone. The effects of curvature and of the attached shock are included for axisymmetric and nonaxisymmetric disturbances. The flow in the hypersonic boundary layer is coupled to the flow in the porous layer. The linear results for neutral stability and spatial stability ... |
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| Assessment of Aerothermodynamic Flight Prediction Tools through Ground and Flight Experimentation (Evaluation des outils aerothermodynamiques de prediction de vol par l'experimentation au sol et en vol) |
Nov 2011 |
194 pages |
| Authors:
NATO RESEARCH AND TECHNOLOGY ORGANIZATION NEUILLY-SUR-SEINE (FRANCE)
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| AVT-136 was organized to assess and improve the understanding and prediction of aerothermodynamic phenomena and aerothermal loads for space transportation and earth/planetary entry systems through ground and flight experimentation. To achieve this goal, efforts were organized around six scientific topic areas: 1) Nose and Leading Edges; 2) Shock Interactions and Control Surfaces; 3) Shock Layers and Radiation; 4) Boundary Layer Transition; 5) Gas-Surface Interactions; and 6) Base and Afterbody Flows. ... |
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| TSA - a Two Scale Approximation for Wind-Generated Ocean Surface Waves |
30 Sep 2011 |
7 pages |
| Authors:
William Perrie; BEDFORD INST OF OCEANOGRAPHY DARTMOUTH (NOVA SCOTIA)
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| The rationale for this project is that nonlinear 4-wave interactions, represented by FBI (Full Boltzmann Integral) have been shown to be central to wave forecast models. However, these FBI formulations are too slow for operational wave forecasting. The discrete interaction approximation (DIA) is the basis for operational wave models WAM, and it has substantial deviations from FBI in selected parts of the spectrum. Two Scale Approximation (TSA) offers a new ... |
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| Analysis of Coaxial Injectors Using CFD++ |
12 Sep 2011 |
37 pages |
| Authors:
Henry Vu; ADVATECH PACIFIC INC SAN BERNARDINO CA
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| This is a presentation to the Metacomp Users Group meeting in Long Beach, CA, about analyzing coaxial injectors using CFD++. |
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| Investigation of Transitional Flows on Compressor Blades in Cascade |
Sep 2011 |
111 pages |
| Authors:
Michael L Holihan; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| Flow around polished second-generation controlled-diffusion blades in cascade set at their design inlet flow angle was investigated at various Reynolds numbers using static pressure measurements, five-hole probe surveys, twocomponent laser Doppler velocimetry (LDV), computational fluid dynamics and flow visualization. A suction-side separation bubble formed at Reynolds number, based on chord length, of 203,000 and collapsed by a Reynolds number of 393,000. Five-hole probe surveys characterized the blade-row inlet and outlet ... |
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| The Challenges of Comparing Propulsion Cooling CFD Studies to Test Chamber and On-Road Performance |
AUG 2011 |
9 pages |
| Authors:
Scott Shurin; Vamshi M. Korivi; ARMY TANK AUTOMOTIVE RESEARCH DEVELOPMENT AND ENGINEERING CENTER WARREN MI
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| The thermal test chambers available at TARDEC for validation and development testing are different in terms of capability, size, and flow setup. The effects of the chamber setup on propulsion cooling airflow and the challenges of using thermal chamber tests to correlate CFD results and predict off-road performance will be discussed. Numerical simulation and test results for both a tracked combat vehicle tested in a large test cell and a ... |
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| Numerical Schemes and Computational Studies for Dynamically Orthogonal Equations (Multidisciplinary Simulation, Estimation, and Assimilation Systems: Reports in Ocean Science and Engineering) |
Aug 2011 |
49 pages |
| Authors:
Mattheus P Ueckermann; Pierre F Lermusiaux; Themis P Sapsis; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF MECHANICAL ENGINEERING
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| The quantification of uncertainties is critical when systems are nonlinear and have uncertain terms in their governing equations or are constrained by limited knowledge of initial and boundary conditions. Such situations are common in multiscale, intermittent and non-homogeneous fluid and ocean flows. The Dynamically Orthogonal (DO) field equations provide an efficient time-dependent adaptive methodology to predict the probability density functions of such dynamics. This work derives efficient computational schemes for ... |
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| Challenges of Comparing Propulsion Cooling CFD to Test Chamber and Off-Road Performance |
20 JUL 2011 |
17 pages |
| Authors:
Scott Shurin; ARMY TANK AUTOMOTIVE RESEARCH DEVELOPMENT AND ENGINEERING CENTER WARREN MI
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| Can Wing Tip Vortices Be Accurately Simulated? |
JUL 2011 |
14 pages |
| Authors:
Ryan Termath; Jason Lechniak; Keerti Bhamidipati; AIR FORCE FLIGHT TEST CENTER EDWARDS AFB CA
|
| Modeling and Simulation (M&S) computational fluid dynamics (CFD) techniques were used to better understand wing tip vortices about a wing section. The CFD results were compared to experimental wind tunnel data derived from the University of Iowa (Ref. 2). The experiment used Stereoscopic Particle Image Velocimetry (SPIV) to measure the flow field. The SPIV data from the experiment illustrates the vortex core development and behavior downstream of the trailing edge ... |
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| Can Wing Tip Vortices Be Accurately Simulated? |
Jul 2011 |
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| Authors:
Ryan Termath; Jason Lechniak; Keerti Bhamidipati; AIR FORCE FLIGHT TEST CENTER EDWARDS AFB CA
|
| Modeling and Simulation (M&S) computational fluid dynamics (CFD) techniques were used to better understand wing tip vortices about a wing section. The CFD results were compared to experimental wind tunnel data derived from the University of Iowa (Ref. 2). The experiment used Stereoscopic Particle Image Velocimetry (SPIV) to measure the flow field. The SPIV data from the experiment illustrates the vortex core development and behavior downstream of the trailing edge ... |
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| Flow Characteristics and Status of CFD Hydrodynamic Model Development in Sudden Contraction Manifold/Orifice Configurations |
Jul 2011 |
85 pages |
| Authors:
W H Nurick; NURICK AND ASSOCIATES CAMARILLO CA
|
| Applications of sudden contraction manifold/orifice configurations range from city water drainage, diesel and gasoline fuel injection systems, and high speed underwater torpedoes, as well as rocket engine injector manifold flow passages. While the literature is extensive and dates back more than a century, the details of the flow characteristics as well as the quantitative impacts on losses are still sketchy at best. A clear understanding of the detailed process flow ... |
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| Study of Varying Boundary Layer Height on Turret Flow Structures |
JUN 2011 |
119 pages |
| Authors:
Renato Jelic; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH DEPT OF AERONAUTICS AND ASTRONAUTICS
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| The Air Force Institute of Technology and the Air Force Research Labs are investigating flows over turrets which are commonly encountered in directed energy integrations with air vehicles. In this work, the computational study was performed using the NASA developed time-marching finite volume code OVERFLOW 2.2 to analyze the effect of boundary layer height on symmetrical and non-symmetrical turret geometries. The effects of aerodynamics yield to the aberration of the ... |
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| Design and Evaluation of a Single-Inlet Pulse Detonation Combustor |
JUN 2011 |
89 pages |
| Authors:
Danny Soria; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Pulse detonation combustion offers thermodynamic advantages to the next generation of combustion systems. The thermodynamic efficiency is substantially improved over constant-pressure combustion systems by utilizing detonation-based combustion that occurs typically between 40 and 60 pulses per second. An existing four-inlet combustor was modified to a single-inlet arm design for integration with a rotary-valve concept. This paper discusses the design process of the single-inlet combustor so that it provides the same ... |
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| A Neural-Network Model-Based Engineering Tool for Blast Wall Protection of Structures (Postprint) |
Jun 2011 |
21 pages |
| Authors:
Bryan T Bewick; Ian Flood; Zhen Chen; FLORIDA UNIV GAINESVILLE COLL OF DESIGN CONSTRUCTION & PLANNING / RINKER SCHOOL OF BUILDING CONSTRUCTION
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| Blast barrier walls have been shown to reduce blast loads on structures, especially in urban environments. Analysis of existing test and simulation data for blast barrier response has revealed that a need still exists to determine the bounds of the problem and produce a fast-running accurate model for the effects of barrier walls on blast wave propagation. Since blast experiments are very time intensive and extremely cost prohibitive, it is ... |
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| Computational Fluid Dynamics Study for a Deep Stall Air Vehicle |
31 MAY 2011 |
21 pages |
| Authors:
Ravi Ramamurti; NAVAL RESEARCH LAB WASHINGTON DC CENTER FOR REACTIVE FLOW AND DYNAMICAL SYSTEMS
|
| The aerodynamic characteristics of a vehicle in deep-stall conditions are investigated and the motion of the vehicle is predicted in a self-consistent manner. Three-dimensional unsteady computations of the complete aircraft with prescribed control surface deflections are carried out. Both steady and unsteady flow simulations are performed to map out the lift, drag, and moment as a function of various flight and control surface parameters. The unsteady forces and moments were ... |
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| Numerical Investigation of a Low Aspect Ratio Flat Plate |
19 May 2011 |
18 pages |
| Authors:
Yongsheng Lian; LOUISVILLE UNIV KY
|
| This report presents the key findings resulting from an AFOSR grant. In this reseasrch we extended our previous results on the linear pitch-ramp-return of a two-dimensional (2D) flat plate to that of a three-dimensional (3D) flat plate of various aspect ratios, in an attempt to quantify 3D effects and the boundary effects on flapping wing aerodynamics. Specifically we compared the leading edge vortex (LEV) between the two-2D and the corresponding ... |
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| ALREST High Fidelity Modeling Program Approach |
18 May 2011 |
24 pages |
| Authors:
Edward D Lynch; Brian Lariviere; Douglas G Talley; Suresh Menon; PRATT AND WHITNEY ROCKETDYNE CANOGA PARK CA
|
| The U.S. Air Force Research Laboratory (AFRL) is working with Pratt & Whitney Rocketdyne (PWR) to develop improved computational tools to predict better combustion stability of hydrocarbon-fueled liquid rocket engines. The Advanced Liquid Rocket Engine Stability Technology -High Fidelity Model (ALREST-HFM) code will be designed to improve the prediction of combustion instability using Computational Fluid Dynamics (CFD). Pratt & Whitney Rocketdyne has assembled a team that includes Professor Suresh Menon ... |
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| High-Order CESE Methods for Solving Hyperbolic PDEs (Preprint) |
03 MAY 2011 |
21 pages |
| Authors:
David L. Bilyeu; Yung-Yu Chen; S. J. Yu; Jean-Luc Cambier; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| In the present paper, we extend Chang's high-order method for system of linear and non-linear hyperbolic partial differential equations. A general formulation is presented for solving the coupled equations with arbitrarily high-order accuracy. To demonstrate the formulation, several linear and non-linear cases are reported. First, we solve a convection equation with source term and the linear acoustics equations. We then solve the Euler equations for acoustic waves, a blast wave, ... |
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| CFD Modeling & Verification in an Aircraft Paint Hangar |
May 2011 |
25 pages |
| Authors:
NAVAL FACILITIES ENGINEERING COMMAND PORT HUENEME CA ENGINEERING SERVICE CENTER
|
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| Development of an Aero-Optics Software Library and Integration into Structured Overset and Unstructured Computational Fluid Dynamics (CFD) Flow Solvers |
APR 2011 |
27 pages |
| Authors:
William J. Coirier; James Stutts; KRATOS DIGITAL FUSION INC HUNTSVILLE AL
|
| An object-oriented software library has been developed that is used to integrate a Paraxial Beam solver within both an overset (OVERFLOW) and an unstructured (AVUS) CFD model.The Paraxial Beam equation is used to propagate optical waveforms through the turbulent, unsteady flow fields produced by the structured overset and unstructured solvers. To achieve this new capability, an object-oriented, software library approach has been undertaken and has been used to develop the ... |
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| Advanced CFD Methods for Hypervelocity Wind Tunnels |
10 Mar 2011 |
24 pages |
| Authors:
Graham V Candler; MINNESOTA UNIV MINNEAPOLIS DEPT OF AEROSPACE ENGINEERING AND MECHANICS
|
| There are two main components of the work performed during this project. First, a finite-rate vibrational energy relaxation model was developed to study how the possible presence of water vapor in the Tunnel 9 facility could affect the flow properties. We find that water vapor levels at about 500 parts per million (ppm) could cause appreciable relaxation of the nitrogen test gas, however, even at these large levels, the effect ... |
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Reports by Keyword(s)
COMPUTATIONAL FLUID DYNAMICS
