| Potential Flow Forces and Moments from Selected Ship Flow Codes in a Set of Numerical Experiments. Appendix B - Time History Plots for Prescribed Heave Motion of Model 5514 |
May-2008 |
675 pages |
| Authors:
NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD
|
 | This appendix contains all the plots and tables for the simulations of task 1 that involve 1-DOF prescribed heave motion of Model 5514 scaled to the length 142 m. Each of Figures B-1 through B-300 contains time-history plots of the results from all codes for a single variable during one period of motion. If the code runner did not supply the data, the data vanish identically, or the data are ... |
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| Potential Flow Forces and Moments from Selected Ship Flow Codes in a Set of Numerical Experiments. Appendix A - Time History Plots for Prescribed Heave Motion of Model 5613 |
May-2008 |
675 pages |
| Authors:
NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD
|
| This appendix contains all the plots and tables for the simulations of task 1 that involve 1-DOF prescribed heave motion of Model 5613 scaled to the length 154 m. Each of Figures A-1 through A-300 contains time-history plots of the results from all codes for a single variable during one period of motion. If the code runner did not supply the data, the data vanish identically, or the data are ... |
|
| Potential Flow Forces and Moments from Selected Ship Flow Codes in a Set of Numerical Experiments. Appendix C - Time History Plots for Prescribed Roll Motion of Model 5613 |
May-2008 |
1280 pages |
| Authors:
NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD
|
| This appendix contains all the plots and tables for the simulations involving 1-DOF prescribed roll motion of Model 5613 scaled to the length 154 m. Each of Figures C-1 through C-570 contains time-history plots of the results from all codes for a single variable during one period of motion. If the code runner did not supply the data, the data vanish identically, or the data are insufficient for a single ... |
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| Trajectory Control for Very Flexible Aircraft |
30 OCT 2006 |
47 pages |
| Authors:
Christopher M. Shearer; Cesnik E. Carlos; MICHIGAN UNIV ANN ARBOR
|
| This paper focuses on trajectory control of the 6-DOF body fixed reference frame located on a very flexible aircraft. The 6-DOF equations of motion of a reference point on the aircraft are coupled with the aeroelastic equations that govern the geometrically nonlinear structural response of the vehicle. A low-order strain-based nonlinear structural analysis coupled with unsteady finitestate potential flow aerodynamics form the basis for the aeroelastic model. The nonlinear beam ... |
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| Bow Wave Measurements of the R/V Athena 1: 2003 |
DEC 2005 |
19 pages |
| Authors:
Thomas C. Fu; Anna Karion; Don C. Walker; James R. Rice; Toby Ratcliffe; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD
|
| The bow wave of the Research Vessel Athena I was quantified using a Quantitative Flow Visualization (QViz) system developed at the Naval Surface Warfare Center, Carderock Division. Although this technique has been used extensively in the towing tank, this experiment represents the first time that such measurements have been obtained in the full scale environment. Measurements were obtained in the protected waters of St. Andrews Bay in proximity to Panama ... |
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| Appendage and Viscous Forces for Ship Motions in Waves |
SEP 2004 |
|
| Authors:
Kevin A. McTaggart; DEFENCE RESEARCH AND DEVELOPMENT ATLANTIC DARTMOUTH (CANADA)
|
 | This report describes the prediction of appendage and viscous forces in Defence Research and Development Canada (DRDC) Atlantic's ShipMo3D library for ship motions in waves. Previously, the ShipMo3D library considered only hull forces due to potential flow. Inclusion of appendage and viscous forces is essential for accurate prediction of ship sway, roll, and yaw motions. Appendage forces are caused by added mass, lift, and viscous effects. Hull viscous forces are ... |
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| Analysis of the Added Mass of a Barge in Restricted Waters, Phase 2 Model |
AUG 2003 |
50 pages |
| Authors:
David R. Kraemer; Michael E. McCormick; JOHNS HOPKINS UNIV BALTIMORE MD DEPT OF CIVIL ENGINEERING
|
| A theoretical analysis of the added mass of barges in restricted waters is presented. The added-mass behaviors with varying waterway and barge parameters are predicted. A numerical technique is used to solve the potential- flow boundary-value problem. The analysis assumes that the Froude number is low. A restriction that the Froude number be less than or equal to 0.1 ensures that the surface waves will be small; this corresponds to ... |
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| Aerodynamics for MDO of an Innovative Configuration |
JUN 2000 |
11 pages |
| Authors:
G. Bernardini; A. Frediani; L. Morino; UNIVERSITA DEGLI STUDI DI TORINO (ITALY) DIPT DI INGEGNERIA AEROSPAZIALE
|
| A numerical methodology for the evaluation of aerodynamic loads acting on a complex lifting configuration is presented. The work is limited to the case of attached high-Reynolds number flows. A viscous/potential interaction technique is utilized to take into account the effects of the viscosity. For the potential-flow analysis, a boundary element formulation is used; for simplicity, only incompressible flows are examined. The theoretical basis of the present methodology is briefly ... |
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| A Multiobjective Approach to Transonic Wing Design by Means of Genetic Algorithms |
JUN 2000 |
12 pages |
| Authors:
A. Vicini; D. Quagliarella; CENTRO ITALIANO RICERCHE AEROSPAZIALI CAPUA
|
| In this work a transonic wing design problem is faced by means of a multiobjective genetic algorithm, and using a full potential flow model. The applications here presented regard both planform and wing section optimization. It is shown how both geometric and aerodynamic constraints can be taken into account, and how the multiobjective approach to optimization can be an effective way to handle conflicting design criteria. An interpolation technique allowing ... |
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| Measurements of the Effects of Tunnel Wall Proximity on the Velocity Field Upstream of a Rod with Vortex Shedding in Low-Speed Flow |
18 APR 2000 |
279 pages |
| Authors:
David R. Hopper; AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH SCHOOL OF ENGINEERING
|
| High cycle fatigue is an important consideration in blade design for turbomachinery. Blades in an engine undergo countless loading cycles in a lifetime, the result of pressure waves that propagate upstream and downstream from disturbances in the flow. Better understanding of these effects would allow blade designers to reduce the effects of high cycle fatigue, such as costly recurring maintenance or catastrophic engine failure. An experimental ... |
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| RANS Analysis of Free-Surface and Bottom Effects on Axisymmetric RCMS |
MAR 2000 |
28 pages |
| Authors:
Henry J. Haussling; Roderick M. Coleman; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD HYDROMECHANICS DIRECTORATE
|
| The UNCLE Reynolds-averaged Navier-Stokes code is used to investigate free-surface and bottom effects on an axisymmetric radio-controlled submarine model. It is shown that the basin bottom and water surface have small but noticeable influences on the hydrodynamic vertical force and pitching moment on the body for typical depths of submergence. The influence of submergence depth and speed on the forces and moments is analyzed. It is ... |
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| Prediction of Propulsor-Induced Maneuvering Forces Using a Coupled Viscous/Potential-Flow Method for Integrated Propulsors |
JUN 1999 |
|
| Authors:
Christopher L. Warren; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF OCEAN ENGINEERING
|
| This thesis develops a method to analyze the maneuvering forces on surfaced and underwater vehicles with complex propulsors. The analysis method is developed for general propellers yet has unique applicability to model highly contracting stern flows associated with integrated propulsors. Integrated propulsors exhibit strong coupling of the various blade rows and duct, if present, to the vehicle stern. The method developed herein provides a robust ... |
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| Flow Field Considerations for Counter Flow Burners |
1999 |
5 pages |
| Authors:
M. P. Davis; J. W. Fleming; B. A. Williams; H. D. Ladouceur; NAVAL RESEARCH LAB WASHINGTON DC CHEMISTRY DIV
|
| Many computational combustion tools (e.g. Sandia OPPDIF code) of opposed jet, counter flow diffusion flames apply a simplified potential flow model for the fluid flow portion of the problem. The resulting solution (for no flame) yields a stagnation region between the two burners and an axial velocity component that is independent of radius. S.C. Rolon recognized the need for experimental evidence to provide justification for ... |
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| Nonlinear Wave Motion |
OCT 1997 |
3 pages |
| Authors:
John W. Miles; H. Cecil; Ida M. Green; CALIFORNIA UNIV SAN DIEGO LA JOLLA INST OF GEOPHYSICS AND PLANETARY PHYSICS
|
| The long term goal of my research is directed toward understanding wave generation and wave motion in the ocean and in laboratory simulations thereof. The prmary approach is through mathematical models. Solutions ultimately are developed in both analytical and numerical form, but the goal is to obtain analytical results that inform phenomenological models for the prediction of physical events. |
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| Evaluation of the CMARC Panel Code Software Suite for the Development of a UAV Aerodynamic Model |
JUN 97 |
151 pages |
| Authors:
Stephen J. Pollard; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| The CMARC panel code is evaluated to verify its accuracy and suitability for the development of an aerodynamic model of the Naval Postgraduate School (NPS) FROG Unmanned Air Vehicle (UAV). CMARC is a DOS personal computer based version of the NASA Panel Method Ames Research Center (PMARC) panel code. The core processing algorithms in CMARC are equivalent to PMARC. CMARC enhancements include improved memory management and command line functionality. Both ... |
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| Parametrics of Near Surface Response of Submersible Vehicles |
SEP 96 |
88 pages |
| Authors:
A. K. Celikel; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Vertical plane response of submersible vehicles in the proximity of a free surface in deep water is evaluated using a potential flow, strip theory solver. Two criteria, that are periscope submergence, and sail broaching are used to quantify the response. These criteria combined with the vehicle's response amplitude operators in regular sinusoidal waves along with a statistical description of the seaway lead to an assessment of an overall operability index ... |
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| Assessment of Shallow Water Near Surface Response of Submersible Vehicles |
JUN 96 |
127 pages |
| Authors:
Ufuk Toprak; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Vertical plane response of submersible vehicles in the proximity of a free surface in both deep and shallow waters is evaluated using a potential flow, strip theory solver. Three criteria, namely periscope submergence, sail broaching, and collision are used to quantify the response. These criteria combined with the vehicle's response amplitude operators in regular sinusoidal waves along with a statistical description of the seaway lead to an assessment of an ... |
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| Experimental Analysis of the Wake of an Oscillating Airfoil |
JUN 96 |
148 pages |
| Authors:
Claus M. Dohring; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| The wake of an airfoil which oscillates in pure plunge mode is investigated in a water tunnel over a wide range of reduced frequency and amplitude. The main focus of this study is the comparison of the experimentally determined wake geometry with numerical results from a potential flow code. The wake vortices are visualized by two-color dye injection and velocity profiles are measured with LDV upstream and downstream of the ... |
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| Proximity Operations of an Underwater Vehicle to a Host Vessel |
MAY 96 |
|
| Authors:
Jess E. Riggle; MASSACHUSETTS INST OF TECH CAMBRIDGE
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| This paper presents a method for estimating the forces and moments on the six axes of an Unmanned Underwater Vehicle (UUV) operating in close proximity to a host vesseL Forces and moments encountered by the vehicle in the host vessel launchway, near the vessel and clear of the launchway, and far away from the host vessel, are modeled from experimental and theoretical sources. A quasi - steady approach to the ... |
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| Evaluation of the Boeing Pan Air Technologies Code (A502i) Through Prediction of Separation Forces on the GBU-24 |
MAR 96 |
116 pages |
| Authors:
Matthew A. LeTourneau; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| The Boeing PAN AIR Technologies code (A502i) is investigated to explore its suitability for determination of separation forces on ordnance. To this end, A502i is first assessed by applying it to three problems for which other solutions and experimental data are available, i.e. steady flow past a rectangular, parabolic arc wing and a delta wing at both subsonic and supersonic conditions. Good agreement is found in all cases. A502i is ... |
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| Numerical Modeling of Wave Breaking Induced by Fixed or Moving Boundaries |
1996 |
39 pages |
| Authors:
Stephan T. Grilli; Ravishankar Subramanya; RHODE ISLAND UNIV NARRAGANSETT DEPT OF OCEAN ENGINEEING
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| In this paper, several numerical aspects of an existing model for fully nonlinear waves are improved and validated to study wave breaking due to shoaling over a gentle plane slope and wave breaking induced by a moving lateral boundary. The model is based on fully nonlinear potential flow theory and combines a higher-order Boundary Element Method (BEM) for solving Laplace's equation at a given time and Lagrangian Taylor expansions for ... |
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| Simulation of a Torpedo Launch Using A 3-D Incompressible Finite Element Solver and Adaptive Remeshing |
30 NOV 95 |
33 pages |
| Authors:
Ravi Ramamurti; Rainald Loehner; William C. Sandberg; NAVAL RESEARCH LAB WASHINGTON DC
|
| An implicit finite element solver for three dimensional incompressible flows with adaptive remeshing has been developed. This flow solver is employed for the simulation of an unsteady torpedo launch from a submarine. Several mesh movement algorithms have been developed and implemented. The use of gliding points on surfaces in the vicinity of a moving body has proven valuable in reducing the number of remeshings and thus reducing the total CPU ... |
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| The Fluid Mechanics of Vortex Cutting by a Blade |
30 SEP 95 |
39 pages |
| Authors:
Jeffrey S. Marshall; IOWA STATE UNIV IOWA CITY
|
| A study of the fluid dynamics associated with impact of a vortex on a body (such as a blade) moving normal to the vortex axis was performed. The physical features of the flow evolution were categorized in terms of two dimensionless parameters which represent a ratio of length scales and a ratio of velocity scales associated with the vortex core and with the body. Models of various features of the ... |
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| Evaluation of the NASA-Ames Panel Method (PMARC) for Aerodynamic Missile Design |
SEP 95 |
84 pages |
| Authors:
Mark A. Lambert; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The NASA Ames Research Center developed panel code (PMARC) is investigated to explore its suitability for aerodynamic missile design. To this end, PMARC is first assessed by applying it to several problems for which other solutions and experimental data are available, i.e., steady flow past a wing- body configuration, delta wings, biplane wings, wings in ground effect, and unsteady flow of pitching and impulsively started wings. Good agreement is found ... |
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| An FVE-FAC Approach for the Weldpool Problem |
SEP 95 |
90 pages |
| Authors:
Thomas E. Rogers; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| A block of metal is subjected to a concentrated heat source resulting in a pool of molten metal surrounded by a portion of the unmelted metal. The governing system of equations is known as the weldpool problem. The weldpool problem is discretized using finite differences to discretize time derivatives and the Finite Volume Element method (FVE) to discretize spatial derivatives. Multigrid methods, known to be effective on uniform grids, make ... |
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| Numerical Investigation of Subsonic Flow Over Bodies of Revolution and a Typical Missile Forebody |
SEP 95 |
128 pages |
| Authors:
Ronald E. Marvin; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| It was the objective of this investigation to study the subsonic flow over a missile forebody. To this end, the NASA Ames developed OVERFLOW, three dimensional, Navier-Stokes Code was applied and detailed results were obtained for the missile forebody. The flow conditions were set at a Mach Number of 0.3 and Reynolds Number of two million for each angle of attack at 0, 2, 6, 10, and 14 degrees. These ... |
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| Predicting the Motions of SWATH Ships in Waves. A Validated Mathematical Model |
JUN 95 |
72 pages |
| Authors:
Kathryn K. McCreight; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD HYDROMECHANICS DIRECT ORATE
|
| A mathematical model for predicting the motions of SWATH ships in waves in the frequency domain is presented. This mathematical model requires definition of only geometric and mass properties. While the mathematical model for the vertical plane presented here differs little from the one which has been used for about a decade, the transverse plane model differs from the previous model in various ways. Predictions are compared to measured model ... |
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| A Wind Tunnel Investigation of a Wing-Tip Trailing Vortex |
25 MAY 95 |
284 pages |
| Authors:
Mark A. Engel; William J. Devenport; VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG DEPT OF AEROSPACE AND OCE AN ENGINEERING
|
| The 3'x2' Subsonic Wind Tunnel was used to study a wing-tip trailing vortex during its development at the wingtip and at 10 chordlengths downstream. The vortex was found to be well developed by 10 chordlengths. Helium bubble flow-visualization was used to study the development of the vortex in the near- tip regions. Hot wire anemometry was used to study the vortex at 10 chordlengths. Two vortices were found in the ... |
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| Seakeeping Aspects Of Slice Hulls |
MAR 95 |
108 pages |
| Authors:
Stephen B. Peffers; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Seakeeping calculations are performed for a new hull design, SLICE. This hull type is a variation of a Small Waterplane Twin Hull (SWATH) ship, with the primary difference of discontinuous fore and aft buoyancy pods. Emphasis in this work is placed on understanding the applicability and limitations of a standard strip theory approach to coupled heave and pitch motions in regular and random seas. It is shown that the coupled ... |
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| Pressure Based High Order TVD Methodology for Dynamic Stall Control |
NOV 94 |
96 pages |
| Authors:
H. Q. Yang; Z. J. Wang; V. J. Harrand; A. J. Przekwas; CFD RESEARCH CORP HUNTSVILLE AL
|
| The objectives were to study various dynamic stall control concepts using a code developed under Phase I. The concepts studied were; vortex flaps, apex fence flaps, forebody strakes, spanwise blowing, leading edge blowing and suction, and forebody blowing and suction. |
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| Computational Fluid Dynamics and Transonic Flow |
31 OCT 94 |
5 pages |
| Authors:
Paul R. Garabedian; NEW YORK UNIV NY COURANT INST OF MATHEMATICAL SCIENCES
|
| The project was concerned with the development of high performance computer codes for problems in transonic aerodynamics. A practical rule to calculate the wave drag for solutions of the Euler equations was developed from an entropy equality. Symmetric shockless airfoils were analyzed for which uniqueness fails in the transonic case not just for potential flow, but also for the Euler equations. |
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| Computational Fluid Dynamics and Transonic Flow |
31 OCT 94 |
6 pages |
| Authors:
Paul R. Garabedian; NEW YORK UNIV NY COURANT INST OF MATHEMATICAL SCIENCES
|
| The project was concerned with the development of high performance computer codes for problems in transonic aerodynamics. A practical rule to calculate the wave drag for solutions of the Euler equations was developed from an entropy equality. Symmetric shockless airfoils were analyzed for which uniqueness fails in the transonic case not just for potential flow, but also for the Euler equations. |
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| Computational Algorithms for Aerodynamic Analysis and Design |
SEP 94 |
13 pages |
| Authors:
Antony Jameson; James Reuther; Luigi Martinelli; PRINCETON UNIV NJ DEPT OF MECHANICAL AND AEROSPACE ENGINEERING
|
| The goal of our research under AFOSR sponsorship is to develop mathematical procedures which can be used to arrive at optimum, or near optimum, aerodynamic shapes by merging techniques from computational fluid dynamics and control theory. With this in mind we have continued to work in two main topics: Development of high resolution shock capturing schemes with low numerical diffusion. Since last year the symmetric limited positive (SLIP) and upstream ... |
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| Evolution of a Collection of Bubbles with Application to Wakes, Bubble Screens, and Cloud Noise |
AUG 94 |
476 pages |
| Authors:
Georges L. Chahine; DYNAFLOW INC FULTON MD
|
| Contents: Bubble Dynamics and Cavitation Inception in Non-Uniform Flow Fields; Bubble Interactions with Vortices; Cavitation Dynamics at Microscale Level; Viscous Interaction Between Bubble and Line Vortex; The Motion of a Spherical Body Below a Free Surface; Study of Jet Instability Formation on Free Surfaces; The Final Stage of the Collapse of a Cavitation Bubble Near a Rigid Walls Study of the Interaction Between a Bubble and a Vortical Structure; Asymptotic ... |
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| A Simulation Program to Project Casualty and Illness Rates |
AUG 94 |
18 pages |
| Authors:
Edward R. O'Donnell; Christopher G. Blood; NAVAL HEALTH RESEARCH CENTER SAN DIEGO CA
|
| A ground casualty projection system (FORECAS) hass been developed to provide medical planners with estimates of expected daily arrivals of disease and non-battle injuries, wounded-in-action, and killed-in-action rates. Statistical characteristics of these rates are used as a basis from which the simulations are developed. By displaying the dispersion, range, and other statistical properties of casualty and illness data, FORECAB graphically depicts the potential patient flows within a theater of operations. ... |
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| Effect of Pressure Gradient on First Mode of Instability in High-Speed Boundary Layers |
APR 94 |
52 pages |
| Authors:
Jamal A. Masad; Yousef H. Zurigat; INSTITUTE FOR COMPUTER APPLICATIONS IN SCIENCE AND ENGINEERING HAMPTON VA
|
| The effect of a pressure gradient on the first mode of instability of compressible subsonic and supersonic boundary layers is investigated using linear stability theory. Formulations are presented for nonsimilar boundary- layer mean flow and linear quasi-parallel stability problems that account for variable fluid properties. A pressure gradient is studied that generates potential-flow Mach number distributions at the edge of the boundary layer of the form M, = cxn, where ... |
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| Course Module for AA201: Wing Structural Design Project |
MAR 94 |
132 pages |
| Authors:
Stephen A. Burris; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| This thesis defined a fundamental approach for aircraft wingbox design appropriate for an introductory course in aircraft structures based upon material strength and stiffness requirements. The process developed sought to encompass major conceptual engineering design considerations that ranged from load estimation at various points in the subsonic flight envelope, to initial structural sizing and layout. The goal was to present a process that could be readily conducted via hand calculations ... |
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| Numerical Solution for the Determination of Towboat Return Currents |
MAR 94 |
38 pages |
| Authors:
Sandra K. Martin; ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS HYDRAULICS LAB
|
| In shallow-draft waterways, commercial towboats and barges generate complex currents as they move through the waterway. The flow, in general, moves from bow to stern as the tow moves forward. The current acting in the direction opposite tow movement and generally parallel to the bank is called the return current. The magnitude of the return current is generally determined using an analytical approach based upon the energy equation along a ... |
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| Relation between the Fluctuating Wall Pressure and the Turbulent Structure of a Boundary Layer on a Cylinder in Axial Flow |
12 AUG 93 |
245 pages |
| Authors:
Stephen R. Snarski; NORTHWESTERN UNIV EVANSTON IL
|
| The turbulent flow structures responsible for the fluctuating wall pressure in the turbulent boundary layer on a cylinder in axial flow (delta/a = 5.04, Re sub Theta = 2870) have been investigated. Simultaneous measurements of the fluctuating wall pressure and turbulent streamwise velocities have been performed throughout a large volume of the boundary layer (y(+) = 14 to y/delta = 1.91, 0 < or = x/delta < or = 1.52, ... |
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| Unsteady Vortex Loop/Dipole Theory Applied to the Work and Acoustics of an Ideal Low Speed Propeller |
MAR 93 |
28 pages |
| Authors:
Earl Quandt; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD PROPULSION AND AUXULI ARY SYSTEMS DEPT
|
| The vortex loop/dipole singularities used to simulate blade lift and thickness in potential flow models of turbomachines are examined in an unsteady form. The three-dimensional potential fields created as these singularities rotate in the absolute frame are shown to provide the input forces, ideal work and wake energy for an incompressible fluid, as well as the tonal acoustics for slight compressibility. For typical low Mach number propellers the sound field ... |
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| Interfacial Tension Studies of Electrified Liquid/Liquid Interfaces: Classical Techniques for New Data |
14 DEC 92 |
11 pages |
| Authors:
Petr Vanysek; NORTHERN ILLINOIS UNIV DE KALB DEPT OF CHEMISTRY
|
| Several general methods used in measurement of interfacial tension are reviewed. Consideration is given to methods that can be used on interfaces with externally applied potential and current flow. A classical technique of interfacial tension measurement, the maximum bubble pressure method, is used to study an interface between two immiscible solutions of electrolytes. This work focuses on data interpretation of systems under interfacial ion transfer. A series of quaternary ammonium ... |
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| Thrust Deduction Prediction For High Speed Combatant Ship |
DEC 92 |
28 pages |
| Authors:
Yoon-Ho Kim; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD SHIP HYDROMECHANICS D EPT
|
| The free surface effects on the hull-propeller interaction characteristic of thrust deduction have been studied for a high speed combatant ship hull form. Through mathematical modelling and a series of numerical computations, we attempt to elucidate the mechanism of this component of hull- propellent interaction from the free surface. SWIFT, a linearized free surface potential flow solver using a higher-order panel method, has been extended to study the interaction between ... |
|
| A Wind Tunnel Study of Magnus Effects on a Differentially Rotating Missile |
DEC 92 |
108 pages |
| Authors:
Karen A. Naselius; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
|
| This study investigates magnus effects on a non-firmed missile model which had three axially rotating sections that span at different rates. Five spin cases are examined; the mid section spinning only; the front and rear sections spinning only; all section spinning at the same speed; all sections spinning in the same direction with the mid section spinning at an additional ten revolutions per second; and all sections spinning with the ... |
|
| Pressure and Temperature for B-1B Transparency Test |
MAY 92 |
122 pages |
| Authors:
Elijah W. Turner; John T. Riechers; WRIGHT LAB WRIGHT-PATTERSON AFB OH
|
| Pressure and temperature data are presented for life cycle testing of the B-lB transparency. For each of three mission types, contour plots of pressure and temperature are presented for each mission segment. Potential flow theory was used to calculate pressure. Isentropic flow was assumed for calculating temperature. |
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| Recent Applications of Linear and Nonlinear Unsteady Aerodynamics for Aeroelastic Analysis, |
MAR 1992 |
|
| Authors:
Bengt Winzell; SAAB AIRCRAFT CO LINKOEPING (SWEDEN)
|
| Results of unsteady linear and full potential theory are used for analysis of wings and aircraft configurations. In particular the details of unsteady pressure distributions at the trailing edge are investigated aiming at better representation of control surface hinge moments. The importance of viscous effects are observed and a comparison between potential theory and Navier-Stokes predictions is made. |
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| A Boundary Integral Formulation for Unsteady Transonic Potential Flows, |
MAR 1992 |
|
| Authors:
U. Iemma; F. Mastroddi; L. Morino; M. Pecora; ROME UNIV (ITALY)
|
| A boundary integral formulation for the analysis of unsteady potential transonic flows around airplanes is presented. The formulation is applied to steady and unsteady two-dimensional and three-dimensional configurations under the small-perturbation assumption. The results are compared with existing numerical and/or experimental results, and demonstrate that the algorithm is capable of capturing shocks. However, the location predicted appears to be ahead of that predicted by conservative finite-difference schemes; nonetheless, considering the ... |
|
| A Compilation of the Mathematics Leading to the Doublet Lattice Method |
MAR 92 |
145 pages |
| Authors:
Max Blair; WRIGHT LAB WRIGHT-PATTERSON AFB OH
|
| This report provides a theoretical development of the doublet lattice method, the method of choice for most subsonic unsteady aerodynamic modelling for over twenty years. This is a tutorial based on many-key mathematical developments provided in the References section. An example source code is provided in the Appendix. UNSTEADY AERODYNAMICS, DOUBLET LATTICE, POTENTIAL FLOW, SUBSONIC AERODYNAMICS, AEROELASTICITY. |
|
| Extension of the Integral Equation Formulation of Linearized Time Dependent Subsonic Flow |
FEB 92 |
|
| Authors:
Marc H. Williams; PURDUE UNIV LAFAYETTE IN SCHOOL OF AERONAUTICS AND ASTRONAUTICS
|
| This report describes the results of a study of the feasibility of extending the time domain formulation of the linearized aerodynamics of flexible bodies that had been developed earlier for planar wings to the general case of arbitrary, complete aircraft, configurations. The end products of that study are a formulation of the problem, an exact solution applicable to any geometry, a sample calculation for a simple nonplanar configuration, and some ... |
|
| Computation of Planar Store Trajectories Using an Adaptive Grid Procedure |
DEC 91 |
102 pages |
| Authors:
William D. Hack; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
|
| The objective of this research was to compare a quasi-analytical, potential flow/three-degree-of-freedom model to an implicit-Euler algorithm for the calculation of store trajectories. The implicity algorithm uses a cell- centered, finite-volume, spatial discretization applied to the Euler equations, written in time-dependent, curvilinear-coordinates. A flux-differencing Roe scheme is employed to find the split-fluxes and the Steger/Warming flux-vector method is used to calculate the flux-Jacobians. The potential flow and implicit- Euler algorithm ... |
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| The Effect of Defense Management Review Decision 904, Stock Funding Depot Level Reparables, on Cash Flow within the Reparable Support Division of the Air Force Stock Fund |
AUG 91 |
|
| Authors:
Deborah A. Elliot; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
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| This study investigated what the potential cash flow condition of the Reparable Support Division of the Air Force Stock Fund might be after final implementation of the procedures outlined in Defense Management Review Decision 904, Stock Funding Depot Level Reparables. The operation of the future Reparable Support Division was modelled using the General Purpose Simulation Software (GPSS/H) package and future cash flow conditions were projected through use of this model. ... |
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Reports by Keyword(s)
POTENTIAL FLOW
