| Innovative Fusion of Experiment and Analysis for Missile Design and Flight Simulation |
01-May-2006 |
41 pages |
| Authors:
Daniel J Lesieutre; Marnix F Dillenius; Patrick H Reisenthel; John F Love; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
 | The integration of experimental data and computational databases is key to supporting decisions during the development of missile systems. An innovative technique is demonstrated to increase the accuracy of databases used for comprehensive flight simulations of missiles. This technique uses multidimensional response surface technology to mutually enhance heterogeneous data sets. An important application of this technology is the use of sparse data points from limited wind tunnel tests to correct/calibrate ... |
|
| Store Separation Simulation of the Penguin Missile from Helicopters |
May-2006 |
44 pages |
| Authors:
Daniel J Lesieutre; Marnix F Dillenius; Jens A Gjestvang; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| Under contract to Kongsberg Defence & Aerospace (KDA), Nielsen Engineering & Research (NEAR) combined and extended store separation simulation code NEAR STRLNCH and aerodynamic prediction code NEAR MISDL to simulate and analyze launch and separation of the KDA Penguin missile from a helicopter. One of the objectives was to enable the running of many cases in relatively short time on readily available computer platforms. The resulting MISDL/KDA code was validated ... |
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| Advanced Adaptive CFD Methodology for Dynamic Stall |
03 JUL 1997 |
7 pages |
| Authors:
Patrick H. Reisenthel; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| This is the first of four quarterly technical reports submitted under ARO contract number DAAG55-97-C-0029. This Phase 2 SBIR concerns the development of an advanced adaptive CFD capability for predicting the phenomenon of dynamic stall. The new CFD capability is based on the concept of Unstructured MacroCells (UMC). The present report is a description of the work accomplished during the period of April 1, 1997, to July 2, 1997. ... |
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| A Study of Compressible Turbulence |
29 MAY 96 |
32 pages |
| Authors:
Robert E. Childs; Patrick H. Reisenthel; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| Numerical simulations have been used to study the effects of compressibility on turbulence. Statistical and structural changes in turbulence are observed in both mixing layers and boundary layers due to dynamical compressibility effects. In mixing layers, the coherent large-scale vortices which dominate turbulent momentum transport change from being roughly spanwise at low convective Mach numbers to being oblique at elevated convective Mach numbers, roughly Mc > 0.7. Simulations of boundary ... |
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| Vorticity Dynamics and Control of Dynamic Stall |
18 AUG 94 |
129 pages |
| Authors:
Patrick H. Reisenthel; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| The goal of the research was to understand key issues of vorticity dynamics prior to, during, and after the initiation of dynamic stall. The first portion of this work examined the of indicial theory to the predIction of dynamic applicability stall. The research focused on extending the semi- analytical formalism of indicial theory to predict the vorticity fluxes and the vorticity accumulation at the leading edge during unsteady maneuver. In ... |
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| Hypertext Knowledge Presentation System to Transition Basic Research |
22 JUN 94 |
42 pages |
| Authors:
Laura C. Rodman; David Nixon; Stanley C. Perkins Jr.; Teresa O. Lesieutre; Michael R. Mendenhall; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| Efficient technology transfer from the basic research community to the engineering development community is essential for maintaining technological competitiveness. However, the research and the design communities have different objectives, and they also have different perspectives on relevant technical knowledge. In this work, the communication issues resulting from the differing perspectives of these two communities are addressed with a hypertext knowledge presentation system for technology transfer. The objective of this work ... |
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| Controlling Combustion and Maximizing Heat Release in a Reacting Compressible Free Shear Layer |
11 FEB 94 |
38 pages |
| Authors:
David Nixon; Laurence R. Keefe; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| The objective of this work has been to study the interaction between heat release and mixing in compressible shear layers by analysis and computation, with an eye to finding flow configurations that maximize the heat release per unit distance in the stream direction. The principal prediction is that heat release asymmetry across the layer can enhance mixing over the non- heat release case, but the effect appears too small to ... |
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| Methods for Reducing Turbulent Flow Aero-Optical Distortion |
31 MAR 93 |
|
| Authors:
Robert E. Childs; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
 | Methods for reducing the aero-optical distortion which affects jet- cooled seeker windows on high-speed, endo-atmospheric interceptors were studied. Reductions in turbulence were achieved by curving the shear layer in the streamwise direction. This type of curvature corresponds to a window whose outer surface is convex in the axial direction. For a case with moderate curvature, the peak shear stress and density fluctuations were reduced by 85% compared to an otherwise ... |
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| Turbulence Modeling for Thrust Reverser Flow Field Prediction Methods |
DEC 92 |
70 pages |
| Authors:
Robert E. Childs; Laura C. Rodman; Peter Bradshaw; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| The use of thrust reversing on aircraft operating in ground effect produces complex flow fields, for which conventional turbulence models are inadequate. The main objective of the work was to produce an improved turbulence model. The work included experimental measurements of an impinging jet inclined 45 degrees into the crossflow. Large eddy simulation (LES) was used to identify the dominant turbulent physics in these flows and to guide the development ... |
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| A Study of Compressible Turbulence |
31 JAN 92 |
|
| Authors:
D. Nixon; R. E. Childs; L. R. Keefe; L. C. Rodman; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| This work involves theoretical analyses of turbulence in high speed flow and large eddy simulation results for the mixing layer. Analysis indicates that turbulence is dominated by streamwise vortices as the Mach number approaches infinity. A conceptual model based on swept vortices makes predictions about the sweep angle of these vortices from spanwise at low speeds to streamwise at high speeds, and about the reduced spreading rate at high speeds. ... |
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| Supersonic Submunition Aerodynamics During Dispense. |
MAY 1991 |
|
| Authors:
S. C. Perkins; M. F. Dillenius; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
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| Computational Analysis of High-Speed Ejection Seats |
20 APR 91 |
86 pages |
| Authors:
Steven C. Caruso; Michael R. Mendenhall; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| This final report documents the results of a study demonstrating the use of analytical computational fluid dynamics methods to predict the aerodynamic characteristics and flowfield details of a typical ejection seat with an occupant. This feasibility study was limited to two dimensional flow around a configuration defined by a longitudinal plane of symmetry through the center of the ejection seat. Navier-Stokes codes were used to predict the steady and time-dependent ... |
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| Advanced Methods for Atmospheric Modeling |
31 JAN 91 |
|
| Authors:
Laura C. Rodman; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| The evolution of physical processes in a numerical simulation of the atmosphere and the effects of their interactions on a forecast are very complex and difficult to isolate. An analysis was developed which uses artificial intelligence techniques to study the time-evolving quantities in a numerical simulation in order to determine the relationships among various flow parameters. This procedure was divided into two parts. First, the data was manipulated into a ... |
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| The Effects of Compressibility on a Supersonic Mixing Layer |
30 JAN 91 |
|
| Authors:
D. Nixon; L. R. Keefe; G. D. Kuhn; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| The objective of the work is to identify the flow mechanisms that cause the decrease in spreading rate of supersonic mixing layers as the convective Mach number increases and to suggest means of enhancing the mixing. Two approaches have been taken, one numerical and one analytic. A computer code, TMRC, has been used to simulate both time and space developing two-dimensional mixing layers to get some indication of the flow ... |
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| Prediction of Unsteady Transonic Separated Flow for Missile Applications |
20 NOV 90 |
|
| Authors:
P. Reisenthel; D. Nixon; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| A theory was developed to treat flow separation and related vortex effects in unsteady transonic flow around slender bodies. This theory involves the simultaneous solution of a modified Transonic Small Disturbance Equation, a kinematic vector potential equation, and a three-dimensional transport equation for the streamwise vorticity. In this theory, flow separation is modeled using normal vorticity jets placed along the separation line. The location and strength of the separating vorticity ... |
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| A Study of Supermanuever Aerodynamics |
31 JAN 90 |
|
| Authors:
David Nixon; Laura C. Rodman; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| The objective of this work is to develop a novel technique for studying transient separated flows, such as those typical for maneuvering aircraft. The ultimate goal of this research is to develop flow control techniques using the boundary conditions in a Navier Stokes calculation. Once numerical boundary conditions are established, then their physical counterparts may be found. A subdomain technique was developed which allows the study of the effects of ... |
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| The Effects of Compressibility on a Supersonic Mixing Layer |
28 DEC 89 |
|
| Authors:
D. Nixon; L. R. Keefe; G. D. Kuhn; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| The objective of the work is to identify the flow mechanism that cause the decrease in spreading rate of supersonic mixing layers as the convective Mach number increases and to suggest means of enhancing the mixing. Two approaches have been taken, one numerical and one analytic. A computer code, TMRC, has been used to simulate both time and space developing mixing layers to get some indication of the flow physics. ... |
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| Numerical Simulation of a Turbulent Flow through a Shock Wave |
21 APR 89 |
|
| Authors:
David Nixon; Gary D. Kuhn; Mohammad Farshchi; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| This report describes the results of research into the interactions between shock waves and turbulent flows using numerical simulations. The research was conducted at transonic speeds with a normal shock wave and two dimensional turbulence, making use of existing knowledge and computational methods for developing insight to the shock/turbulence interaction. The results indicate that the shock has a significant effect on the turbulence. The shock produces a jump in the ... |
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| Vortex Induced Characteristics of Missiles in Unsteady Maneuvers, |
MAR 1989 |
|
| Authors:
Michael R. Mendenhall; Stanley C. Perkins Jr; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| A preliminary design method to predict the nonlinear aerodynamic characteristics of tactical missiles in unsteady maneuvers at high angles of attack in subsonic flow is described. The approach is based on the accurate representation of the complex flow phenomena in the vicinity of the missile, including effects of forebody vortex shedding and lifting surface trailing vorticity. For specified motion of the missile, the time-dependent forces and moments on all missile ... |
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| Aeroelastic Tailoring Procedure for Controlling Fin Hinge Moments, |
MAR 1989 |
|
| Authors:
M. F. Dillenius; S. C. McIntosh Jr; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| A combined static aeroelastic and optimization design method is presented which is aimed at controlling the center of pressure acting on a missile control fin made of composite material. Specifically, the material principal-axis directions of various segments of an orthotropic fin are varied in order to influence the chordwise location of the center of pressure through elastic fin deformation under nonlinear supersonic aerodynamic loading. The design problem is posed as ... |
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| Exploitation of Multiple Solutions of the Navier-Stokes Equations to Achieve Radically Improved Flight |
27 FEB 89 |
|
| Authors:
David Nixon; S. C. Caruso; M. Farshchi; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| It is known that the nonlinear Navier Stokes equations will model most fluid flow of aeronautical interest. The existence and uniqueness of the solutions to the Navier-Stokes equations have not been proven although it is known that in certain cases only the most stable solution is obtained. This present work is concerned with identifying multiple solutions of the Navier- Stokes equations for transonic flow. The objective is to exploit the ... |
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| Computational Study of High Supersonic Flow Over Boattails with Centered Propulsive Jets |
31 JAN 89 |
|
| Authors:
Robert E. Childs; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| The present study concerns the ability to achieve good accuracy in missile after body flow predictions based on the Reynolds-averaged Navier-Stokes equations. The problems of numerical accuracy and turbulence modeling are addressed. By employing grids which were cell clustered and which have grid lines aligned with streamlines in shear layers, it was possible to obtain numerically accurate solutions and to obtain solutions at very high nozzle pressure ratios. The effects ... |
|
| Proceedings: Missile Aerodynamics. NEAR (Neilsen Engineering and Research, Incorporated) Conference on Missile Aerodynamics Held in Monterey, California on October 31-November 2, 1988 |
89 |
|
| Authors:
Michael R. Mendenhall; David Nixon; Marnix F. Dillenius; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| Contents: A Survey of Missile Aerodynamics; Missile Dynamics: A critical Assessment of Prediction Capabilities; Appropriate Aeroprediction Accuracy in Defining Missile Systems for Aerodynamic Flight; Application of Experimental Techniques to Store Release Problems; Use of Semiempirical Aerodynamic Methods for Preliminary Design; The Role of Computational Fluid Dynamics in Missile Aerodynamics; A Review of High-Speed, Convective, Heat- Transfer Computation Methods; Prediction Methods For Store Separation; High Performance Missiles of the Future; The ... |
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| Spray Formation: Three-Dimensional Liquid Break-Up due to Surface Tension |
09 AUG 88 |
|
| Authors:
Robert E. Childs; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| The growth instabilities on the interface between a liquid jet and its gaseous environment is an important mechanism in spray atomization, and it is the subject of the work reported herein. Numerical simulations based on the Navier-Stokes equations were used to model liquid/gas interface flows. An algorithm was developed for solving the unsteady Navier-Stokes equations for incompressible fluid with a discontinuity in density and with surface tensions and its accuracy ... |
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| Nonlinear Error Analysis of Finite Difference Solutions of Turbulent and Unsteady Flow Fields |
23 MAY 88 |
|
| Authors:
D. S. McRae; Goetz H. Klopfer; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| A computational analysis is performed for the truncation errors incurred in the numerical time integration of the unsteady and/or turbulent Navier-Stokes equations. The means of analysis is via the modified equation approach. Both the MacCormack explicit and Beam-Warming implicit numerical methods are considered. A simplified analysis applied to Burger's equation indicates that the leading order term is both dissipative and dispersive. The modified equation is derived for the aforementioned explicit ... |
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| Survey on Nonlinear Effects, |
APR 1988 |
|
| Authors:
Marnix F. Dillenius; Stanley C. Perkins Jr; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| This lecture describes a survey of experimental observations and intermediate level prediction methods aimed at nonlinear aerodynamic characteristics of tactical missiles. A description is given of the major differences between missile and aircraft flight and configuration characteristics. The importance of vortical interference and nonlinear compressibility due to shocks is stressed. Nonlinearities associated with deformable fin design, supersonic fin on body interference, wraparound fins, and unsteady flight are discussed. Summarized accounts ... |
|
| Missile Aerodynamics |
88 |
|
| Authors:
NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| One purpose of this chapter is to point out some of the differences between airplanes and missiles by virtue of which missile aerodynamics embraces subjects not formerly of great interest in airplane aerodynamics. Another purpose is to collect in one place for ready reference many of the symbols, definitions, and conventions used throughout the book. Contents: Some Formulas Commonly Used in Missile Aerodynamics; Slender-Body Theory at Supersonic and Subsonic Speeds; ... |
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| On the Accuracy of Turbulent Base Flow Predictions |
10 JUN 87 |
|
| Authors:
Robert E. Childs; Steven C. Caruso; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| Flow in the afterbody region of a supersonic vehicle with propulsive jets iss difficult to predict accurately partly because the complex pattern of shocks, expansion fans, and free shear layers is difficult to resolve, and partly because the turbulence is difficult to model. This report addresses problems of numerical resolution and turbulence modeling and shows that, while insufficient resolution causes some errors, larger errors can be attributed to the turbulence ... |
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| Spray Formation: 3D Liquid Breakup Due to Surface Tension |
11 MAY 87 |
|
| Authors:
Robert E. Childs; Nagi N. Mansour; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| The objective of the work was the investigation of fluid dynamic and surface tension instabilities that effect the breakup of fuel jets in the atomization process. Computational and analytical methods were used. Initial work involved the evaluation of numerical methods for flows with density discontinuities. It was discovered that many commonly used methods are poorly suited to predicting two phase flows. However, a suitable method was found, and it was ... |
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| An Investigation of Wing Lift Augmentation with Spanwise Tip Blowing |
22 APR 87 |
|
| Authors:
Michael R. Mendenhall; Steven C. Caruso; Daniel J. Lesieutre; Robert E. Childs; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| Experimental and analytical investigations or lift augmentation on fighter type wings with wing tip blowing are described. Results of a small-scale wind tunnel test program in the NEAR, Inc. facility are presented for three wings with a wide range of tip nozzle configurations. Effects of nozzle geometry and blowing rate are described, and optimum tip nozzles are selected for further examination in a large-scale test. Results from a large scale ... |
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| A Study of Supermaneuver Aerodynamics |
13 FEB 87 |
|
| Authors:
David Nixon; Mohammad Farshchi; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| An innovative method of examining fluid flow phenomena is described and preliminary results are given. The technique uses a subproblem formulation which examines only those portions of the flow which are of interest. The particular flow examined is that of a stalled airfoil and the objective of the technique is to to develop ways of controlling the stall. Both conventional and nonconventional means of stall control have been examined and ... |
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| Prediction of Vortex Shedding from Circular and Noncircular Bodies in Subsonic Flow |
JAN 87 |
168 pages |
| Authors:
Michael R. Mendenhall; Daniel J. Lesieutre; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| An engineering prediction method and associated computer code VTXCLD are presented which predict nose vortex shedding from circular and noncircular bodies in subsonic flow at angles of attack and roll. The axisymmetric body is represented by point sources and doublets, and noncircular cross sections are transformed to a circle by either analytical or numerical conformal transformations. The leeward vortices are modeled by discrete vortices in cross- flow planes along the ... |
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| Prediction of the Aerodynamic Characteristics of Cruciform Missiles Including Effects of Roll Angle and Control Deflection |
01 AUG 86 |
|
| Authors:
Daniel J. Lesieutre; Michael R. Mendenhall; Susana M. Nazario; Michael J. Hemsch; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| A missile-fin data base for a wide range of configurations and flow conditions was obtained. These data were incorporated into an engineering method for predicting the aerodynamic characteristics of typical cruciform configurations over a wide range of angles of attack, fin deflection angles, roll angles, and Mach numbers. This report documents the test programs, describes the new code, MISSILE 3, and presents comparisons of independent experiment and predicted results to ... |
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| Fundamental Study of Jet Flows |
30 JUN 86 |
|
| Authors:
David Nixon; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| The physics of some problems that arise in impinging jet flows have been investigated using a Very Large Eddy Simulation (VLES) of the Navier Stokes equations. The problems that have been examined include the upwash fountain covered by the collision of two walljets, possible causes of a Reynolds number scaling in the suck down phenomena and possible flow resonance. The effects of heat were also studied. It was found that ... |
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| A Report on a Workshop on Turbulence Research Held in Mountain View, California, August 1985 |
28 MAR 86 |
|
| Authors:
David Nixon; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| The state of the art of turbulence research can be summarized as follows: (1) Experimental studies of turbulence deal with reasonably realistic Reynolds numbers but with a relative scarcity of data, in particular, pressure fluctuation data. (2) Direct Numerical Simulations of turbulence are limited in the range of Reynolds numbers that can be modeled, while the accuracy of the LES sub-grid-scale models and the numerical techniques used in the simulations ... |
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| Prediction of Gust Loadings and Alleviation at Transonic Speeds |
MAR 86 |
|
| Authors:
David Nixon; Keh L. Tzuoo; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| The transonic indicial theory is used to predict the effect of a gust on an airfoil at transonic speeds. The effect of operating two control surfaces is also modeled by the indicial method. The transonic indicial mehtod is linear in a strained coordinate system and superposition can be used. This allows the effects of an arbitrary gust and control surface deflection to be modeled simply if the indicial responses for ... |
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| High Mach Number Predictive Methods for Missile Configurations |
JUL 85 |
|
| Authors:
G. H. Klopfer; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| This report provides an overview of the numerical research conducted on steady supersonic inviscid flows with crossflow separation during the period of May 1982 through May 1985. The publications resulting from that research are summarized. |
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| Extension of Equivalent Angle-of-Attack Method for Nonlinear Flowfields. |
JUN 1985 |
|
| Authors:
M. J. Hemsch; J. N. Nielsen; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| Recent experimental results show that the control effectiveness of a missile fin in supersonic flow at moderate to high angles of attack is a strong nonlinear function of freestream Mach number, body incidence angle, fin bank angle, and fin deflection angle. Analysis of the experimental results using an Euler finite-difference computer code with flow separation, together with the equivalent angle-of-attack concept, indicates that the observed nonlinearities are due to the ... |
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| Notes on Unsteady Transonic Cascade Flows |
08 MAY 85 |
|
| Authors:
D. Nixon; K. Tzuoo; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| Several topics concerned with the unsteady transonic flow through cascades are considered. The indicial theory developed in previous work for cascade flows is examined and certain shortcomings eliminated. A consequence of this work is that some questions regarding the appropriate far field boundary conditions to use are raised. The 'strong shock' potential theory previously developed for isolated airfoil flows has been incorporated into the cascade code. A major topic in ... |
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| A Fundamental Study of Jet Flows |
APR 85 |
|
| Authors:
David Nixon; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| This work investigated the fluid mechanics of impinging jet flows and to this end a combined theoretical, computational and experimental study was initiated. A very detailed set of experimental results for multiple impinging jets in a crossflow is available. The theoretical and computational study is concerned partly with modeling of the turbulence. An important result is that it appears that even the most sophisticated turbulence model available will not reproduce ... |
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| Preliminary Development of an Approximation Procedure for Supercritical Wing Design Optimization Applications |
28 DEC 84 |
|
| Authors:
S. S. Stahara; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| An investigation was carried out involving the preliminary development of an approximation procedure and associated computational codes for rapidly determining approximations to nonlinear, three-dimensional flow solutions, with the purpose of establishing a method for minimizing the computational work requirements associated with design optimization studies of supercritical wings. The results here concern the extension of a previously- developed successful approximation method for determining accurate approximations to two-dimensional nonlinear transonic flows involving ... |
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| Computational Models of the Viscous Sublayer and Limiting Behavior of Turbulence Near a Wall |
DEC 84 |
|
| Authors:
D. R. Chapman; G. D. Kuhn; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| Three computational models of incompressible viscous sublayer turbulence have been developed using the time-dependent Navier-Stokes equations with prescribed velocity boundary conditions at the outer edge of the sublayer. The models attempt in different ways to simulate the highly elongate, quasi- periodic, coherent structures observed experimentally. Comparison of computed results with experiment is good for mean streamwise velocity, mean Reynolds stress, and correlation coefficient; and reasonably good for the three turbulence ... |
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| Studies of Structure and Modeling in Turbulent Shear Flows |
DEC 84 |
|
| Authors:
J. H. Ferzinger; O. J. McMillan; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| Several issues connected with turbulence and its modeling were studied using the results of full simulations of homogeneous turbulent flows. It was found that the mechanism of turbulence production in homogeneous sheared turbulence resembles the mechanism of the turbulence production in the mixing layer. It appears that it is possible to fit a wide range of shear flows, which have greatly different physical behavior, with a single turbulence model. A ... |
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| Research into Topics in Transonic Flow Theory |
NOV 1984 |
|
| Authors:
D. Nixon; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| The contract concerned certain research topics in transonic flow, mainly addressing the questions of why corrections for entropy and viscosity to transonic potential theory were large in certain cases. The physical implications arising from the accurate use of each of these corrections are incompatible. The investigations is due to the fact that the potential equation admits non-unique solution branches and that the corrections, in addition to modeling entropy and viscosity, ... |
|
| Large Eddy Simulation of Turbulent Flow in Channels with Wavy Walls Including Both Compliant Walls and Walls with Prescribed Motion |
JUL 1984 |
|
| Authors:
G. D. Kuhn; J. H. Ferziger; P. Moin; J. Kim; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| The effects of prescribed wall motion on turbulent channel flow were examined with the objective of understanding the drag mechanisms and obtaining a possible means for drag reduction. A computer program for large-eddy simulation (LES) of turbulent flow in a channel was modified to treat the case of time- varying wall motion using linearized boundary conditions. The code was applied to flow in a channel with prescribed wall motion on ... |
|
| Research on Topics in Perturbation Methods, Transonic Flow Theory, Numerical Analysis and Adaptive Grid Generation |
APR 1984 |
|
| Authors:
D. Nixon; G. H. Klopfer; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| This report summarizes work performed during the period April 1, 1979 to January 31. The work is concerned with certain topics on perturbation theory, transonic flow theory, numerical analysis, and adaptive grid generation. |
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| Prediction of Cruciform All-Movable Control Characteristics at Transonic Speeds |
MAR 1984 |
|
| Authors:
J. N. Nielsen; F. K. Goodwin; M. F. E. Dillenius; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| A study has been made of the feasibility of developing a transonic hinge-moment prediction method for cruciform all-movable controls by correlating an extensive data base using the equivalent angle of attack concept. Body vortex effects have been handled using a simplified vortex model. Existing data from the Army generalized missile have been studied to examine transonic nonlinearities including pitch-yaw coupling and fin-fin control interference. Data for an aspect ratio 3.53, ... |
|
| Studies and Vorticity Effects by the Euler Equations with Emphasis on Supersonic Flow Fields |
OCT 1983 |
|
| Authors:
J. N. Nielsen; G. D. Kuhn; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| The primary purpose of the present report is to demonstrate how well the Euler equations in a supersonic marching program (SWINT) can predict the flow fields of bodies, wings, and wing-body combinations. The motivation was to see if if the Euler equations will predict the fin loads in highly vortical flow fields for cruciform missiles. Body-alone and wing-body flow fields were measured in the Bumblebee Program at a position where ... |
|
| Triservice Program for Extending Missile Aerodynamic Data Base and Prediction Program Using Rational Modeling |
AUG 1983 |
|
| Authors:
Michael J. Hemsch; Jack N. Nielsen; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
| The work described in this report was accomplished during the third year of the Triservice program for extending the missile aerodynamic data base and incorporating the new data into the predictive program known as MISSILE. The work consisted of four aspects: support of the ongoing wind tunnel tests, preparation for processing the data to be incorporated into the data base, methods development, and code development. (Author) |
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| Equivalent Angle-of-Attack Method for Estimating Nonlinear Aerodynamics of Missile Fins. |
AUG 1983 |
|
| Authors:
M. J. Hemsch; J. N. Nielsen; NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
|
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Reports by Corporate Author
