New ultrasonic modeling findings are presented contributing to ten fundamental problems related to low-frequency seismoacoustic wave phenomena resulting from the interaction of underwater acoustic waves with heterogeneous elastic boundaries such as the ice cover and/or ocean bottom. The results are described in ten independent sections covering the following problems: (1) backscattering of Scholte waves and grazing underwater acoustic waves by a trench at a liquid/solid interface, (2)...

Topics: DTIC Archive, Chamuel, Jacques R, SONOQUEST ADVANCED ULTRASONICS RESEARCH WELLESLEY HILLS MA,...

Results from experimental and analytical efforts performed on the Passive Nosetip Technology (PANT) program between May 1973 and December 1974 are reported. Four test programs were conducted consisting of one test series in the AFFDL 50 MW arc heater, and three test series in the Naval Ordnance Laboratory, Wind Tunnel No. 8. Test objectives and nominal results are summarized for each test series. Analysis of heat transfer and boundary layer transition data are described and changes to nosetip...

Topics: DTIC Archive, Wool, M. R., SPACE AND MISSILE SYSTEMS ORGANIZATION LOS ANGELES CA, *REENTRY...

The paper is devoted to an experimental study of the laminar-turbulent transition in a self-similar boundary layer with an adverse pressure gradient (APG). The main attention is paid to dominating mechanisms of weakly-nonlinear interactions between the wide-band frequency-wavenumber spectrum of Tollmien-Schlichting (TS) waves (i.e. the noise-like instability waves) and a 2D primary TS-wave. In previous experiments devoted to weakly-nonlinear stages of the APG boundary-layers transition only...

Topics: DTIC Archive, Borodulin, V I, RUSSIAN ACADEMY OF SCIENCES NOVOSIBIRSK INST OF THEORETICAL AND...

Three-dimensional unstable boundary layers were investigated as to their characteristic instabilities, leading to turbulence. Standing cross-flow instabilities and traveling waves preceding the transition were visualized with the hydrogen bubble technique in the boundary layer above the wall of a swept cylinder. With the sublimation method and hot film technique, a model consisting of a swept flat plate with a pressure-inducing displacement body in the 1 m wind tunnel was studied. Standing...

Topics: NASA Technical Reports Server (NTRS), BOUNDARY LAYER STABILITY, BOUNDARY LAYER TRANSITION, CROSS...

The HIFiRE Flight 5 payload was assessed in the NASA LaRC 20-Inch Mach 6 Air Tunnel. The primary objectives were to determine the boundary layer transition characteristics and the effectiveness trips. Boundary layer profiles were extracted from Navier-Stokes calculations of the flow field, and were used to assess trip heights in terms of typical trip correlating parameters. Leading-edge roughness was well-correlated with the R-bar-star parameter. This correlation was used to extrapolate wind...

Topics: DTIC Archive, AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AIR VEHICLES DIRECTORATE, *BOUNDARY...

For aerodynamic and hydrodynamic vehicles, it is highly desirable to reduce drag and noise levels. A reduction in drag leads to fuel savings. In particular for submersible vehicles, a decrease in noise levels inhibits detection. A suggested means to obtain these reduction goals is by delaying the transition from laminar to turbulent flow in external boundary layers. For hydrodynamic applications, a passive device which shows promise for transition delays is the compliant coating. In previous...

Topics: NASA Technical Reports Server (NTRS), BOUNDARY LAYER TRANSITION, STABILITY, MATHEMATICAL MODELS,...

The boundary layer receptivity to free-stream acoustic waves in the presence of localized surface disturbances is studied for the case of incompressible Falkner-Skan flows with adverse pressure gradients. These boundary layers are unstable to both viscous and inviscid (i.e., inflectional) modes, and the finite Reynolds number extension of the Goldstein-Ruban theory provides a convenient method to compare the efficiency of the localized receptivity processes in these two cases. The value of the...

Topics: NASA Technical Reports Server (NTRS), BOUNDARY LAYER TRANSITION, FALKNER-SKAN EQUATION, LAMINAR...

The implementation of a two-equation k-omega turbulence model into the NPARC flow solver is described. Motivation for the selection of this model is given, major code modifications are outlined, new imputs to the code are described, and results are presented for several validation cases: an incompressible flow over a smooth flat plate, a subsonic diffuser flow, and a shock-induced separated flow. Comparison of results with the k-epsilon model indicate that the k-omega model predicts simple...

Topics: NASA Technical Reports Server (NTRS), APPLICATIONS PROGRAMS (COMPUTERS), BOUNDARY LAYER FLOW,...

A design method has been developed by which an airfoil with a substantial amount of natural laminar flow can be designed, while maintaining other aerodynamic and geometric constraints. After obtaining the initial airfoil's pressure distribution at the design lift coefficient using an Euler solver coupled with an integral turbulent boundary layer method, the calculations from a laminar boundary layer solver are used by a stability analysis code to obtain estimates of the transition location...

Topics: NASA Technical Reports Server (NTRS), LAMINAR FLOW, AIRFOILS, LAMINAR BOUNDARY LAYER, PRESSURE...

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Jul 11, 2010
07/10

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NON

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Topics: BOUNDARY LAYER TRANSITION, VISCOUS FLUIDS, DRAG MEASUREMENT, HYDRODYNAMICS, TURBULENT FLOW,...

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Jul 11, 2010
07/10

by
Goertler, H

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No Abstract Available

Topics: BOUNDARY LAYER TRANSITION, COOLING, CYLINDRICAL BODIES, SURFACE ROUGHNESS EFFECTS, CIRCULAR CONES,...

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Jul 23, 2010
07/10

by
Warmbrod, John D

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The objective was to verify the design thermal environments for the Space Shuttle External Tank. These environments encompassed a myraid of potential flight cases which included nominal and dispersed trajectories launched from Kennedy Space Center (KSC) and Vandenberg and abort cases. Many iterations of environments have been produced during the evolution of the Space Shuttle system which required an analysis and assessment of each environment. A significant effort was expended in the analysis...

Topics: BOUNDARY LAYER TRANSITION, REVERSED FLOW, TURBULENT FLOW, WALL FLOW, FREE FLOW, GAS FLOW, PRESSURE...

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Aug 1, 2010
08/10

by
Okeefe, John A

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No Abstract Available

Topics: ASYMPTOTIC SERIES, FREQUENCIES, LOW FREQUENCIES, PERIODIC VARIATIONS, POSITION (LOCATION),...

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May 22, 2011
05/11

by
Kunz, Nan

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The purpose of this document is to describe the top level design goals for the cavity door. This is not a specification but only a guide to be used for deriving potential conceptual designs. The actual loads, insulation properties, factors of safety, etc. will be determined in the development phase in conjunction with the aircraft modifier in the same manner as the rest of the aircraft modifications. The primary addition that needs to be incorporated to the cavity door is a design that...

Topics: ANGLE OF ATTACK, ASYMMETRY, BOUNDARY LAYER SEPARATION, BOUNDARY LAYER TRANSITION, RADOMES, BOUNDARY...

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May 23, 2011
05/11

by
Chimento, Thomas C.; Doshay, David G.; Ross, Muriel D

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We cut serial sections through the medial part of the rat vestibular macula for Transmission Electron Microscopic (TEM) examination, computer-assisted three-dimensional (3-D) reconstruction, and compartmental modeling. The ultrastructural research showed that many primary vestibular neurons have an unmyelinated segment, often branched, that extends between the heminode, putative site of the Spike Initiation Zone ( SIZ ), and the expanded terminal(s) (calyx, calyces). These segments, termed the...

Topics: AEROTHERMODYNAMICS, NAVIER-STOKES EQUATION, TURBULENT BOUNDARY LAYER, LAMINAR BOUNDARY LAYER,...

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May 30, 2011
05/11

by
Markley, F. Landi

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The four-component quaternion has the lowest dimensionality possible for a globally nonsingular attitude representation, it represents the attitude matrix as a homogeneous quadratic function, and its dynamic propagation equation is bilinear in the quaternion and the angular velocity. The quaternion is required to obey a unit norm constraint, though, so Kalman filters often employ a quaternion for the global attitude estimate and a three-component representation for small errors about the...

Topics: ABLATION, THERMAL PROTECTION, SURFACE ROUGHNESS, BOUNDARY LAYER TRANSITION, LAMINAR BOUNDARY LAYER,...

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May 31, 2011
05/11

by
Gnoffo, Peter A.; Anderson, Brian P

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A ballute (balloon-parachute) is an inflatable, aerodynamic drag device for application to planetary entry vehicles. Ballutes may be directly attached to a vehicle, increasing its cross-sectional area upon inflation, or towed behind the vehicle as a semi-independent device that can be quickly cut free when the requisite change in velocity is achieved. The aerothermodynamics of spherical and toroidal towed ballutes are considered in the present study. A limiting case of zero towline length...

Topics: BOUNDARY LAYER TRANSITION, TURBULENT FLOW, WALL TEMPERATURE, TRANSIENT HEATING, SURFACE ROUGHNESS,...

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Jun 9, 2011
06/11

by
Williams, Peggy S

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The NASA F-15 Intelligent Flight Control System project team has developed a series of flight control concepts designed to demonstrate the benefits of a neural network-based adaptive controller. The objective of the team is to develop and flight-test control systems that use neural network technology to optimize the performance of the aircraft under nominal conditions as well as stabilize the aircraft under failure conditions. Failure conditions include locked or failed control surfaces as well...

Topics: SURFACE ROUGHNESS, REENTRY VEHICLES, GROUND TESTS, FLOW DISTRIBUTION, BOUNDARY LAYER TRANSITION,...

This report summarizes research conducted during the past three and a half years aimed at developing and testing a turbulence/transition model applicable to high-speed turbulent flows. The first two years of the project focused on fully turbulent flows, while emphasis shifted to boundary-layer development in the transition region during the final year and a half. This report includes a brief summary of research accomplished during the first three years and cites publications that describe...

Topics: DTIC Archive, Wilcox, David C, DCW INDUSTRIES INC LA CANADA CA, *TURBULENT FLOW, *BOUNDARY LAYER...

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May 31, 2011
05/11

by
Kory, Carol L.; Andro, Mont

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For the first time, a computational model has been used to provide a direct description of the effects of the traveling wave tube (TWT) on modulated digital signals. The TWT model comprehensively takes into account the effects of frequency dependent AM/AM and AM/PM conversion, gain and phase ripple; drive-induced oscillations; harmonic generation; intermodulation products; and backward waves. Thus, signal integrity can be investigated in the presence of these sources of potential distortion as...

Topics: AIRCRAFT CONFIGURATIONS, AEROELASTICITY, CIVIL AVIATION, REYNOLDS NUMBER, SUPERSONIC TRANSPORTS,...

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Jun 13, 2011
06/11

by
Kulkarni, Nilesh; Ippolito, Corey; Krishnakumar, Kalmanje; Al-Ali, Khalid M

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Adaptive control technology is developed for the inner-loop speed and steering control of the MAX Rover. MAX, a CMU developed rover, is a compact low-cost 4-wheel drive, 4-wheel steer (double Ackerman), high-clearance agile durable chassis, outfitted with sensors and electronics that make it ideally suited for supporting research relevant to intelligent teleoperation and as a low-cost autonomous robotic test bed and appliance. The design consists of a feedback linearization based controller...

Topics: BOUNDARY LAYER TRANSITION, FLIGHT TESTS, SPACE SHUTTLES, PROTUBERANCES, PREDICTIONS, DAMAGE...

The main points of recent theoretical and computational studies on boundary-layer transition and turbulence are to be highlighted. The work is based on high Reynolds numbers and attention is drawn to nonlinear interactions, breakdowns and scales. The research focuses in particular on truly nonlinear theories, i.e. those for which the mean-flow profile is completely altered from its original state. There appear to be three such theories dealing with unsteady nonlinear pressure-displacement...

Topics: NASA Technical Reports Server (NTRS), NONLINEARITY, BOUNDARY LAYER TRANSITION, NUMERICAL ANALYSIS,...

New facilities and test techniques afford research aerodynamicists many opportunities to investigate complex aerodynamic phenomena. For example, NASA Langley Research Center's National Transonic Facility (NTF) can hold Mach number, Reynolds number, dynamic pressure, stagnation temperature and stagnation pressure constant during testing. This is important because the wing twist associated with model construction may mask important Reynolds number effects associated with the flight vehicle....

Topics: NASA Technical Reports Server (NTRS), LUMINESCENCE, PAINTS, HEATING, MEASURING INSTRUMENTS, THERMAL...

Physically-based parameterizations of vertical mixed layer fluxes in ocean models characterize turbulent mixing at length scales smaller than the layer depth, but do not address the dynamics of unresolved submesoscale horizontal mixing processes below their O(0.1)-O(10) km horizontal resolution scale. Modeling work carried out as part of this AESOP DRI has focused on surface boundary layer horizontal mixing processes in regions of significant horizontal variability, as commonly found in frontal...

Topics: DTIC Archive, WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB, *OCEAN MODELS, *BOUNDARY LAYER FLOW,...

Experimental measurements have been made of the distance of transition to turbulence of the wake behind hypersonic spherical and blunted cone models at hypersonic speeds in a ballistic range. Transition distances behind blunt bodies were found to be independent of body shape, whereas a definite shape effect was observed for slender bodies. A single shape parameter was determined which successfully correlated all the slender body data. The transition process was found to be markedly different...

Topics: DTIC Archive, Wilson, L N, GM DEFENSE RESEARCH LABS SANTA BARBARACA, *AERODYNAMIC CONFIGURATIONS,...

Hypersonic Wake transition data over a range of reynolds numbers have been obtained over the past several years at many laboratories. In the present paper, the available experimental data is structured into three laws: The Law of the Far Wake, The Law of the Near Wake, and The Law of the Interpolation Regime. These three laws are then represented on a single Hypersonic Wake Transition Map. The Reynolds number is selected as the correlating parameter, where local conditions, characterizing the...

Topics: DTIC Archive, Goldburg, A, AVCO EVERETT RESEARCH LAB INC EVERETT MA, *WAKE, *HYPERSONIC FLOW,...

Wind tunnel investigations of three scale models were conducted to determine the effects of model scaling in the subsonic and transonic flow regimes. The models were 4.7-, 13-, and 17-percent scale F-15 fighter equivalent body models. The data were obtained at Mach numbers from 0.60 to 1.40 and free- stream Reynolds numbers from 1.0 to 5.3 million for model angles of attack from 0 to 5 deg. The results show that at subsonic Mach numbers the zero-lift pressure drag coefficient of the basic...

Topics: DTIC Archive, Reichenau, David E A, ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFB TN, *AIRCRAFT...

The BLT Prediction Tool ("BLT" signifies "Boundary Layer Transition") is provided as part of the Damage Assessment Team analysis package, which is utilized for analyzing local aerothermodynamics environments of damaged or repaired space-shuttle thermal protection tiles. Such analyses are helpful in deciding whether to repair launch-induced damage before re-entering the terrestrial atmosphere.

Topics: NASA Technical Reports Server (NTRS), AEROTHERMODYNAMICS, BOUNDARY LAYER TRANSITION, DAMAGE...

Viscous flow over discrete or distributed surface roughness has great implications for hypersonic flight due to aerothermodynamic considerations related to laminar-turbulent transition. Current prediction capability is greatly hampered by the limited knowledge base for such flows. To help fill that gap, numerical computations are used to investigate the intricate flow physics involved. An unstructured mesh, compressible Navier-Stokes code based on the space-time conservation element, solution...

Topics: NASA Technical Reports Server (NTRS), HYPERSONIC FLOW, VISCOUS FLOW, SURFACE ROUGHNESS, HYPERSONIC...

An experimental study has been conducted to assess the effects of compression pad cavities on the aeroheating environment of the Project Orion CEV heat-shield. Testing was conducted in Mach 6 and Mach 10 perfect-gas wind tunnels to obtain heating measurements in and around the compression pads cavities using global phosphor thermography. Data were obtained over a wide range of Reynolds numbers that produced laminar, transitional, and turbulent flow within and downstream of the cavities. The...

Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC HEATING, AUGMENTATION, COMPRESSIBILITY EFFECTS,...

Viscous Laminar-turbulent transition plays an important role in the design of the Mars Science Laboratory (MSL) entry vehicle. The lift-to-drag ratio required for the precision landing trajectory will be achieved via an angle of attack equal to 16 degrees. At this relatively high angle of attack, the boundary layer flow near the leeward meridian is expected to transition early in the trajectory, resulting in substantially increased heating loads. This paper presents stability calculations and...

Topics: NASA Technical Reports Server (NTRS), BOUNDARY LAYER TRANSITION, LAMINAR FLOW, CROSS FLOW,...

Efforts to design and operate hypersonic entry vehicles are constrained by many considerations that involve all aspects of an entry vehicle system. One of the more significant physical phenomenon that affect entry trajectory and thermal protection system design is the occurrence of boundary layer transition from a laminar to turbulent state. During the Space Shuttle Return To Flight activity following the loss of Columbia and her crew of seven, NASA's entry aerothermodynamics community...

Topics: NASA Technical Reports Server (NTRS), BOUNDARY LAYER TRANSITION, CORRELATION, HYPERSONIC BOUNDARY...

Direct numerical simulation is used to investigate the transition induced by threedimensional isolated roughness elements in a supersonic boundary layer at a free stream Mach number of 3.5. Simulations are performed for two different configurations: one is a square planform roughness and the other is a diamond planform roughness. The mean-flow calculations show that the roughness induces counter rotating streamwise vortices downstream of the roughness. These vortices persist for a long distance...

Topics: NASA Technical Reports Server (NTRS), SURFACE ROUGHNESS, BOUNDARY LAYER TRANSITION, SUPERSONIC...

Direct numerical simulation of acoustic radiation from a turbulent boundary layer in a cylindrical domain will be conducted under the flow conditions corresponding to those at the nozzle exit of the Boeing/AFOSR Mach-6 Quiet Tunnel (BAM6QT) operated under noisy-flow conditions with a total pressure p(sub t) of 225 kPa and a total temperature of T(sub t) equal to 430 K. Simulations of acoustic radiation from a turbulent boundary layer over a flat surface are used as a reference configuration to...

Topics: NASA Technical Reports Server (NTRS), SOUND WAVES, TURBULENT BOUNDARY LAYER, BOUNDARY LAYER...

There are many flows of practical importance where both Tollmien-Schlichting waves and Taylor-Goertler vortices are possible causes of transition to turbulence. The effect of fully nonlinear Taylor-Goertler vortices on the growth of small amplitude Tollmien-Schlichting waves is investigated. The basic state considered is the fully developed flow between concentric cylinders driven by an azimuthal pressure gradient. It is hoped that an investigation of this problem will shed light on the more...

Topics: NASA Technical Reports Server (NTRS), FLUID DYNAMICS, FLUID FLOW, GOERTLER INSTABILITY,...

The potential of laminar flow nacelles for reducing installed engine/nacelle drag was studied. The purpose was twofold: to experimentally verify a method for designing laminar flow nacelles and to determine the effect of installation on the extent of laminar flow on the nacelle and on the nacelle pressure distributions. The results of the isolated nacelle tests illustrated that laminar flow could be maintained over the desired length. Installing the nacelles on wing/pylon did not alter the...

Topics: NASA Technical Reports Server (NTRS), BOUNDARY LAYER TRANSITION, DRAG REDUCTION, LAMINAR FLOW,...

Flow visualization is used extensively in flight testing to determine aerodynamic characteristics such as surface flow direction and boundary layer state. Several visualization techniques are available to the aerodynamicist. Two of the most popular are oil flows and sublimating chemicals. Oil is used to visualize boundary layer transition, shock wave location, regions of separated flow, and surface flow direction. Boundary layer transition can also be visualized with sublimating chemicals. A...

Topics: NASA Technical Reports Server (NTRS), ACETONE, AERODYNAMIC CHARACTERISTICS, COATINGS, FLIGHT TESTS,...

A common airfoil model with the CAST 10-2/DOA-2 profile and 228 mm (9 inches) chord length was tested. The tests performed in NAE covered the Mach numbers from 0.3 to 0.8 and Reynolds numbers from 10 to 30 million. The model was tested with transition free and with transition fixed at 5 percent chord for both the upper and the lower surfaces. The data obtained were analyzed for the effects of Reynolds number, transition fixing and Mach number. The role of the boundary layer on the displacement...

Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC CHARACTERISTICS, AERODYNAMIC INTERFERENCE,...

The objective is to provide useful engineering formulations and to instill a modest degree of physical understanding of the phenomena governing convective aerodynamic heating at high flight speeds. Some physical insight is not only essential to the application of the information presented here, but also to the effective use of computer codes which may be available to the reader. Given first is a discussion of cold-wall, laminar boundary layer heating. A brief presentation of the complex...

Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC HEATING, BOUNDARY LAYER TRANSITION, COMPUTATION,...

A major goal of research on marine stratocumulus is to try to understand the processes that generate and dissipate them. One approach to studying this problem is to investigate the boundary layer structure in the vicinity of a transition from a cloudy to a cloud-free region to document the differences in structure on each side of the transition. Since stratiform clouds have a major impact on the radiation divergence in the boundary layer, the transition from a cloudy to a clear boundary layer...

Topics: NASA Technical Reports Server (NTRS), AERIAL PHOTOGRAPHY, BOUNDARY LAYER TRANSITION, BOUNDARY...

The extent to which the plume from a solar thermal rocket will impinge on the solar collector is studied by flow field analysis. Such interaction can adversely affect collector performance through fouling, excessive heat loading, or pressure loads that deform the delicate structures. The geometrical shape of the collector is such that only the flow from the nozzle boundary layer can reach it, but the thrust levels of interest lead to very viscous nozzle flows with thick boundary layers....

Topics: NASA Technical Reports Server (NTRS), FLOW DISTRIBUTION, JET IMPINGEMENT, MIRRORS, NOZZLE FLOW,...

A survey of infrared thermography for aerodynamics was made. Particular attention was paid to boundary layer transition detection. IR thermography flow visualization of 2-D and 3-D separation was surveyed. Heat transfer measurements and surface temperature measurements were also covered. Comparisons of several commercial IR cameras were made. The use of a recently purchased IR camera in the Ames Unitary Plan Wind Tunnels was studied. Optical access for these facilities and the methods to scan...

Topics: NASA Technical Reports Server (NTRS), BOUNDARY LAYER SEPARATION, BOUNDARY LAYER TRANSITION, HEAT...

Based on previous observations of glaze ice accretion on aircraft surfaces, a multizone model with distinct zones of different surface roughness is demonstrated. The use of surface roughness in the LEWICE ice accretion prediction code is examined. It was found that roughness is used in two ways: (1) to determine the laminar to turbulent boundary-layer transition location; and (2) to calculate the convective turbulent heat-transfer coefficient. A two-zone version of the multizone model is...

Topics: NASA Technical Reports Server (NTRS), CONVECTIVE HEAT TRANSFER, FLOW DISTRIBUTION, GLAZES, ICE, ICE...

Design and experimental analyses of unmanned entry research vehicles having high hypersonic L/D and high volume are described. Analytic parametric data are presented for two lifting body classes designated HLD-35 and FDL-5. Experimental aerodynamic and heat transfer data obtained from Arnold Engineering Development Wind Tunnels A, B, C, and F are compared with analytic data for the FDL-5 vehicle. Structure and subsystems are selected for performing unmanned hypersonic research with the vehicle.

Topics: DTIC Archive, Guard, Fred L, LOCKHEED-CALIFORNIA CO BURBANK, *LIFTING REENTRY VEHICLES, HEAT...

Contents: Measurement of Turbulent Skin Friction on a Slender Cone; Effect of High Heat Transfer Rates on Boundary Layer Transition; Body Scale Effects on the Aerodynamic Characteristics of Wakes (Including Edge Roughness); The Effect of Heat Transfer on the Aerodynamic Characteristics of Wakes.

Topics: DTIC Archive, Lankford, John L, NAVAL ORDNANCE LAB WHITE OAK MD, *REENTRY VEHICLES, *CONICAL...

The study describes an analytical solution of the nonsimilar laminar boundary layer with pressure gradient, variable wall temperature and continuous injection. The method consists of transforming the partial differential equations for momentum and enthalpy and then solving the transformed equations by assuming polynomial stream function and enthalpy profiles. Solutions obtained show very good agreement with exact numerical results. The solutions are obtained for flows over wedges as well as at...

Topics: DTIC Archive, Pavri, R E, CINCINNATI UNIV OH DEPT OF AEROSPACE ENGINEERING, *LAMINAR BOUNDARY...

A momentum-integral method for calculating the boundary-layer growth on slightly-blunted cones has been given in a previous paper by the writer. The method, which was applied to cones with fully laminar flow, is extended in the present paper to turbulent flow. In addition: (1) transition data on cones at hypersonic speeds are examined to show the great effect of slight nose blunting on interpretation of the results, (2) agreement between measured and calculated cone drag coefficients for fully...

Topics: DTIC Archive, NAVAL ORDNANCE LAB WHITE OAK MD, *BOUNDARY LAYER TRANSITION, *HYPERSONIC...

An experimental investigation of the laminar flow over a cone-cavity model with a rounded reattachment shoulder at zero angle of attack was conducted at M=5.4. For mass injection into the cavity at rates up to eight-tenths the boundary layer mass flow at separation, the pressure and heat transfer distributions along the surface were obtained, with emphasis on the reattachment zone. A simple empirical correlation was established between reattachment pressure and heat transfer peaks as a function...

Topics: DTIC Archive, Ginoux, Jean J, VON KARMAN INST FOR FLUID DYNAMICS RHODE-SAINT-GENESE (BELGIUM),...

A review is given of boundary layer stability and transition. The normal modes procedures as they apply to boundary layers are briefly reviewed and the mechanism of instability is discussed. It is shown how normal modes results may be used to give guidance regarding the factors affecting transition. Some remarks are made about the prediction of transition and about the fixing of transition. It is concluded that the process of transition from laminar to turbulent flow remains unsolved. However,...

Topics: DTIC Archive, Reshotko, Eli, CASE WESTERN RESERVE UNIV CLEVELAND OH DEPT OF AEROSPACE SCIENCES,...

Careful experiments on boundary layer transition conducted in low turbulence wind tunnels have resolved three stages in the breakdown of laminar flow into turbulence: in the first stage, two-dimensional oscillations, commonly referred to as TS waves, appear and propagate in the direction of the flow; in the second stage there appears a rapid three-dimensional deformation of the oscillatory flow; and in the brief third stage high frequency, small scale, quasi-random fluctuations appear and...

Topics: DTIC Archive, Bertolotti, Fabio P, VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG, *BOUNDARY...