The experimental survey of the flow field near the leading edge of a cooled, sharp flat plate parallel to a hypersonic stream of low density is discussed. Results consisting of impact pressure and hot-wire anemometer profiles plus surface pressures are analyzed and compared to recent theoretical results. Data are presented for viscous interaction parameters as high as 2.0.
Topics: DTIC Archive, ARO INC ARNOLD AFS TN, *FLAT PLATE MODELS, *HYPERSONIC CHARACTERISTICS, ANEMOMETERS,...
The equation of an infinite thin plate under the influence of point loads and mid-plane forces is developed. The properties of the function as the tension goes to zero or becomes large is investigated. This function is then used ot interpolate scattered data, giving the user the parameter of tension to give some control over overshoot when the surface has large gradients. Examples illustrating the behavior of the interpolation function are given. (Author).
Topics: DTIC Archive, Franke,R, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *TENSION, *SPLINES, LOAD...
Topics: DTIC Archive, Phelan, R M, CORNELL UNIV ITHACA NY, *LUBRICATING OILS, *JOURNAL BEARINGS, VISCOSITY,...
Drag reduction caused by ejecting additive solutions from a slot into a pure-water boundary layer on a flat plate was systematically studied. Results include drag measurements for a plane boundary, smooth and rough, with various openings of the slot and with various concentrations and discharges of the ejected additive solution. Conclusions were drawn on the additive requirement in external flows and on the ejection technique for an optimum drag reduction.
Topics: DTIC Archive, Wu, Jin, HYDRONAUTICS INC LAUREL MD, *BOUNDARY LAYER, *DRAG, WATER, POLYMERS,...
Van Driest's theory, which provides a continuous velocity and shear distribution for turbulent flow near a nonporous wall, is extended to turbulent flow near a porous wall. The new, modified theory enables the theoretical calculation of velocity profiles to be performed for a wider range of mass- transfer rates, and it gives good agreement with experimental data.
Topics: DTIC Archive, Cebeci, Tuncer, DOUGLAS AIRCRAFT CO LONG BEACH CA, *TURBULENCE, BOUNDARY LAYER, FLAT...
As part of a fundamental study of hypersonic wings, some detailed pressure distribution and heat transfer results were obtained over sections of the leading edge region of a blunt plate at sweep angles from zero to 75 degrees. The tests were carried out in a Helium hypersonic wind tunnel at Mach numbers from 7 to 17. Some effects of the apex or upstream boundary of the plate on the leading edge regions under study were determined at various stations along the leading edge. The leading edge...
Topics: DTIC Archive, HORSTMAN, C C, PRINCETON UNIV NJ, *HYPERSONIC CHARACTERISTICS, *WINGS, HEAT TRANSFER,...
The characteristics of general laminar flows around the edge of a semi-infinite flat plate are investigated on the basis of the complete NavierStokes equations. The solution of this singular and nonlinear problem is obtained in an exact and linear manner in the form of a double series around the edge. It permits a rigorous discussion of the properties of flows around an edge, which are of importance in the practical applications as well as in the theory of viscous and nonviscous fluid motions....
Topics: DTIC Archive, Lugt, Hans J, NAVAL WEAPONS LAB DAHLGREN VA, *EQUATIONS, FLAT PLATE MODELS, LAMINAR...
A flat plate experiences a transverse acceleration under the action of a pressure that also produces plastic yielding throughout the plate. Taylor instability is considered on the assumptions of a single degree of freedom, incompressible flow, and the Prandtl-Reuss constitutive equations in the limiting cases of (A) infinitesimal perturbations and (B) rigid-plastic flow (yield stress/shear modulus approaches O).
Topics: DTIC Archive, GENERAL DYNAMICS SAN DIEGO CA GENERAL ATOMIC DIV, *FLAT PLATE MODELS, ACCELERATION,...
Topics: DTIC Archive, Konotop,V V, FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OH, *INDUCTANCE,...
Topics: DTIC Archive, Panchenkov, A N, SCRIPTA TECHNICA INC WASHINGTON DC, *HYDROFOILS, VELOCITY,...
Topics: DTIC Archive, Smiley, Robert F, NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON DC,...
A theoretical solution is obtained for the problem of the compressive buckling of flat rectangular Metalite type sandwich plates with simply supported loaded edges and clamped unloaded edges. The solution is based upon the general small-deflection theory for flat sandwich plates developed in NACA TN No l526. Good agreement is found between the present results and those of Forest Products Laboratory Rep. No. l583. A comparison of computed arid experimental buckling stresses of sandwich plates...
Topics: DTIC Archive, Seide, Paul, NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON DC, *BUCKLING,...
Topics: DTIC Archive, Moulic, E S, CALIFORNIA UNIV BERKELEY INST OF ENGINEERING RESEARCH, *SKIN FRICTION,...
Body shapes, including axisymmetric and three dimensional, have been developed to minimize wave drag. The von Karman ogive and the area rule are examples. Similar work has not been accomplished for optimum shapes with propulsion. Propulsion can be divided
Topic: *DRAG, *AIRFRAMES, *AIRCRAFT ENGINES, THERMAL ANALYSIS, TURBOJET EXHAUST NOZZLES, PLUG NOZZLES,...
Topics: DTIC Archive, Bogacheva, A A, FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OH, *SLIP FLOW, *FLAT...
Design methods are developed for determining aerodynamic control effectiveness at hypersonic speeds along body surface. Pressure and heat transfer distributions in separated regions due to aerodynamic control deflection are described in terms of characteristic magnitudes and distance parameters by semiempirical correlations. The forms of these correlations are inferred from theory and experimental data. Using these correlations, pressure distribution in the separated region over a deflected...
Topics: DTIC Archive, Ehrlich, Carl F, LOCKHEED-CALIFORNIA CO BURBANK, *HYPERSONIC CHARACTERISTICS,...
A Structural Model of the dynamic response of functionally graded plates exposed to a free in-air blast with simply supported boundary conditions has been presented. As the volume fraction of ceramic increases, the deflections become smaller with higher frequencies in contrast to metal phase. The symmetric construction due to being stiffer has smaller deflections and higher frequencies as compared to the asymmetric construction. For a fixed compressive edge load, as the metal concentration...
Topics: DTIC Archive, ARMY TANK AUTOMOTIVE RESEARCH DEVELOPMENT AND ENGINEERING CENTER WARREN MI, *METAL...
This study investigated materials and processes for fundamental improvements in flat-plate solar collector cost and performance. The goal was to develop a process for direct conversion of inexpensive raw materials into a completed solar collector unit without labor intensive assembly operations. It was thought that materials carefully matched to the process and 'end-use' environment would substantially reduce collector costs, as compared to conventional industry practice. jg p7
Topics: DTIC Archive, Rhodes, Richard O., FAFCO INC MENLO PARK CA, *CONVERSION, *POLYMERS, *EXTRUSION,...
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Body shapes, including axisymmetric and three dimensional, have been developed to minimize wave drag. The von Karman ogive and the area rule are examples. Similar work has not been accomplished for optimum shapes with propulsion. Propulsion can be divided
Topic: *DRAG, *AIRFRAMES, *AIRCRAFT ENGINES, THERMAL ANALYSIS, TURBOJET EXHAUST NOZZLES, PLUG NOZZLES,...
This report presents the results of a program which investigated alternatives to flat-plate canopy concepts to control helicopter visual detection cues and to reduce internal reflections. During the program, full-scale soft mockups were constructed, tested, and evaluated. (Author)
Topics: DTIC Archive, Blewitt,Stephen J, BOEING VERTOL CO PHILADELPHIA PA, *HELICOPTERS, *CANOPIES, *GLINT,...
The work gives the results of an experimental investigation of acoustic emission of cavities of diverse configuration on a flat plate in a supersonic streamline flow of air at M = 1.7. From the investigation it is concluded that travelling waves on the interface result from the appearance of natural oscillations in a system consisting of the interface and the volume of air in the depression.
Topics: DTIC Archive, Morozov, M G, FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSONAFB OH, *AERODYNAMIC NOISE,...
Separation mitigation using asymmetric dielectric barrier discharges is studied by considering the neutral gas flow past a flat plate at an angle of attack. A self-consistent plasma actuator model is employed to couple the electric force field to the momentum of the neutral gas. The equations governing the motion of electrons, ions and neutrals are solved with Poisson's equation to study effective control of flow separation. The impact of select parameters such as amplitude of the excitation,...
Topics: DTIC Archive, KETTERING UNIV FLINT MI, *ACTUATORS, *BARRIERS, *CONTROL, *DIELECTRICS, *PARAMETERS,...
The present paper deals with an experimental study of the viscous- inviscid interaction occurring in a corner region under hypersonic, low density, free stream conditions. The tests were conducted in the Mach 11.8 hypersonic tunnel at PIBAL over a range of free stream Reynolds numbers between 0.15 x 10 to the 6th and 0.50 x 10 to the 6th/ft. The model consists of two sharp edged plates mounted at an angle of 90 degrees with respect to each other and with normal leading edges. Data obtained...
Topics: DTIC Archive, POLYTECHNIC INST OF BROOKLYN NY DEPT OF AEROSPACE ENGINEERING AND APPLIED MECHANICS,...
Topics: DTIC Archive, Wade, R B, CALIFORNIA INST OF TECH PASADENA, *HYDRODYNAMICS, *HYDROFOILS,...
Exact solutions for the transient temperature distribution and the stored energy in an infinite plate of finite thickness are presented for the case of different convective environments at each face of the plate. The solution is general and contains numerous limiting cases, including that of steady state. Eigenvalues are given for many combinations of the system Biot numbers for the initial response period. An example is presented to illustrate the application of the solution to the practical...
Topics: DTIC Archive, Ybarrondo, L J, ARO INC ARNOLD AFS TN, *FLAT PLATE MODELS, *THERMODYNAMICS, BOUNDARY...
Results are presented of an investigation conducted in the Naval Ordnance Laboratory's Supersonic Tunnel No. 2 to measure the weight flow of air through various sized holes in a flat plate exposed to a flow parallel to the plane of the plate. These data were obtained at free-stream Mach numbers of 0.50 and 1.53 for various static pressure ratios across the flat plate. Results indicated that the measured weight flow rate decreases as the parallel flow Mach number increases. Increasing the...
Topics: DTIC Archive, Kalivretenos, C A, NAVAL ORDNANCE LAB WHITE OAK MD, *AERODYNAMIC DRAG, *FLAT PLATE...
As an application of the concepts in NACA TN 2541, the problem of turbulent boundary layer over a flat plate in compressible flow is treated. The dissipation term in the energy equation, often neglected, is first carefully studied and found to be of importance. In the differential equations governing the fluctuations, the lower-frequency components of all quantities are regarded to participate in an equilibrium in accordance with the similarity concept. After proper linearization, a set of...
Topics: DTIC Archive, Lin, C C, MASSACHUSETTS INST OF TECH CAMBRIDGE, *TURBULENT BOUNDARY LAYER,...
The method of Physical Optics, the Geometrical Theory of Diffraction and the Uniform Geometrical Theory of Diffraction are applied here to electromagnetic scattering from flat plates and rectangular cylinders. The results are compared with experimental measurements to establish the domains of validity of the theoretical techniques. Keywords include: Optics; Diffraction; Electromagnetic scattering; and Backscattering. (Australia).
Topics: DTIC Archive, Anderson, W. C., ELECTRONICS RESEARCH LAB ADELAIDE (AUSTRALIA), *BACKSCATTERING,...
Topics: DTIC Archive, Li, Ting-Yi, RAND CORP SANTA MONICA CA, *FLAT PLATE MODELS, *LAMINAR BOUNDARY LAYER,...
Measurements of the mean velocity and the normal and tangential stresses in the wake of a rough flat plate near a free water surface are presented. The various distributions are compared with similar measurements taken in the wake of the plate when submerged in an effectively infinite fluid. The results reveal striking differences in the manner in which the wake evolves in the two instances. In contrast to the plane wake in an infinite fluid the present experiments show that in the proximity of...
Topics: DTIC Archive, Swean,T F , Jr, NAVAL RESEARCH LAB WASHINGTON DC, *WAKE, *FLAT PLATE MODELS, SHEAR...
The problem of theoretically describing forced laminar flow over a flat plate is revisited. For the last hundred years it has been assumed that the Blasius solution model applies to this case. However, upon close review it is found that the Blasius model has a serious problem in that the Blasius model assumes that the pressure gradient on the plate in the flow direction is zero. In fact what one expects is that a pressure gradient develops as fluid is displaced from the plate due to the...
Topics: DTIC Archive, AIR FORCE RESEARCH LAB HANSCOM AFB MA SENSORS DIRECTORATE/ELECTROMAGNETICS TECHNOLOGY...
Tests were conducted at Mach numbers 2.5 to 4.0 to investigate the effects of cylindrically blunted fins on the flow over a flat plate at zero angle of attack. The free-stream Reynolds number, based on the distance from the blunt fin to the flat plate leading edge, ranged from 2,800,000 to 4,700,000. Pitot pressure profiles were obtained in the fin-induced flow separation region. Increasing the thickness of the fin was found to increase the size of the three dimensional separation area....
Topics: DTIC Archive, Lucas, Ernest J, ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFB TN, *FINS, *FLOW...
Various edge diffraction theories are examined for the calculation of electromagnetic scatter from flat plates. The theories are compared, their shortcomings are discussed, and possible remedies are briefly described. Keywords: Physical theory of diffraction, Incremental length diffraction coefficient, Method of equivalent currents.
Topics: DTIC Archive, Gordon, W B, NAVAL RESEARCH LAB WASHINGTON DC, *DIFFRACTION, *ELECTROMAGNETIC...
Two moddls of bonded discontinuous plane potential flows, or cavities, are presented and discussed. The first, satisfies all the mathematical conditions on a flow with free boundaries and non-zero cavitation number. The free streamlines in this model reverse direction at the rear of the cavity to form a jet extending theoretically 'through' the obstacle to infinity. The second theory artificially introduces another obstacle which closes the cavity at its rear. The mathematical solutions to the...
Topics: DTIC Archive, Gilbarg, D, NAVAL ORDNANCE LAB WHITE OAK MD, *POTENTIAL FLOW, *CAVITATION, VELOCITY,...
A theory is described which can be used to predict accurately the skin friction drag of surfaces with uniform grain-type roughness. The roughness does not necessarily have to extend to the leading edge of the surface for an accurate calculation to be made. Uniform surface roughness composed of spherical beads does not affect the boundary layer in a manner significantly different from grain-type roughness, provided that the grains and the spheres are bonded to the surface in a similar manner....
Topics: DTIC Archive, Fenter, Felix W, TEXAS UNIV AT AUSTIN DEFENSE RESEARCH LAB, *SUPERSONIC FLOW,...
The long-term goals of this research are to develop the control methodology for active cloaking of underwater assets and the initial hardware concepts to test the proposed cloaking approach. This work is a natural extension of ONR Project N00014-02-1-0211 (Optical Variability and Bottom Classification in Turbid Waters: HyMOM Predictions of the Light Field in Ports and Beneath Ship Hulls) where the perceptibility of underwater assets was modeled. The initial objective of this work is to extend...
Topics: DTIC Archive, UNIVERSITY OF SOUTH FLORIDA SAINT PETERSBURG COLL OF MARINE SCIENCE, *CAMOUFLAGE,...
This article features graphs and curves on the heating and cooling time of spherical bodies, cylinders, and plates so that these developments can be easily traced. In looking at these results, we must keep in mind that many tasks arising in furnace and heating technology, metal-working and metal improvement can be traced back to the heating and cooling of these simple bodies.
Topics: DTIC Archive, Groeber, Heinrich, ARMY BIOLOGICAL LABS FREDERICK MD, *CYLINDRICAL BODIES, HEAT...
Heat transfer rates and pressure distributions on three basic shapes were investigated at a nominal Mach number of 8 and free-stream Reynolds numbers from 0.43 to 3.4 million per foot. The models were a 0.4-in. nose radius, spherically blunted, 15-deg half-angle cone; two flat plate models with 0. 10-in. and 0. 50-in. cylindrical blunting; and a modified leading-edge plate with auxiliary planes to produce changing body shape within the elliptic flow region. The tests produced data showing the...
Topics: DTIC Archive, RHUDY, J. P., ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFS TN, *HEAT TRANSFER,...
The report is an engineering guide to the use of the Dyer method of manual computation and to several computer programs for determining turbulence- induced vibration and radiation of finite plates in air and in water. Both simple and clamped boundary conditions are treated. The Dyer method and the computer programs are presented in a series of appendixes: Bolt Beranek and Newman manual method; Boeing program I; Electric boat program; Underwater sound laboratory program; Boeing program II -...
Topics: DTIC Archive, Leibowitz, Ralph C, DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER...
In electromagnetic armor, a shaped charge jet is disrupted when a large current is passed through it while the jet is in contact with two parallel flat plates. For the current to increase as quickly as possible to an effective level, the inductance of the circuit must be controlled or at least known. This inductance, however, depends on the position of the current connections to the plates and the position of the shaped charge jet. A method to calculate this inductance is presented, which is...
Topics: DTIC Archive, Hummer, Charles R, ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD, *MAGNETIC FIELDS,...
Boundary-layer parameters and frictional resistance formulas for either laminar or turbulent flow are derived for flat plates in power-law non- Newtonian fluids. The results for laminar flow are based on the known velocity profiles for pipe flow, whereas those for turbulent flow are based on the application of similarity laws.
Topics: DTIC Archive, Granville, Paul S, DAVID TAYLOR MODEL BASIN WASHINGTON DC, *BOUNDARY LAYER CONTROL,...
A procedure is described for monitoring the microfracturing activity in ice plates subjected to constant loads. Sample time records of freshwater ice plate deflections as well as corresponding total acoustic emission activities are presented. The linear elastic, as well as viscoelastic, response for a simply supported rectangular ice plate is given. Suggested future work using the above procedure is discussed. (Author)
Topics: DTIC Archive, Xirouchakis,P C, COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH, *ICE BREAKUP,...
A procedure is described for monitoring the microfracturing activity in ice plates subjected to constant loads. Sample time records of freshwater ice plate deflections as well as corresponding total acoustic emission activities are presented. The linear elastic, as well as viscoelastic, response for a simply supported rectangular ice plate is given. Suggested future work using the above procedure is discussed. (Author)
Topics: DTIC Archive, Xirouchakis,P C, COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH, *ICE BREAKUP,...
A novel visualization technique that utilizes fluorescent dye excited by a sheet of laser light is employed to study turbulent spots evolving in an unstable laminar boundary layer. The large growth rates of the spot in the spanwise direction cannot be explained by classical entrainment. It is suggested that a new mechanism, termed 'destabilization,' accounts for the larger growth rates. Growth by destabilization appears to be the result of the turbulence inducing perturbation into the nearby...
Topics: DTIC Archive, Gad-el-Hak,Mohamed, FLOW RESEARCH CO KENT WA, *TURBULENCE, *BOUNDARY LAYER...
A procedure is described for monitoring the microfracturing activity in ice plates subjected to constant loads. Sample time records of freshwater ice plate deflections as well as corresponding total acoustic emission activities are presented. The linear elastic, as well as viscoelastic, response for a simply supported rectangular ice plate is given. Suggested future work using the above procedure is discussed. (Author)
Topics: DTIC Archive, Xirouchakis,P C, COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH, *ICE BREAKUP,...
Following closely E. Polhausen's solution for the laminar temperature field at the flat plate in longitudinal flow, formulas are derived which permit calculation of the velocity and temperature field for variable properties by means of an integral equation and an iteration method based on this equation. Accordingly, the following cases were solved: By assuming that only viscosity varies with temperature and that the remaining properties are constant, the velocity and temperature fields were...
Topics: DTIC Archive, RAND CORP SANTA MONICA CA, *HEAT TRANSFER, *LAMINAR BOUNDARY LAYER, *DIFFUSION,...
Topics: DTIC Archive, Aiello, Gennaro F, POLYTECHNIC INST OF BROOKLYN NY, *TURBULENT BOUNDARY LAYER, *BLUNT...
A novel visualization technique that utilizes fluorescent dye excited by a sheet of laser light is employed to study turbulent spots evolving in an unstable laminar boundary layer. The large growth rates of the spot in the spanwise direction cannot be explained by classical entrainment. It is suggested that a new mechanism, termed 'destabilization,' accounts for the larger growth rates. Growth by destabilization appears to be the result of the turbulence inducing perturbation into the nearby...
Topics: DTIC Archive, Gad-el-Hak,Mohamed, FLOW RESEARCH CO KENT WA, *TURBULENCE, *BOUNDARY LAYER...
Topics: DTIC Archive, Eagleson, P S, MASSACHUSETTS INST OF TECH CAMBRIDGE HYDRODYNAMICS LAB, *VIBRATION,...
A novel visualization technique that utilizes fluorescent dye excited by a sheet of laser light is employed to study turbulent spots evolving in an unstable laminar boundary layer. The large growth rates of the spot in the spanwise direction cannot be explained by classical entrainment. It is suggested that a new mechanism, termed 'destabilization,' accounts for the larger growth rates. Growth by destabilization appears to be the result of the turbulence inducing perturbation into the nearby...
Topics: DTIC Archive, Gad-el-Hak,Mohamed, FLOW RESEARCH CO KENT WA, *TURBULENCE, *BOUNDARY LAYER...
