Topics: Radio Program, Aerodynamics, Latin American studies, Shock waves, Latin America, Aerospace...
The objective of this work was to examine the way in which an acceleration wave propagates in a randomly layered nonlinear medium in which the material constants vary stochastically from layer to layer. Furthermore the problem, although formulated as a one-dimensional configuration, was modified to describe propagation in a bar in which there is a slowly changing cross-sectional area. Thus the analysis may be applied to formed charges which have an axis of symmetry and a slowly varying...
Topics: DTIC Archive, Jeffrey,Alan, DELAWARE UNIV NEWARK APPLIED MATHEMATICS INST, *MATHEMATICAL MODELS,...
The electromagnetic velocity (EMV) gage was used to investigate particle velocity vs time and peak particle velocity vs distance at several points in PMMA (polymethylmethacrylate) in the donor-gap arrangement of the NOL Large Scale Gap Test. The results obtained by the method agree favorably with previously measured peak particle velocities for gap distances from the HE-PMMA interface between 10 and 25 mm. At closer distances the particle velocity-time records are in good relative agreement...
Topics: DTIC Archive, Edwards, David J, NAVAL ORDNANCE LAB WHITE OAK MD, *MEASURING INSTRUMENTS,...
4
4.0
texts
eye 4
favorite 0
comment 0
xii, 346 p. : 24 cm
Topics: Differential equations, Hyperbolic -- Congresses, Shock waves -- Mathematics -- Congresses
Topics: DTIC Archive, DAVISON, ELMER H., NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH GLENN...
Contents: Measuring of Stark broadening of lines from light elements; UV radiation from shock-heated plasmas; Collisionless plasma shockwave experiment; Plasma diagnostics by light scattering.
Topics: DTIC Archive, MARYLAND UNIV COLLEGE PARK DEPT OF PHYSICS AND ASTRONOMY, *PLASMAS(PHYSICS),...
Volume V, the final volume of this series, compares the results obtained by photogrammetry of smoke-puff particle flow tracers in four experiments (DIPOLE WEST Shots 8 to 11) involving the simultaneous detonation of pairs of 1080-lb (490-kg) Pentolite charges. In Shots 8 and 11, one charge was at a height of 25 feet (7.6m) above the ground, and the second charge was 50 feet (15.2m) above the first. The corresponding distances for Shots 9 and 10 were 15 feet (4.6m) and 30 feet (9.2m). For Shots...
Topics: DTIC Archive, Dewey,J M, GENERAL ELECTRIC CO ALBUQUERQUE N MEX TEMPO, *PARTICLE TRAJECTORIES,...
A computational study has been conducted for high-speed reacting flows relevant to munition problems, including shock-induced combustion and gun muzzle blast. The theoretical model considers inviscid and viscous flows, multi-species, finite rate chemical reaction schemes, and turbulence. A range of hydrogen and oxygen reaction mechanisms are evaluated for the shock-induced combustion problem. Characteristics of the mechanisms such as the induction time, heat release, and the second explosion...
Topics: DTIC Archive, Clutter, James K., FLORIDA UNIV GAINESVILLE DEPT OF AEROSPACE ENGINEERING MECHANICS...
Topics: DTIC Archive, Yutkin, L A, FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OH, *EXTRUSION, *PLASTICS,...
Based on plate sheared interference photographs taken of vapor plumes produced by coupling 1.06 micron length pulse Nd:glass laser and LY12 aluminium targets, measurements were made that shock wave speeds in air for t<50 microsec were approximately 473m/s and vapor plume front diffusion speeds were approximately 162m/s. Making use of relevent thermodynamic characteristic equation sets associated with vapor plume plasma, maximum values obtained for ion density, ion temperature, degree of...
Topics: DTIC Archive, Yonghua, Yuan, NATIONAL AIR INTELLIGENCE CENTER WRIGHT-PATTERSON AFB OH, *PLASMA...
This document represents the proceedings of a symposium. The Interaction of Non-Nuclear Munitions with Structures, U. S. Air Force Academy, Colorado, May 10-13, 1983. The symposium was sponsored by the following U. S. Air Force agencies: Armament Laboratory, Eglin AFB, FL; Engineering and Services Laboratory, Tyndall AFB, FL; Office of Scientific Research, Bolling AFB, DC; Weapons Laboratory, Kirtland AFB, NM. The symposium was coordinated through the University of Florida Graduate Engineering...
Topics: DTIC Archive, Ross, C. A., FLORIDA UNIV EGLIN AFB GRADUATE ENGINEERING CENTER, *SYMPOSIA,...
The Air Force Weapons Laboratory attempted to make 100 time-of-arrival measurements on Pre-DIRECT COURSE. With an 88 percent success rate, the detonation wave propagation within the charge was measured. The top and bottom hemispheres detonated at two different rates. However, the detonation velocities were well within the existing data base for Ammonium-Nitrate Fuel Oil charges. One large jet was observed on the charge but its location should not have caused any problems for ground level...
Topics: DTIC Archive, Guice,R L, AIR FORCE WEAPONS LAB KIRTLAND AFB NM, *Detonation waves, *Explosive...
Interplanetary shock waves (ISWs) propagating through the solar wind can collide with the earth's bow shock, resulting in a series of new shocks, contact discontinuities, and rarefaction waves which interact to effectively move the bow shock and magnetopause toward the earth. A one dimensional MacCormack predictor corrector algorithm with Flux Corrected Transport (FCT) was developed to model the ISW bow shock and magnetopause interactions, and to numerically predict their propagation speeds...
Topics: DTIC Archive, Olson, William A., AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH, *SHOCK WAVES, *BOW...
A basic theory of weak normal shock - turbulent boundary layer interactions is given for two-dimensional non-separating flows including mass transfer across the wall throughout the interaction region. Even small amounts of suction are found to significantly reduce both the streamwise scale and thickening effect of the interaction and delay the onset of separation. This is shown to be a consequence of the large mass transfer effect on the shape of the incoming boundary layer Mach number profile...
Topics: DTIC Archive, Inger,G R, VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG DEPT OF AEROSPACE AND...
This report documents the development of a closed form solution to the idealized borehole pressuremeter problem in linear elastic transverse isotropic media. The borehole was assumed to be infinitely long and pressurized by a static pressure. The mathematical equations for the distribution of stresses and displacements anywhere around the borehole are derived and incorporated into the computer program BOREHOLE. The solution is relevant to the field determination of constitutive properties for...
Topics: DTIC Archive, Baladi ,George Y, ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MISS,...
The hybrid finite difference code developed by MacCormack was applied to the investigation of transonic normal-shock turbulent boundary layer interactions. The computations were performed for the half plane of a symetric two dimensional duct by establishing a symmetry boundary condition at the upper boundary. Both first and second order center line boudnary conditions were imposed with no measurable difference observed. A two-point linear extrapolation of the primative variable was...
Topics: DTIC Archive, Keel,Lowell C, AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING,...
Shock tubes and high explosives were used to produce blast waves of various pressure-time patterns in order to study their biological effects. Data obtained from these experiments showed that, against a reflecting surface, the LD50 reflected pressure for any given species remained fairly constant at the 'longer' durations and then rose sharply at the 'shorter' times. For dogs and goats, 'long' durations were beyond 20 msec and for mice, rats, guinea pigs, and rabbits, beyond 1 to 3 msec. At the...
Topics: DTIC Archive, Richmond, Donald R, LOVELACE FOUNDATION FOR MEDICAL EDUCATION AND RESEARCH...
Recent investigations on groundshock phenomena indicate that the dynamic response of certain non-linear (locking) media may approximate the behavior of cohesive granular soils and porous rock under high pressures. The theory of wave propagation in such materials should have application to the design of underground shelters at very high pressure levels and may shed some addi tional light, by these relatively simple means on problems associated with phenomena near ground zero, in case of surface...
Topics: DTIC Archive, Weidlinger, Paul, MITRE CORP BEDFORD MA, *GROUND SHOCK, *WAVE PROPAGATION, DYNAMIC...
With the advent of large-scale high-speed computing machines, it has become feasible to solve certain supersonic flow problems by numerical methods using the exact hydrodynamical equations instead of resorting to linearization or graphical methods. This report describes in detail one such numerical method; namely, an efficient form of the method of characteristics. Characteristic equations are derived for supersonic, steady, inviscid, isoenergetic flows in terms of a variety of dependent...
Topics: DTIC Archive, Clippinger, R F, ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD, *BODIES OF...
The response of solids composed of large molecules, to the rapid deposition of a large amount of energy was studied experimentally and theoretically. Laser equipment capable of inducing a solid state explosion, and studying, via ultrafast microscopy, and a variety of nonlinear optical techniques, was constructed, and used to investigate the behavior of a variety of solid materials on times ranging from 2 picoseconds (trillionths of a second) to seconds. The theory of statistical mechanics, and...
Topics: DTIC Archive, Dlott, Dana D, ILLINOIS UNIV AT URBANA DEPT OF CHEMISTRY, *SOLID STATE ELECTRONICS,...
A small conical shock tube is being used to provide an inexpensive alternative to standard explosive shock tests presently performed in open water at a commercial testing facility. The conical geometry was chosen because it represents a small solid angle segment of the spherically expanding field in open water. The charge required to produce a specified shock-wave pressure in open water is reduced by the solid angle. The test transducer is mounted to a piston located in a cylindrical chamber at...
Topics: DTIC Archive, Poche, Lynn B, TRI/TESSCO INC AUSTIN TX, *PRESSURE TRANSDUCERS, *PRESSURE...
We examine the onset timing of solar energetic particles (SEPs) in the large ground-level event (GLE) of 1977 November 22 as observed from six spacecraft at four distinct solar longitudes. In most cases, it was possible to use velocity dispersion of the energetic protons to fix the solar particle release (SPR) time and the path-length traveled by the initial particle burst from each solar longitude. We find that the SPR times do depend upon solar longitude, being earliest for spacecraft that...
Topics: NASA Technical Reports Server (NTRS), SOLAR LONGITUDE, ENERGETIC PARTICLES, VELOCITY DISTRIBUTION,...
Reducing or eliminating the operational restrictions of supersonic aircraft over populated areas has led to extensive research at NASA. Restrictions were due to the disturbance of the sonic boom, caused by the coalescence of shock waves formed off the aircraft. Recent work has been performed to reduce the magnitude of the sonic boom N-wave generated by airplane components with focus on shock waves caused by the exhaust nozzle plume. Previous Computational Fluid Dynamics (CFD) analysis showed...
Topics: NASA Technical Reports Server (NTRS), EXHAUST NOZZLES, NOZZLE FLOW, PLUMES, SUPERSONIC AIRCRAFT,...
Using the concept of intercepting orbits from a pair of Space Station serviced free flyers, a class of impact and shock wave experiments pertinent to planetary science can be performed. One proposed free flying vehicle is an impactor dispensor, and the second is the impact laboratory. How collision is achieved by utilizing essentially twice orbital velocity is demonstrated. The impactor dispensor contains a series of small flyer plates or other projectiles which are launched into the trajectory...
Topics: NASA Technical Reports Server (NTRS), EXPERIMENT DESIGN, HYPERVELOCITY IMPACT, HYPERVELOCITY...
A series of inlet analysis codes (2-D, axisymmetric, 3-D) were developed which can analyze complicated flow through complex inlet geometries in a reasonably efficient manner. The codes were verified and are being used extensively to analyze practical inlet geometries both at Langley as well as industries. Newly installed VPS 32 computer will allow more complex configurations to be analyzed. Scalar FORTRAN versions are available to increase transportability of the codes for use on other Scalar...
Topics: NASA Technical Reports Server (NTRS), CODING, COMPUTATIONAL FLUID DYNAMICS, INLET FLOW,...
Although there is adequate information on larger objects in low Earth orbit, specifically those objects larger than about 10 cm in diameter, there is little direct information on objects from this size down to 1 mm. Yet, this is the sized regime where objects acting as projectiles represent the ability to seriously damage or destroy a functioning spacecraft if they collide with it. The observed consequences of known collisional breakups in orbit indicates no significant momentum transfer in the...
Topics: NASA Technical Reports Server (NTRS), EARTH ORBITAL ENVIRONMENTS, EARTH ORBITS, HYPERVELOCITY...
An experimental study of open cavity flow has been made in a high Reynolds number, Mach 5 turbulent boundary layer. The majority of measurements made were of fluctuating wall pressures. The objectives were: (1) examine how effective changes in front and rear wall geometry were at attenuating the pressure oscillations, (2) explore how impingement of a shock wave (variable strength and position) the cavity flow, and (3) how stores (different geometries and positions) affected the cavity flow. In...
Topics: DTIC Archive, Dolling, D. S., TEXAS UNIV AT AUSTIN DEPT OF AEROSPACE ENGINEERING AND ENGINEERING...
In this collaborative effort on shock initiation in solids, advances were made in fundamental concepts and methods of investigation. A new theory was developed for shock-induced vibrational excitation, based on translation to vibration energy conversion. The key novelty of this work is the treatment of multiple correlated impulsive forces acting coherently on the internal degrees of the molecule as the shock wave passes. This theory is in excellent agreement with explicit simulations. The...
Topics: DTIC Archive, Apkarian, Ara V, CALIFORNIA UNIV IRVINE DEPT OF CHEMISTRY, *SHOCK WAVES, *EXPLOSIONS,...
Small, bare charges were detonated inside an M59 armored personnel carrier (APC) in an attempt to simulate the complex blast waves generated by the jets from shaped-charge warheads penetrating into armored vehicles. Anesthetized sheep were placed inside the APC at 91- and 122-cm ranges from 57- or ll3-g pentolite charges. Pressure-time was measured by pressure transducers either mounted on the animals or free standing at comparable ranges on the opposite side of the vehicle. In general, the...
Topics: DTIC Archive, Richmond, Donald R, LOS ALAMOS NATIONAL LAB NM LIFE SCIENCES DIV, *PRESSURE...
Calculations performed to date have produced no significant enhancement of teleseismic ground motion from a multiple shot array. This was true in spite of the fact that the near source fracture pattern from the array differed significantly from that produced by a spherically symmetric explosion source. Fairly large perturbations in the seismic radiation pattern did appear but at frequencies outside the teleseismic band. Enhanced tension failure did occur in the multiple shot calculation....
Topics: DTIC Archive, Cherry, J T, Bache, T C, Wray, W O, Masso, J F, SYSTEMS SCIENCE AND SOFTWARE LA JOLLA...
The Kirkwood-Brinkley shock propagation theory is used to obtain peak pressure-distance curves for Pentolite and TNT. The curve for Pentolite obtained by using the calculated initial pressure and flow energy at the charge surface as initial values is in excellent agreement with experiment for distances greater than 1.75 charge radii. The curve for TNT obtained by using some approximate values of the peak pressure and energy at the charge surface is in excellent agreement with some recent...
Topics: DTIC Archive, Shear, Ralph E, ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD, *SHOCK WAVES,...
Penetration of sound into a body of water from a simulated airborne sonic boom was measured in an acoustically scaled experiment. Dynamite caps were used to produce spherically spreading N-waves which impinged upon the water. Microphones at the water surface and hydrophones at various shallow depths were used to measure the exponentially attenuating penetration of the airborne pressure field into the water, under total reflection conditions. Agreement between the scaled experimental...
Topics: DTIC Archive, Waters, John F, HYDROSPACE RESEARCH CORP ROCKVILLE MD, *CIVIL AVIATION, *SEA WATER,...
As a result of a nuclear, chemical, or biological attack by the enemy, unprotected food and drinking products may be contaminated. Their use will severely infect and poison people. The report discusses various ways of protecting food from the above effects using different types of packaging.
Topics: DTIC Archive, Borovikov, A, ARMY FOREIGN SCIENCE AND TECHNOLOGY CENTER CHARLOTTESVILLE VA,...
The problem of supersonic and hypersonic flow past blunt bodies at small angles of attack is considered. Two-dimensional asymmetric as well as three-dimensional flow is analyzed. The method of analysis is an inverse one, that is, the shock-wave shape and free stream conditions are known, and the corresponding body shape and flow field are determined. Solutions at zeroANGLE OF ATTACK ARE OBTAINED AS A SPECIAL CASE OF THE GENERAL PROBLEM. Results at zero angle are obtained for shock waves that...
Topics: DTIC Archive, SWIGART, RUDOLPH J, STANFORD UNIV CA, *SHOCK WAVES, *BLUNT BODIES, THEORY,...
Deformation of a granite, tonalite and limestone in a plane shock wave was compared with triaxial deformation at 0.00001/sec under the constraint of uniaxial strain. For granite and for limestone at moderate pressure, the stress-strain relation was nearly identical in the two tests; strain under these conditions was elastically recoverable. For the limestone at high pressure and for the tonalite at all pressures, volume decreased permanently. This permanent deformation, compared here for shock...
Topics: DTIC Archive, Brace, W F, MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF EARTH ATMOSPHERIC AND...
During the reporting period a stress-strain relationship was derived for the study of the interface phenomena when a high intensity stress wave impinges on a geologic boundary. The derived relationship was based on the ultimate density concept, i.e., the density of the material increases non- linearly with increasing stresses approaching a limiting value before a polymorphic phase transformation occurs. The derived stress-strain relationship was compared with high pressure data for three rock...
Topics: DTIC Archive, Amini, Ali, UTD INC NEWINGTON VA, *SOILS, *SEISMIC WAVES, *STRESS WAVES, THICKNESS,...
As a result of our studies, we conclude that liquid propellant is permanently altered by precursory electrolysis and that focusing outside the drop produces more decomposition. This is attributed to the combined effects of the plasma and shock wave generated during breakdown. It is shown that the NO formed in the air plasma also plays a part. There is little or no difference between the results for Q-switched and free running pulses at the same total energy. Heat treatment followed by varying...
Topics: DTIC Archive, Carleton, F B, IMPERIAL COLL OF SCIENCE AND TECHNOLOGYLONDON (UNITED KINGDOM), *SHOCK...
A workshop on shock waves was held at North Caroline State University, May 23-25, 1990. The workshop brought together mathematicians interested in the following areas related to shock waves: the theory of hyperbolic conservation laws, numerical methods for hyperbolic and parabolic systems of equations, the theory of travelling waves (viscous profiles) for parabolic systems, and applications.
Topics: DTIC Archive, Shearer, Michael, NORTH CAROLINA STATE UNIV AT RALEIGH, *SHOCK WAVES, PROFILES,...
Solar disturbances produce major effects on the corona, the solar wind, the interplanetary medium, and the Earth along with its magnetosphere. We have developed new techniques for studying plasma disturbances in the inner heliosphere by remotely sensing them. These techniques use data from the HELIOS spacecraft zodiacal light photometers, the ISEE-3 spacecraft kilometer radio- wave experiment, and a variety of other spacecraft and ground-based instruments. New in this study is our use of...
Topics: DTIC Archive, Jackson, Bernard V, CALIFORNIA UNIV SAN DIEGO LA JOLLA, *PLASMAS(PHYSICS), *RADIO...
6
6.0
audio
eye 6
favorite 0
comment 0
Topics: Radio Program, Geography, Former British colonies, Ozone depletion, Planetary science, G20 nations,...
7
7.0
audio
eye 7
favorite 0
comment 0
Topics: Radio Program, Geography, Former British colonies, Ozone depletion, Planetary science, G20 nations,...
The three dimensional shock wave turbulent boundary layer interaction generated by several shock generators defined solely by angles has been carried out at a Mach number of 3. Interactions with thin boundary layers were used to obtain overall characteristics, while interactions with thick boundary layers permitted detailed high resolution surveys. Investigations of the interactions were carried out by mean and high frequency surface pressure distribution measurements, surface flow...
Topics: DTIC Archive, Bogdonoff,Seymour M, PRINCETON UNIV NJ DEPT OF MECHANICAL AND AEROSPACE ENGINEERING,...
The design of aircraft for sustained operation at hypersonic speeds requires the understanding of aerodynamic heating generated through interfering flow fields. Such interactions not only determine the required level of vehicle thermal protection but also create severe gradients of temperature along skin panels. An extensive experimental program supporting the conceptual design of these vehicles was completed. Experimental results were generated on models illuminating the basic features of both...
Topics: DTIC Archive, Neumann, Richard D, AIR FORCE FLIGHT DYNAMICS LAB WRIGHT-PATTERSON AFB OH,...
Hydrocode simulations were conducted to analyze the non-linear response of 1100-O aluminum plates with semi-circular notches. Plates with constant notch depth and notch root radius were loaded (normal to the notch-tip plane) to the same shock stress while the notch spacing was varied. The resulting stress distributions were analyzed at specific locations between adjacent notches and then the maximum tensile stress developed was determined for different notch spacing. The results show that the...
Topics: DTIC Archive, ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH...
Using proxy data for the occurrence of those mass ejections from the solar corona which are directed earthward, we investigate the association between the post-1970 interplanetary magnetic clouds of Klein and Burlaga and coronal mass ejections. The evidence linking magnetic clouds following shocks with coronal mass ejections is striking; six of nine clouds observed at Earth were preceded an appropriate time earlier by meter-wave type II radio bursts indicative of coronal shock waves and coronal...
Topics: NASA Technical Reports Server (NTRS), INTERPLANETARY MAGNETIC FIELDS, MAGNETIC CLOUDS, STELLAR...
Two major episodes of heliospheric VLF emissions near 3 kHz have been observed by the Voyager spacecraft in 1983-1984 and 1992-1993. This higher-frequency component is apparently triggered by solar wind transients with sufficiently large spatial extents and energies to continue to propagate as shocks in the heliosheath. Entrainment of previously unshocked material and changed flow conditions in the heliosheath both tend to slow the shock propagation. The shock evolution is not self-similar....
Topics: NASA Technical Reports Server (NTRS), HELIOSPHERE, RADIO EMISSION, SOLAR WIND, SHOCK WAVES,...
Impact is an ubiquitous physical process in the solar system. It occurs on all solid bodies and operates over a spectrum of scales, influencing geologic processes ranging from accretion, the early evolution of planetary bodies, the petrogenetic and spatial relations of lunar samples, the surface characteristics and interpretation of spectral data of asteroidal bodies, to the nature of some meteorites. Understanding impact phenomena is therefore paramount in constraining and underpinning a large...
Topics: NASA Technical Reports Server (NTRS), DEPOSITION, EXPERIMENT DESIGN, GEOLOGY, GRAVITATIONAL...
A method for calculating unsteady flows in cascades is presented. The model, which is based on the linearized unsteady Euler equations, accounts for blade loading shock motion, wake motion, and blade geometry. The mean flow through the cascade is determined by solving the full nonlinear Euler equations. Assuming the unsteadiness in the flow is small, then the Euler equations are linearized about the mean flow to obtain a set of linear variable coefficient equations which describe the small...
Topics: NASA Technical Reports Server (NTRS), CASCADE FLOW, COMPUTATIONAL FLUID DYNAMICS, EULER EQUATIONS...
In the last two decades there have been extensive developments in computational unsteady transonic aerodynamics. Such developments are essential since the transonic regime plays an important role in the design of modern aircraft. Therefore, there has been a large effort to develop computational tools with which to accurately perform flutter analysis at transonic speeds. In the area of Computational Fluid Dynamics (CFD), unsteady transonic aerodynamics are characterized by the feature of...
Topics: NASA Technical Reports Server (NTRS), AEROELASTICITY, COMPUTATIONAL FLUID DYNAMICS, FLUTTER...
Two areas of research are briefly summarized. The first is concerned with calculating the conductivity of a slightly ionized gas. A method is proposed which involves an expansion of the Boltzmann collision operator (of the electron distribution function, involving the neutral gas-electron interactions) in powers of the electron-gas mass ratio. The second area of investigation focuses on the problem of a radio wave propagating through the interplanetary medium, taking account of the decreasing...
Topics: NASA Technical Reports Server (NTRS), ELECTRICAL RESISTIVITY, IONIZED GASES, MICROWAVES,...
