This work shows quantitatively the pronounced differences between the density equilibration of very compressible dense fluids in Earth's gravity and those in microgravity. The work was performed onsite at the NASA Glenn Research Center at Lewis Field and is complete. Full details are given in references 1 and 2. Liquid-vapor critical fluids (e.g., water) at their critical temperature and pressure, are very compressible. They collapse under their own weight in Earth's gravity, allowing only a...

Topics: NASA Technical Reports Server (NTRS), COMPRESSIBLE FLUIDS, EARTH GRAVITATION, HYDRODYNAMICS,...

A numerical harbor resonance model of the Los Angeles/Long Beach Harbor Complex was used to study harbor oscillations in the 60- to 400-sec period range. Four finite element grids were digitized representing existing conditions and two Phase 2 and Phase 1 layouts from the 2020 Plan. The hybrid finite element numerical model HARBD, which includes terms for bottom friction and boundary absorption, was used in this study. Mean boundary amplification response factors were obtained for 30 basins...

Topics: DTIC Archive, Sargent, Francis E, COASTAL ENGINEERING RESEARCH CENTER VICKSBURG MS, *HARBOR MODELS,...

Despite the numerous natural and technological occurrences of transport processes due to complex driving forces little information about them is available. Under this grant we have begun to study several different coupled convection problems. Study topics include: Combined thermal and hydrodynamic instability; Effects of stabilizing temperature gradients on confined natural convection flows; Convection induced by combined horizontal temperature and concentration gradients; and Waste heat...

Topics: DTIC Archive, Ostrach, Simon, CASE INST OF TECH CLEVELAND OH, *HEAT TRANSFER, *FLUID FLOW,...

The results of the investigation in the area of the hydrofoil theory are systematized in this monograph. A great deal of attention is given to the mechanical-mathematical aspects of the hydrofoil theory and to the development of the effective methods for solving the basic equations in the hydrofoil theory. This book considers the theory of steady motion of a wing with an arbitrary profile in a plane-parallel flow; the linear theory of thin hydrofoils in the two-dimensional and three-dimensional...

Topics: DTIC Archive, Panchenkov, A N, NAVAL INTELLIGENCE SUPPORT CENTER WASHINGTON DC TRANSLATION DIV,...

The effects of velocity on the corrosion of galvanic couples (70/30 Cu-Ni/plain carbon steel and K-Monel/plain carbon steel) in synthetic seawater electrolyte were studied. A unique experimental apparatus was designed and built, employing a foil-shaped specimen holder rotating in a tank, and the hydrodynamic flow conditions within the test system were carefully characterized. Galvanic current measurements were taken at various velocities and corrosion product formation and dissolution patterns...

Topics: DTIC Archive, Storm,Gary Alan, NAVAL POSTGRADUATE SCHOOL MONTEREY CALIF, *SEA WATER CORROSION,...

A meeting was held at St. Johns College, Oxford from Monday 27th to Thursday 30th of September 1993 to bring together a group of physicists working on computational modelling of plasma spectroscopy. The group came from the UK, France, Israel and the USA. The meeting was organized by myself, Dr. Steven Rose of RAL and Dr. R. W. Lee of LLNL. It was funded by the US European Office of Aerospace Research and Development and by LLNL. The meeting grew out of a wish by a group of core participants to...

Topics: DTIC Archive, EUROPEAN OFFICE OF AEROSPACE RESEARCH AND DEVELOPMENT FPO NEW YORK 09510,...

We present results of experiments on very-high Mach number ( 100) shocks and very-high Mach number and Reynolds number ( 100, 106) turbulence. Such high Mach number hydrodynamics are initiated with a powerful laser pulse driver. We show that shocks created with a laser driver follow the Taylor-Sedov self-similar solution and scale via the Sachs scaling law just like shocks created by more traditional methods. In one experiment we examined laser- produced-shock solid-surface interactions and...

Topics: DTIC Archive, Grun, Jacob, NAVAL RESEARCH LAB WASHINGTON DC, *SHOCK WAVES, *PULSED LASERS, *MACH...

Simulation of water flow from the rainbird nozzles has been accomplished using the Smoothed Particle Hydrodynamics (SPH). The advantage of using SPH is that no meshing is required, thus the grid quality is no longer an issue and accuracy can be improved.

Topics: NASA Technical Reports Server (NTRS), WATER FLOW, HYDRODYNAMICS, PARTICLE MOTION, SIMULATION,...

A series of progressively finer grid systems to calculate the single jet in cross-flow experimentally measured were employed. The experimental measurements provide a collection of velocities, turbulence intensities, and jet concentration profiles with measurements of the inlet field. The use of a series of progressively finer grid systems allows a differentiation between numerical errors and the hydrodynamic modeling assumptions embodied in the 3D combustor code.

Topics: NASA Technical Reports Server (NTRS), AIR JETS, COMBUSTION CHAMBERS, COORDINATES, CROSS FLOW,...

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40

Feb 26, 2010
02/10

by
Willis, Shirley

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Topics: Archimedes' principle, Floating bodies, Buoyant ascent (Hydrodynamics), Archimedes' principle,...

The purpose of this thesis is to determine the feasibility of lengthening the current DDG-51 ARLEIGH BURKE class destroyers and the resulting effects on the hydrostatics and hydrodynamics. A modified repeat of a current, proven ship design would offer a more cost-effective solution for the acquisition of ships to reach the U.S. Navy goal of a 313-ship fleet in the 30-year shipbuilding plan. An analysis is performed to determine a proposed length that would be added to the ship at the parallel...

Topics: Hydrostatics, Hydrodynamics, Mechanical engineering

A general physics based hydrodynamic flow model is developed that predicts the three-dimensional six degrees of freedom free fall time history of a circular cylinder through the water column to impact with an unspecified bottom. Accurate vertical impact velocity and impact angle parameters are required inputs to subsequent portions of any Impact Mine Burial Model. The model vertical impact velocity and impact angle are compared with experimental data, vertical impact velocities and impact angle...

Topics: Submarine mines, Hydrodynamics, Mine impact burial, IMPACT28, Bottom mine, Mine countermeasures,...

CMCAM, an extendable lattice-gas simulation program for the Thinking Machines Corporation CM-5 supercomputer is described. CMCAM manipulates the vector processing accelerator units present on each CM-5 processing node using GCC/DPEAC, a macro package for issuing assembler instructions from a C program. The system is able to run several lattice gas rules and extract time and space averaged data for further processing. X-Window graphics are built into the code for remote display of 2-d...

Topics: DTIC Archive, Seeley, G P, RADEX INC BEDFORD MA, *SUPERCOMPUTERS, *HYDRODYNAMICS, COMPUTER...

This report presents the mechanics of performing a verification and validation analysis for practical problems, focusing mainly on the estimation of uncertainty in the numerical prediction due to the use of finite grid sizes. A detailed example is presented along with discussions regarding many of the practical issues involved in performing a rigorous verification and validation analysis. The particular approach outlined in this report is mainly based on theoretical work performed at the Iowa...

Topics: DTIC Archive, Ebert, Michael P, NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD...

Professor R. D. Richtmyer has described a finite difference method for the computation of hydrodynamic flows which contain a shock. This method uses the Eulerian form of the hydrodynamic equations, is explicit, is of second order accuracy, and is based on shock fitting rather than the introduction of artificial viscosity. This paper describes the result of numerical computations using a modification of this finite difference method. The method is applied to a one-dimensional problem for which a...

Topics: DTIC Archive, Gary, John, NEW YORK UNIV NY COURANT INST OF MATHEMATICAL SCIENCES, *HYDRODYNAMICS,...

Wind waves and swell dominate the hydrodynamic and sediment transport processes on many continental shelves and beaches, affect underwater acoustics, and play an important role in remote sensing applications. Wave prediction in coastal environments is a challenging task because waves are affected by many processes, including scattering by seafloor topography, strong nonlinear interactions, wave breaking, and friction in the bottom boundary layer. Several of these processes are poorly understood...

Topics: DTIC Archive, NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF OCEANOGRAPHY, *BEACHES, *SURFACE WAVES,...

A hydrodynamic model describing water movement and tidal elevation is formulated, computed, and used to provide basic data about water quality in natural systems. The hydrodynamic model is based on two-dimensional, unsteady flow equations. The water mass is considered to be reasonably mixed such that integration (averaging) in the depth direction is a valid restriction. Convective acceleration, the Coriolis force, wind and bottom interactions are included as contributing terms in the momentum...

Topics: NASA Technical Reports Server (NTRS), ALABAMA, RESOURCES MANAGEMENT, WATER RESOURCES, FLOW...

The axial pump is considered in terms of the total turbopump assembly. Stage hydrodynamic design, pump rotor assembly, pump materials for liquid hydrogen applications, and safety factors as utilized in state of the art pumps are among the topics discussed. Axial pump applications are included.

Topics: NASA Technical Reports Server (NTRS), AXIAL FLOW PUMPS, ENGINE DESIGN, LIQUID PROPELLANT ROCKET...

Hydrodynamic simulations of exploding copper foils, which are irradiated on one side by 1.06 micron laser light, indicated that peak axial electron number density is more easily controlled with split-foil target design. Results from a series of simulations with solid copper foils that range in width from 500A to 1500A show that while peak electron temperature and time of burnthrough can be varied, evolved electron number densities are approximately bounded from above by 3 X 10 to the 20th power...

Topics: DTIC Archive, Dahlburg,Jill P, NAVAL RESEARCH LAB WASHINGTON DC, *PLASMAS(PHYSICS), *LASERS, *X...

This paper presents a method for estimating the forces and moments on the six axes of an Unmanned Underwater Vehicle (UUV) operating in close proximity to a host vesseL Forces and moments encountered by the vehicle in the host vessel launchway, near the vessel and clear of the launchway, and far away from the host vessel, are modeled from experimental and theoretical sources. A quasi - steady approach to the vehicle launch dynamics allows coupling of experimental data, potential flow theory,...

Topics: DTIC Archive, Riggle, Jess E., MASSACHUSETTS INST OF TECH CAMBRIDGE, *UNDERWATER VEHICLES,...

The hydrodynamic pressure distribution has been measured on the SQS-26 sonar dome of a CGN-38 Class ship model. Experiments were conducted primarily in head regular wave conditions; however, some data was collected in irregular head waves and in regular and irregular waves at 45 degress off the port bow. Regular wave responses are presented in the form of response amplitude operators and the irregular wave results are presented as significant values of response. (Author)

Topics: DTIC Archive, Motter,Lewis E, DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER BETHESDA MD...

This report details the progress achieved by the Radiation Hydrodynamics Branch in X-Ray Laser experiments and modeling during FY91. Some of the experimental work discussed was carried out at Sandia National Laboratories in a cooperative program with NRL. It is divided into sections whose authors are separately identified. Topics presented in detail include the first demonstration of a soft x-ray inversion by resonant photopumping, detailed analysis of other photopumped x-ray laser scheme,...

Topics: DTIC Archive, NAVAL RESEARCH LAB WASHINGTON DC, *HYDRODYNAMICS, *X RAY LASERS, RADIATION,...

A mathematical analysis is developed for the hydrodynamic problem of a two-dimensional planing surface which is heaving sinusoidally. From the assumptions of small angle of attack and small amplitudes of motion, it is possible to formulate a linear problem. Gravity is neglected. A condition is developed for predicting instability of the steady forward motion.

Topics: DTIC Archive, Ogilvie, T F, MICHIGAN UNIV ANN ARBOR DEPT OF NAVAL ARCHITECTURE AND MARINE...

A model for the propeller-singing phenomenon considered as a self- excited oscillation is presented to interpret the finding of a recent experimental work; viz., that, although the singing frequency roughly obeys the well-known Strouhal relation, once the strong singing state has been established, the frequency is kept constant through a fairly wide range of flow velocity, and consequently the frequencyversus-velocity diagram exhibits step and jump characteristics. The model presented is a...

Topics: DTIC Archive, Shioiri, Jumpei, STEVENS INST OF TECH HOBOKEN NJ DAVIDSON LAB, *MARINE PROPELLERS,...

Topics: DTIC Archive, OFFICE OF SCIENTIFIC RESEARCH AND DEVELOPMENT WASHINGTON DC, *CONTROL SYSTEMS,...

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2.0

Jun 20, 2020
06/20

by
Murray, Julie, 1969-

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1 online resource (24 pages) :

Topics: Floating bodies -- Juvenile literature, Hydrostatics -- Juvenile literature, Buoyant ascent...

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0.0

Aug 9, 2020
08/20

by
Soloviev, Alexander

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xiv, 572 p. : 25 cm

Topics: Ocean-atmosphere interaction, Hydrodynamics, Chemical oceanography, Ocean waves, Ocean temperature

Topics: DTIC Archive, BRIDGES, W B, CALIFORNIA UNIV BERKELEY ELECTRONICS RESEARCH LAB, *FLUID FLOW, *DRIFT,...

An attempt is made to develop a simple yet accurate gas breakdown model which can be easily coupled to the hydrodynamic equations governing fluid flow in laser-target interactions. The accuracy of three relatively simple models is investigated. Each is compared with the more accurate and complex quantum kinetic model. A gas consisting of a single monatomic species is assumed and attention is restricted to the early portion of the electron cascade. A temperature model is found to agree...

Topics: DTIC Archive, Kloc,David A, AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OHIO SCHOOL OF ENGINEERING,...

A hydrodynamic air bearing with a compliment surface is used in the gas generator of an upgraded automotive gas turbine engine. In the prototype design, the compliant surface is a thin foil spot welded at one end to the bearing cartridge. During operation, the foil failed along the line of spot welds which acted as a series of stress concentrators. Because of its higher degree of geometric uniformity, electron beam welding of the foil was selected as an alternative to spot welding. Room...

Topics: NASA Technical Reports Server (NTRS), BENDING FATIGUE, ELECTRON BEAM WELDING, FATIGUE LIFE, FOIL...

The primary thrust of this study was toward a more complete understanding of general aspects of acoustic cavitation. The effect of long- chain polymer additives on the cavitation threshold was investigated to determine if they reduced the acoustic cavitation threshold in a similar manner to the observed reduction in the cavitation index in hydrodynamic cavitation. Measurements were made of the acoustic cavitation threshold as a function of polymer concentration for additives such as guar gum...

Topics: DTIC Archive, Crum, Lawrence A, MISSISSIPPI UNIV UNIVERSITY DEPT OF PHYSICS AND ASTRONOMY,...

Wave generated oscillatory currents along the ocean floor provide one of the more important forces participating in the erosion, transportation, and deposition of marine sediments. These currents are especially active in the eulitorial zone which ranges from the high tide level to a depth of 150 feet. Significant currents in the sublittoral zone, which continues from the lower border of the eulittoral zone to a depth of 600 feet or the edge of the continental shelf, are generated only by...

Topics: DTIC Archive, Hunt,Lee M, NATIONAL ACADEMY OF SCIENCES-NATIONAL RESEARCH COUNCIL WASHINGTON D C...

A theoretical model which explains basic properties of radar imaging of underwater bottom topography in tidal channels is presented. The surface roughness modulation is described by weak hydrodynamic interaction theory in the relaxation time approximation. In contrast to previous theories on short wave modulation by long ocean waves, a different approximation is used to describe short wave modulation by tidal flow over underwater bottom topography. The modulation depth is proportional to the...

Topics: NASA Technical Reports Server (NTRS), BRAGG CURVE, HYDRODYNAMICS, MODULATION, OCEAN BOTTOM, OCEAN...

0
0.0

Jul 20, 2020
07/20

by
Mara, Wil

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pages cm

Topics: Textile fabrics -- Technological innovations -- Juvenile literature, Bathing suits -- Design --...

The use of similarity flows is discussed in certain hydrodynamic impact problems, as a basis for approximate analytical solutions. After a qualitative discussion of various ways in which such solutions may be obtained, a single derivation is obtained of a class of oneparameter similarity flows for problems in 1, 2 and 3 dimensions, which includes substantially all those used previously, and allows the superposition of constant uniform motions. The perturbation equations which relate the...

Topics: DTIC Archive, GENERAL DYNAMICS SAN DIEGO CA GENERAL ATOMIC DIV, *HYDRODYNAMICS, *PARTIAL...

Topics: DTIC Archive, YANG, KWANG-TZU, NOTRE DAME UNIV IN DEPT OF ENGINEERING SCIENCE, *LAMINAR BOUNDARY...

The report contains information on the design, installation, and interconnections of equipment used in the freerunning model test program. Emphasis is placed on describing those portions of the system designed and assembled by CAL for these specific tests and for which information is not elsewhere available. Where possible, reference is made to prior publications for descriptions of equipment which was supplied with the model (e. g., the propeller and blade actuator servomechanisms) or which...

Topics: DTIC Archive, CORNELL AERONAUTICAL LAB INC BUFFALO NY, *HYDRODYNAMICS, *MARINE PROPELLERS,...

8
8.0

Oct 18, 2018
10/18

by
Cobb, Vicki

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1 online resource (48 pages) :

Topics: Hydrodynamics -- Juvenile literature, Water -- Experiments, Experiments, JUVENILE NONFICTION --...

The researchers formulated a theory to describe and calculate the dynamical dielectric response of classical interacting molecular liquids in terms of their corresponding static response functions. There are two basic ideas in this approach. One idea is to use a local effective field to tale into account the long range coherent effects of the molecular interactions. These local fields are derived from the static structural properties of the liquid. The other idea to calculate the self-part of...

Topics: DTIC Archive, Vignale, Giovanni, MISSOURI UNIV-COLUMBIA DEPT OF PHYSICS, *DIELECTRICS, *HYDROSTATIC...

Over the past two decades, several two-phase-flow interior ballistic codes have been developed. Generally, they have treated ignition-induced pressure waves as a hydrodynamic problem which arises from the ignition stimulus, the propellant geometry, the path of flame-spreading in the propellant bed, and the interaction of charge and chamber. Ignition and combustion have been treated as a simple process, with convectively-driven inert heating of the propellant until a surface-temperature...

Topics: DTIC Archive, Horst, Albert W, ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD, *INTERIOR...

This study investigated the effectiveness of foam linings in mitigating shock waves in tunnels. A polyurethane foam liner of varying density, crush strength and thickness was modeled inside a 1 meter radius tunnel and an explosion of 1.25 kg of plastic explosive was simulated. Using CTH, an Eulerian- Lagrangian hydrodynamics code from Sandia National Laboratories, the overpressures were computed and compared graphically to determine the effect of varying each foam parameter. The walls of the...

Topics: DTIC Archive, Fondaw, Grant W, AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH, *SHOCK WAVES,...

This study was undertaken to develop a user friendly computer model to simulate heavily loaded lubricated circular and elliptic contacts, i.e., point contacts. In order to achieve this objective, a numerical model for newtonian thermal elastohydrodynamic (EHD) lubrication of rolling/sliding contacts was developed. The model simultaneously solves the two-dimensional reynolds, elasticity, and three-dimensional energy equations to obtain pressure, film thickness, and temperature distribution...

Topics: DTIC Archive, Sadeghi, Farshid, UNIVERSAL ENERGY SYSTEMS INC DAYTON OH, *ELASTIC PROPERTIES,...

The galaxy merging is investigated with hydrodynamical processes taken into account. For this purpose, the 3D calculations are performed by the use of a smoothed particle hydrodynamics (SPH) scheme combined with an N-body scheme. In these calculations, we find a new merging criterion and the dependence of the central phase space density of merger remnants upon the gas fraction in progenitors. It is concluded that ellipticals can be formed just by merging of fairly gas-rich primordial galaxies,...

Topics: NASA Technical Reports Server (NTRS), ASTRONOMICAL MODELS, ELLIPTICAL GALAXIES, GALACTIC EVOLUTION,...

Internal fluid flows are subject not only to self-sustained oscillations of the purely hydrodynamic type but also to the coupling of the instability with the acoustic mode of the surrounding cavity. This situation is common to turbomachinery, since flow instabilities are confined within a flow path where the acoustic wavelength is typically smaller than the dimensions of the cavity and flow speeds are low enough to allow resonances. When acoustic coupling occurs, the fluctuations can become so...

Topics: NASA Technical Reports Server (NTRS), ACOUSTIC COUPLING, ACOUSTICS, CAVITIES, CAVITY FLOW, DUCTS,...

This report gives a summary of the main electrochemcial features of pitting corrosion of iron, aluminum, magnesium, titanium, and stainless steel in halide solutions. Ohmic and mass transport limited corrosion regions and effect of hydrodynamic flow are described. Barrier films of metal halide salt are formed on the metal surface for these metals in the mass transport limited region. The electrical properties of these salt films were determined. A mechanism is proposed for the protection from...

Topics: DTIC Archive, Beck, Theodore R, ELECTROCHEMICAL TECHNOLOGY CORP SEATTLEWA, *METALS, *CORROSION,...

Dynamics of the circulation in the Sea of Marmara are investigated with a time dependent, three dimensional numerical model. The empirically inferred hydrologic regimes of the sea and connective straits are discussed. A baroclinic model based on the primitive equations is solved by direct integration of an initial value problem. The circulation in the sea is driven by surface forces that simulated wind stress and horizontal pressure gradient forces related to internal stratification. The...

Topics: DTIC Archive, Yuce,Huseyin, NAVAL POSTGRADUATE SCHOOL MONTEREY CALIF, *OCEAN CURRENTS, *OCEAN...

To obtain data on hydrodynamic slamming on the bottom of a large sonar dome of a DL-2 destroyer, a 20-ft model of the ship was tested in the Harold E. Saunders Maneuvering and Seakeeping Facility of the Naval Ship Research and Development Center. Both the probability of occurrence of slamming and the magnitude of the associated pressures wree investigated. The tests were conducted on a model of the DL-2 fitted with a sonar dome of the SQS 26 type.

Topics: DTIC Archive, Wahab,R, DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER BETHESDA MD DEPT...

A symmetric 3 mass rotor supported on hydrodynamic bearings is described. An approximate method of representing finite bearings is used to calculate bearing forces. As the method sums forces from a number of independent circular lobes lemon 3 and 4 lobe bearings are taken into account. The calculations are based on an axial groove bearing. Linear analysis precedes nonlinear simulation of some unstable conditions. The demonstration of small limit cycles suggests that necessarily flexible rotors...

Topics: NASA Technical Reports Server (NTRS), BEARING, FLEXIBILITY, HYDRODYNAMICS, LOADS (FORCES), SHAFTS...

This is a follow-on to the TOWARD experiment which was executed in 1984-1986 to provide experimental verification of the mechanisms responsible for Synthetic Aperture Radar (SAR) imaging of the ocean surface. The TOWARD experiment provided a data set that is adequate for resolving the most important issues related to SAR imaging of surface waves at L-Band. The mechanisms involved in SAR imaging at X-Band are far less understood (C-Band is in near proximity of X-Band). The SAXON experiment,...

Topics: DTIC Archive, Shemdin, O H, OCEAN RESEARCH AND ENGINEERING PASADENA CA, *SYNTHETIC APERTURE RADAR,...

This study describes the development of a vectorized, multiprocessing global spectral model (GSM) with enhanced physical parameterizations. The starting point was the Phillips Laboratory GSM, in its GL90 version, containing an enhanced suite of physical parameterizations. The latitude tasking scheme for multiprocessing the loop over latitude in the calculation of the spectral tendencies and adjusted model variables was implemented, using the general truncation version of the hydrodynamics code....

Topics: DTIC Archive, Nehrkorn, Thomas, ATMOSPHERIC AND ENVIRONMENTAL RESEARCH INC CAMBRIDGE MA, *WEATHER...