Saffman, P. G.Overview
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Most widely held works by
P. G Saffman
Vortex dynamics
by P. G Saffman
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Book
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27 editions published between 1992 and 2001 in English and Spanish and held by 522 WorldCat member libraries worldwide The discovery of coherent structures in turbulence has fostered the hope that the study of vortices will lead to models and an understanding of turbulent flow, thereby solving or at least making less mysterious one of the great unresolved problems of classical physics. Vortex dynamics is a natural paradigm for the field of chaotic motion and modern dynamical system theory. The emphasis in this monograph is on the classical theory of inviscid incompressible fluids containing finite regions of vorticity. The effects of viscosity, compressibility, inhomogeneity, and stratification are enormously important in many fields of application, from hypersonic flight to global environmental fluid mechanics. However, this volume focuses on those aspects of fluid motion that are primarily controlled by the vorticity and are such that the effects of the other fluid properties are secondary. This book will be of interest to students of fluid mechanics, turbulence, and vortex methods as well as to applied mathematicians and engineers
An application of the WienerHermite expansion to the diffusion of a passive scalar in a homogeneous turbulent flow
by P. G Saffman
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Book
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4 editions published between 1967 and 1968 in English and held by 22 WorldCat member libraries worldwide The report describes the application of a truncated WienerHermite expansion of the velocity and concentration fields to analyze (1) the diffusion and mixing of a passive scalar from a point source in a turbulent fluid, and (2) the spectrum and intensity decay of a homogeneous distribution in an approximately homogeneous flow. The problem has important practical applications in reentry physics and air and water pollution. The truncated WienerHermite expansion is treated as an approximation to the velocity field that must satisfy the NavierStokes equations; it is truncated at the first stage that gives nontrivial results. The mean concentration from a point source is shown to satisfy an integrodifferential equation with diffusive and wavelike properties. The effective diffusivity is determined in terms of Eulerian velocity coordinates. For the homogeneous case, the concentration spectrum equals the energy spectrum times the meansquare concentration divided by the meansquare velocity component. A modification of Batchelor's theory is combined with this equation to predict the decay rate
Research in Nonlinear Water Waves
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Book
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8 editions published between 1989 and 1991 in English and held by 8 WorldCat member libraries worldwide The major effort has been work on the calculation of wind drift effects on the properties of finite amplitude capillary gravity waves. The code is extended to the case when the wave is not too steep and the wind drift layer is thin compared with the height of the wave. Results have been obtained showing the effect of the wind drift layer on the properties of finite amplitude waves of permanent form. These are currently being validated to compare with the theory of Banner & Phillips which models the wind drift layer by a quasionedimensional sheet. The construction of a boundary integral type code is being evaluated which will enable the calculation of the effect of the wind drift layer on steep waves. A remarkable result is the stability of the waves when there is a wind drift layer. It appears that infinitesimal waves may be spontaneously unstable in the presence of a thin drift layer of sufficient strength. First results indicate that capillary gravity waves in a narrow band of around 2 cm wavelength are unstable for a wind drift layer corresponding to a wind speed of around 15 knots. This appears to be a complete new mechanism for the generation of waves by wind, since it is independent of the air motion once the wind drift layer is set up by viscous or turbulent stresses. (jhd)
The motion of a vortex filament with axial flow
by Donald W Moore
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Book
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2 editions published in 1972 in English and held by 3 WorldCat member libraries worldwide
Randon advection of a passive scalar
by James P Gleeson
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Book
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1 edition published in 1999 in English and held by 1 WorldCat member library worldwide
Equilibrium Shapes of a Pair of Equal Uniform Vortices
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Book
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1 edition published in 1980 in English and held by 1 WorldCat member library worldwide
Part I. Symmetry breaking of water waves : Part II. On the superharmonic instability of surface water waves
by Juan Antonio Zufiria
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Book
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1 edition published in 1987 in English and held by 1 WorldCat member library worldwide
On the motion of drops, bubbles and particles in fluids
by P. G Saffman
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Book
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1 edition published in 1956 in English and held by 1 WorldCat member library worldwide
Water Wave Instability Induced by a Drift Layer
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Book
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1 edition published in 1989 in English and held by 1 WorldCat member library worldwide A simple instability mechanism by which water waves can extract energy from a shear flow is isolated. A cubic equation is derived which provides the instability criteria and the growth rate. This mechanism is effective only if the surface drift velocity exceeds the minimum wave speed, which is approximately 23 cm/s in water, and only if the drift layer thickness exceeds a minimum value which is comparable with the unstable wavelength. In the situation of a sufficiently strong wind blowing over a flat calm, this mechanism is triggered early in the development stage, and appears to dominate the initial growth stages of centimeter waves. (JHD)
LiePoisson integrators in Hamiltonian fluid mechanics
by Barry James Ryan
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Book
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1 edition published in 1993 in English and held by 1 WorldCat member library worldwide
The motion of a disc at angle of attack in a rapidly rotating fluid
by David C Wilcox
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Book
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1 edition published in 1970 in English and held by 1 WorldCat member library worldwide
Steady GravityCapillary Waves on Deep Water. II. Numerical Results for Finite Amplitude
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Book
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1 edition published in 1979 in English and held by 1 WorldCat member library worldwide
Steady GravityCapillary Waves On Deep Water. I. Weakly Nonlinear Waves
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Book
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1 edition published in 1978 in English and held by 1 WorldCat member library worldwide
Stability of random nonlinear deep water waves with finite bandwidth spectra
by Irwin E Alber
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Book
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1 edition published in 1978 in English and held by 1 WorldCat member library worldwide
The rotation of a gravitating sphere in a monatomic gas. The drag of a body moving transversely in a confined stratified fluid
by Michael R Foster
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Book
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1 edition published in 1969 in English and held by 1 WorldCat member library worldwide
Point vortex models for modon dynamics
by Dana Hobson
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Book
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1 edition published in 1991 in English and held by 1 WorldCat member library worldwide
Structure of a Linear Array of Uniform Vortices
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Book
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1 edition published in 1979 in English and held by 1 WorldCat member library worldwide
Modulation of Radar Backscatter from the Ocean by a Variable Surface Current
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Book
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1 edition published in 1988 in English and held by 1 WorldCat member library worldwide Calculations of surface wave and radar cross section modulation induced by a spatially varying surface current have been compared with field measurements made with SAR (X and Lbands), real aperture radar (Xband), laser slope guage, and CCD video camera during the Joint Canada/U.S. Ocean Wave Investigation Project (JOWIP) which took place in August 1983. The comparison reveals that (i) many existing windrelaxation models underpredict the hydrodynamic effect of the current, (ii) simple Bragg scattering model underpredicts radar backscatter modulation for higher frequency radars (e.g., Xband) but appears acceptable at lower radar frequencies (e.g., Lband), (iii) the discrepancy between measurements and calculations at high radar frequency is reduced, but not eliminated, when the effects of long surface waves have been accounted for. Keywords include: Radar backscatter, Surface wave modulations, Wavecurrent interactions, Georgia strait experiment, and JOWIP. (RRH)
A model for the Von Kármán vortex street
by James Carl Schatzman
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Book
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1 edition published in 1981 in English and held by 1 WorldCat member library worldwide
Effects of Long Waves on the Generation of Waves by Wind
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1 edition published in 1997 in English and held by 1 WorldCat member library worldwide The program objective was a quantitative understanding of the properties of the short wind generated waves relevant to the interpretation of remote sensing radar images of the ocean. To that effect, the work has focused on the interaction between long and short waves in the presence of water and wind shear more
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Alternative Names
Saffman, P. G.
Saffman, Philip G.
Saffman, Philip Geoffrey.
Sèffmèn. F. Dž.
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