A simplified algorithm is described for the numerical solution of the Navier--Stokes equations. Because of its simple construction, the algorithm serves as a good introduction to numerical fluid dynamics as well as a basis for developing many kinds of new solution methods. To illustrate the flexibility of this ...
Energy Citations Database
In this work, the numerical solution to a few of the electrostatic problems is dealt with which have occured within the framework of the heavy ion accelerator project VICKSI. By means of these selected examples, the versatile applicability of the numerical method is to be demonstrated, and simultaneously ...
Solutions of the equation describing proton acceleration in the electric field of the Earth's geomagnetic tail often require lengthy numerical calculations and parametric exploration can be difficult. Here, considerations are presented of a scaling nature...
National Technical Information Service (NTIS)
The compressible Rayleigh-Taylor instability of a supersonic accelerated contact discontinuity between two gases is studied by numerically solving the two-dimensional Euler equations. The computed solutions exhibit a complicated set of nonlinear waves com...
A numerical analysis is made of the invescid flow produced by a cylinder which accelerates from a state of rest to a constant, subsonic speed in a gas at rest. All features of the numerical solution are explained on physical grounds. Consequently, ways ar...
The physics and numerical aspects of the development of the computer code QUARTZ are given. This code includes the (1) use of a finite element code to obtain solutions of Poisson's equation in an asymmetric, three-dimensional volume; (2) inclusion of spac...
We study the validity of the Born-Oppenheimer approximation in chaotic dynamics. Using numerical solutions of autonomous Fermi accelerators, we show that the general adiabatic conditions can be interpreted as the narrowness of the chaotic region in phase space.
NASA Astrophysics Data System (ADS)
An analytical solution of the two body problem perturbed by a constant tangential acceleration is derived with the aid of perturbation theory. The solution, which is valid for circular and elliptic orbits with generic eccentricity, describes the instantaneous time variation of all orbital elements. A comparison with high-accuracy ...
On the basis of the classic formula of the concentration Rayleigh number and the Kedem-Katchalsky equation for diffusive membrane transport, we derived the equations of sixteenth order which show the dependence of the thicknesses of the concentration boundary layers on the difference of the solution concentrations, the concentration Rayleigh number, the ...
PubMed
On the basis of the classic formula of the concentration Rayleigh number and the Kedem�Katchalsky equation for diffusive membrane transport, we derived the equations of sixteenth order which show the dependence of the thicknesses of the concentration boundary layers on the difference of the solution concentrations, the concentration Rayleigh number, the ...
PubMed Central
... Title : NUMERICAL SOLUTION OF FLOOD PREDICTION AND RIVER ... Descriptors : *FLOODS, HYDROLOGY, NUMERICAL METHODS AND ...
DTIC Science & Technology
... NUMERICAL SOLUTIONS OF PARABOLIC PDES ON MIMD MULTIPROCESSORS ... NUMERICAL SOLUTIONS OF PARABOLIC PDES ...
A class of Projected Discrete-Ordinates (PDO) methods is described for obtaining iterative solutions of discrete-ordinates problems with convergence rates comparable to those observed using Diffusion Synthetic Acceleration (DSA). The spatially discretized PDO solutions are generally not equal to the DSA solutions, ...
DOE Information Bridge
... SOLUTION TO THE FLOW OF A GASSOLID SUSPENSION THROUGH A ... A method of numerical solution of the basic gas dynamic equations ...
... The need for numerical methods; Approximate solution of the Dirichlet problem; Approximate solution of the Cauchy problem; Approximate solution ...
Solutions of the equation describing proton acceleration in the electric field of the Earth's geomagnetic tail often require lengthy numerical calculations and parametric exploration can be difficult. Here, considerations are presented of a scaling nature and shown that these considerations may be used to extend, correlate, ...
In this paper, the generalized Oldroyd-B with fractional calculus approach is used. An exact solution in terms of Fox-H function for flow past an accelerated horizontal plate in a rotating fluid is obtained by using discrete Laplace transform method. A comparison among the influence of various parameters in the Oldroyd-B model and the angular velocity of ...
... PARTIAL DIFFERENTIAL EQUATIONS, NUMERICAL ANALYSIS), (*NUMERICAL ANALYSIS, FOURIER ANALYSIS), (*NUMERICAL ANALYSIS ...
The Waterways Experiment Station one-dimensional (1D) finite difference ground motion calculation code was used to investigate the influences of grid size and acceleration convergence criteria on cutoff-frequency phenomena in the numerical solution of an ...
This study investigates two methods of increasing the rate of convergence of the two dimensional five point implicit finite difference representation of the diffusion equation of transient heat transfer. The two methods are adapted Wegstein and successive...
Results of HEMP code calculations of simple problems are compared with exact results to determine the accuracy with which this numerical technique solves initial-boundary value problems. More complicated problems of metal liners accelerated by explosives ...
... in the improved low-aspect-ratio approximation of ... A general method of numerical solution is derived for ... Numerical solutions are carried out for the ...
... Title : Numerical Solution of a Singular Integral Equation ... and physics, and their numerical solutions can be ... for a sequential probability ratio test. ...
In this paper we describe in full details a new family of recently found exact solutions of relativistic, perfect fluid dynamics. With an ansatz that generalizes the well-known Hwa-Bjorken solution we obtain a wide class of new exact, explicit, and simple solutions, which have a remarkable advantage as compared to presently known exact ...
The compressible Rayleigh--Taylor instability of a supersonic accelerated contact discontinuity between two gases is studied by numerically solving the two-dimensional Euler equations. The computed solutions exhibit a complicated set of nonlinear waves comprised of spike and bubble bow shocks, terminal shocks within the spike and ...
The acceleration of protons through the interaction of a circularly polarized ultrahigh intensity laser wave incident on an overdense plasma is studied using an Eulerian Vlasov code for the numerical solution of the one-dimensional (1D) relativistic Vlasov-Maxwell set of equations. The high power laser radiation is pushing the ...
... A feed-back extension procedure is developed for the numerical solution ... is the solution of ... Error Analy- is of Finite Element Solutions for Onte ...
The synchrotron oscillations during electron injection and acceleration to energies of approximately 1 to 2 Bev are analyzed. The non-linear differential equations describing the oscillations are set up, and the method of solution is discussed. An exact solution of the equations is not pcssible analytically, but ...
A popular strategy for the numerical solution to contact problems is based on Finite Elements with the contact constraints enforced by a penalty formulation. The resulting linearized system, however, can prove severely ill-conditioned, with the iterative solution to large 3D problems requiring expensive ILU-type preconditioners to ...
. When subjected to rapid acceleration, a metal plate that is not perfectly flat displays a type of Rayleigh-Taylor instability, which is affected by shear strength. We investigate the initial stage of this instability assuming that the deviation from flatness is small and the pressure producing the acceleration is moderate. Under these assumptions, the ...
E-print Network
This study deals with boundary layer flow along the entire length of a stationary semi-infinite cylinder under a steady, accelerated free-stream. Considering flow at reduced dimensions, the no-slip boundary condition is replaced with a Navier boundary condition. Asymptotic series solutions are obtained for the shear stress coefficient in terms of the ...
... warfare, joint planning, national and international ... Numerical Studies for the RAM Accelerator. ... Author : NAVAL RESEARCH LAB WASHINGTON DC ...
... in the Spiral Line Induction Accelerator ... Numerical Modelling of Intense Electron Beam Transport in the Spiral Line Induction Accelerator ...
A comprehensive study of the nonlinear dynamics of composite beams is presented. The study consists of static and dynamic solutions with and without active elements. The static solution provides the initial conditions for the dynamic analysis. The dynamic problems considered include the analyses of clamped (hingeless) and articulated (hinged) ...
The self-similar solutions are obtained for isothermal expansions of neutral plasmas into a vacuum. The classic solution given by Mora [Phys. Fluids 22, 12 (1979)] corresponds to a special case of our solution. Some special solutions have been pointed out by Gurevich et al. [Phys. Rev. Lett. 42, 769 (1979)] and ...
We present a new class of synthetic acceleration methods which can be applied to transport calculations regardless of geometry, discretization scheme, or mesh shape. Unlike other synthetic acceleration methods which base their acceleration on P1 equations, these methods use acceleration equations obtained by ...
A new class of synthetic acceleration methods, which can be applied to transport calculations regardless of geometry, discretization scheme, or mesh shape, is presented. Unlike other synthetic acceleration methods that base their acceleration on P/sub l/ equations, these methods use acceleration equations obtained ...
In many future collider and FEL designs intense, short bunches are accelerated in a linear accelerator. For example, in parts of the Linac Coherent Light Source (LCLS) a bunch with a peak current of 3.4 kA and an rms length of 30 microns will be accelerated in the SLAC linac. In such machines, in order to predict the beam quality at ...
... oblique detonations in the ram accelerator: Can the concept of using a stable, oblique detonation actually be viable for ram accelerators? ...
... Title : THE NUMERICAL SOLUTION OF THE HEAT CONDUCTION EQUATION OCCURRING IN THE THEORY OF THERMAL EXPLOSIONS. ...
... Accession Number : AD0267021. Title : ON THE NUMERICAL SOLUTION OF THE SECULAR EQUATION. Corporate Author ...
... solutions of transient, coupled thermoelasticity problems ... problem of transient response of a ... PROPERTIES, NUMERICAL ANALYSIS), NONLINEAR ...
Numerical techniques and solutions for compressible and incompressible laminar separated flows using
NASA Technical Reports Server (NTRS)
An effort is made to develop a satisfactory numerical method for the calculation of steady solutions
... Accession Number : ADD302456. Title : NUMERICAL SOLUTIONS FOR ACOUSTIC RAYLEIGH WAVE PROBLEMS IN ANISOTROPIC AND ...
... Title : NUMERICAL SOLUTION OF THE EQUATION GOVERNING NUCLEAR MAGNETIC SPIN LATTICE RELAXATION IN A PARAMAGNETIC ...
... Title : NUMERICAL SOLUTION OF HYPERBOLIC EQUATIONS AND SYSTEMS BY A METHOD OF THE RUNGE-KUTTA TYPE. II,. ...
... Title : NUMERICAL SOLUTION OF FUNCTIONAL EQUATIONS BY MEAMS OF LAPLACE TRANSFORM-4: NONLINEAR EQUATIONS. ...
... The ultimate aim is to carry out numerically the solution of a flood problem ... floods at the junction of the Ohio and the Mississippi, and ...
... Accession Number : AD0691037. Title : NUMERICAL SOLUTION OF DYNAMICAL OPTIMIZATION PROBLEMS,. Corporate ...
... Title : NUMERICAL SOLUTION OF A SYSTEM OF DIFFERENTIAL EQUATIONS APPLICATION OF THE METHOD TO THE CALCULATION OF A ...
... AD0621274. Title : AN ERROR ANALYSIS OF NUMERICAL SOLUTIONS OF THE TRANSIENT HEAT CONDUCTION EQUATION. ...
... Title : A NUMERICAL SOLUTION TO THE THERMAL-ELASTOHYDRODY NAMIC LUBRICATION OF ROLLING AND SLIDING CYLINDERS,. ...
... Title : A NUMERICAL SOLUTION OF THE ELASTO-HYDRODYNAMIC FILM THICKNESS IN AN ELLIPTICAL CONTACT. ...
... Title : A METHOD FOR THE RAPID NUMERICAL SOLUTION OF THE HEAT CONDUCTION EQUATION FOR COMPOSITE SLABS. ...
A computer program has been developed which uses a technique of synthetic acceleration by diffusion by analytical schemes. Both in the diffusion equation as in that of transport, analytical schemes were used which allowed a substantial time saving in the ...
We present the results of Bragg spectroscopy performed on an accelerating Bose-Einstein condensate. The Bose-Einstein condensate undergoes circular micromotion in a magnetic time-averaged orbiting potential trap and the effect of this motion on the Bragg spectrum is analyzed. A simple frequency modulation model is used to interpret the observed complex structure, and ...
In this paper, a two-loop implicit sparse matrix numerical integration (TLISMNI) procedure for the solution of constrained rigid and flexible multibody system differential and algebraic equations is proposed. The proposed method ensures that the kinematic constraint equations are satisfied at the position, velocity and acceleration ...
The nonideal characteristics of the electron beam have largely determined the performance of all free-electron laser (FEL) oscillators that have operated up to the present time. A realistic quantitative theoretical assessment of FEL oscillator performance must therefore include a viable representation of the electron beam's characteristics, as well as the properties of the wiggler magnet ...
Page 1. Direct Numerical Solution Of The Boltzmann Equation Felix Tcheremissine ... NUMERICAL METHOD Consider the Boltzmann equation ...
... Title : A Feedback Extension to the Numerical Solution of Nonlinear ... Abstract : A feed-back extension procedure is developed for the numerical ...
A semi-analytical mathematical model is developed to study the transient liquid sloshing characteristics in half-full horizontal cylindrical containers of elliptical cross section subjected to arbitrary lateral external acceleration. The problem solution is achieved by employing the linear potential theory in conjunction with conformal mapping, resulting ...
A general theory of the transverse instability of coasting beams in circular accelerators produced by the interaction of the beam charge and current with its electromagnetic environment is presented. The theory allows to numerically calculate the threshold current for an arbitrary frequency versus momentum curve. The numerical ...
The physics and numerical aspects of the development of the computer code QUARTZ are given. This code includes the (1) use of a finite element code to obtain solutions of Poisson's equation in an asymmetric, three-dimensional volume; (2) inclusion of space charge neutralization by electrons; and (3) inclusion of ion space charge through an ...
A method is described for the calculation of aerodynamic loads on a horizontal axis wind turbine rotor. The method is based upon acceleration potential theory. An approximate solution of the boundary value problem has been obtained using a matched asymptotic expansion technique. Furthermore a numerical integration procedure has been ...
Radiation can have a dramatic effect on the material properties of low density plasmas, altering bulk properties such as energy density and specific heat as well as spectral characteristics such as opacity and emissivity. The response of the material to radiation must be considered when constructing transport algorithms that are intended to provide self-consistent solutions ...
Many high energy solar energetic particles (SEPs), potentially threatening astronauts and instruments on space missions, are considered to be accelerated by CME-driven shocks in interplanetary space. So that it is important to know the mechanisms of space energetic particles transport with acceleration of CME-driven shocks. But they still remain a puzzle ...
Influence of Alfven wave nonlinear interaction on the solar wind ion acceleration at the Earth's bow shock is studied on the basis of numerical solution of selfconsistent transport equations. It is shown that nonlinear interaction of selfexcited Alfven waves due to the induced scattering and two-quantum absorption essentially restricts ...
Analytical and numerical calculations are presented for a reflexing electron beam type of collective ion accelerator. These results are then compared to those obtained through experiment. By constraining one free parameter to experimental conditions, the self-similar solution of the ion energy distribution agrees closely with the ...
Soil erosion may well be the world's most serious environmental problem. A variety of human activities accelerates the rate of this geomorphie process by altering the natural characteristics of a site. The problems arising from accelerated erosion and subsequent deposition provide numerous research opportunities to both physical and ...
Multiplicative programming problems with exponent (MPE) have many practical applications in various fields. In this paper, a method for accelerating global optimization is proposed for a class of multiplicative programming problems with exponent under multiplicative constraints using a suitable deleting technique. This technique offers the possibility of cutting away a large ...
We consider a nonrelativistic quantum charged particle moving on a plane under the influence of a uniform magnetic field and driven by a periodically time-dependent Aharonov�Bohm flux. We observe an acceleration effect in the case when the Aharonov�Bohm flux depends on time as a sinusoidal function whose frequency is in resonance with the cyclotron frequency. In ...
... A numerical solution for the model is described and a ... REPRINTS, DISPERSING, NUMERICAL ANALYSIS, SOLUTIONS(GENERAL), PULSES ...
... Title : The Numerical Solution of Compressible Fluid Flow Problems. ... Solutions include subsonic and supersonic velocity regions and transition ...
... the numerical solution of nonlinear elliptic partial ... elliptic equations; The numerical solution of some ... Approximate regularized solutions to improperly ...
... algorithm, in which independent solutions on a ... merged until the full solution is obtained. ... of the construction and the resulting numerical scheme will ...
... of linearly inde pendent solutions of the homogeneous equation in terms of which the desired solution is expressed. Numerical examples are given. ...
... The impact of parameter dependent boundary conditions on the solutions of a ... of computation, we proposal to find the numerical solution of the ...
... an adequate approximation to the solution. ... the previously discussed numerical techniques, we ... descriptions of the solutions are summarized in ...
... now � 7% of the relative error in the solution at 50% of the random noise in the data. Thus, the high accuracy of numerical solutions cannot be ...
... of numerical methods capable of yielding accurate solutions of the kinetic ... The free polecule solution to the circular cylinder problem has �. ...
... The comparisons show the numerical solution to be very ... THESES, TURBULENT FLOW, SURFACES, SOLUTIONS(GENERAL), AXISYMMETRIC ...
... Of particular interest here is the numerical solution of the so ... dimensional upwind equations requiring three block tridiagonal solutions similar to ...
... It is the intent of this study to obtain unified solutions of equations (8) on the basis of an ... NUMERICAL SOLUTION OF DIFFERENTIAL EgUATIONS ...
... identically to Newton's method as applied to the solution of nonlinear ... these computations are compared with previous numerical solutions as well ...
In this paper, a semi-exact method is applied to solve the off-centered stagnation flow towards a rotating disc. A similarity transformation reduces the Navier�Stokes equations to a set of nonlinear ordinary differential equations which are solved analytically by means of homotopy analysis method (HAM). Two auxiliary parameters are applied to accelerate the convergence of ...
In this paper, accelerated power series solutions are developed for N-dimensional symmetric radially polytropes. The solutions are valid for any geometric and polytropic index. The implementation of Pad\\acute{e} technique and changing of the independent variable give us identical polytrope solutions to the ...
We demonstrate the existence of an additional class of stationary accelerating Airy wave forms that exist in the presence of third-order (Kerr) nonlinearity and nonlinear losses. Numerical simulations and experiments, in agreement with the analytical model, highlight how these stationary solutions sustain the nonlinear evolution of ...
We propose in this paper to demonstrate the impact of mesh adaptation technology on computational fluid dynamics (CFD) solution accuracy. A global methodology is presented that includes a selected number of pre-processing techniques that sensibly improve the quality of the initial meshes and accelerate the solution-adaptation process. ...
The analytical solution of the system of coupled ordinary differential equations which describes the time evolution of an ideal coaxial plasma gun operating in the snowplow mode is obtained in the weak coupling limit, i.e., when the gun is fully influenced by the driving circuit but the circuit is negligibly influenced by the gun. Criteria are derived for the validity of this ...
The sine-Gordon model with a variable mass (VMSG) appears in many physical systems, ranging from the current through a nonuniform Josephson junction to DNA-promoter dynamics. Such models are usually nonintegrable with solutions found numerically or perturbatively. We construct a class of VMSG models, integrable at both the classical and the quantum levels ...
A simulation code has been written to model the reconnection gun mass accelerator. The code includes the effects of magnetic flux diffusion and convection. The model is based on the solution of a 2-D time-dependent vector potential equation. This solution provides the magnetic force required to compute the self-consistent ...
The pick up and acceleration of all plasma electrons irradiated by an intense, subcyclic laser pulse is demonstrated via analytical and numerical calculations. It is shown that the initial low emittance of the plasma electrons is conserved during the process of acceleration, leading to an extremely cold, bunched electron beam. ...
The fields induced over a grating exposed to plane parallel light are explored. It is shown that acceleration is possible if either the particles travel skew to the grating lines, or if the radiation is falling at a skew angle onto the grating. A general theory of diffraction in this skew case is given. In one particular case numerical ...
We apply test-particle numerical simulations to model the acceleration of inner-source C+ by a strong interplanetary shock. The model consists of three distinct parts: (a) the distribution of inner-source pickup ions; (b) the initial acceleration of pickup ions (to produce seed particles) for a kinematically defined interplanetary ...
The dissertation is concerned with the use of iterative algorithms to obtain numerical solutions of large systems of linear algebraic equations with sparse matrices. Such systems often arise in the numerical solution of partial differential equations by finite difference methods and by finite element methods. The ...
... OF NUCLEAR REACTORS ON ELECTRON ... equations of reactor acceleration; solution of ... ELECTRIC POWER PRODUCTION, REACTOR KINETICS ...
... cycle of theoretical studies on particle capture under acceleration conditions in betatrons and synchrotrons contains mathematical solutions to this ...
... Title : ACCELERATED CRACK PROPAGATION OF TITANIUM BY METHANOL, HALOGENATED HYDROCARBONS, AND OTHER SOLUTIONS. ...
Tritium contamination reduction in small ion accelerators for neutron production, discussing pumping
... Accession Number : ADA218272. Title : Techniques for Accelerating Iterative Methods for the Solution of Mathematical Problems. ...
Accelerated sodium pyruvate decomposition in aqueous solution due to proteinoids produced by thermal
We solve for the behavior of cosmological perturbations in the Dvali-Gabadadze-Porrati (DGP) braneworld model using a new numerical method. Unlike some other approaches in the literature, our method uses no approximations other than linear theory and is valid on large scales. We examine the behavior of late-universe density perturbations for both the ...
Acceleration driven instabilities of fluid mixing layers include the classical cases of Rayleigh-Taylor instability, driven by a steady acceleration and Richtmyer-Meshkov instability, driven by an impulsive acceleration. Our program starts with high resolution methods of numerical simulation of two (or more) ...
We show how to accelerate the numerical solution of the Boltzmann equation for a binary gas mixture by using Graphics Processing Units (GPUs). In order to fully exploit the computational power of the GPU, we adopt a semi-regular method of solution which combines a finite difference discretization of the ...
Numerical solutions for pseudocompressible flows and compressible flows at low Mach numbers are obtained as substitutional solutions for incompressible flows. The governing equations are spatially discretized by central finite-difference approximations. The rational Runge-Kutta scheme is used for the time stepping scheme. The ...
Computational fluid dynamics solutions of the full Navier-Stokes equations have been used to numerically simulate the reacting in-bore flowfield for the ram accelerator projectile propulsion system. In this system a projectile is injected at supersonic velocity into a stationary tube filled with a pressurized mixture of hydrocarbon, ...
A numerical model for simulating the transient nonlinear behavior of 2-D viscous sloshing flows in rectangular containers subjected to arbitrary horizontal accelerations is presented. The potential-flow formulation uses Rayleigh damping to approximate the effects of viscosity, and Lagrangian node movement is used to accommodate violent sloshing motions. A ...
Analytical solutions are derived for both transient and steady state gradient distributions in the traveling wave (TW) accelerating structures with arbitrary variation of parameters over the structure length. The results of the unloaded and beam loaded cases are presented. Finally, the exact analytical shape of the rf pulse waveform was found in order to ...
... Also: (2) If a solution of a ... and positive solutions of a ... QUENCHING, ESTIMATES, NONLINEAR SYSTEMS, SOLUTIONS(GENERAL), BOUNDARY ...
... of Homogeneous and Heterogeneous Metallic Materials,. ... acceleration (active solution) or retardation (passivation ... main phase and enrichment of the ...
... Accession Number : AD0426253. Title : ANALYTICAL SOLUTION FOR CONSTANT ENTHALPY MHD ACCELERATOR,. ...
The phenomenon of high-amplitude inflation waves resulting from a sharp axial acceleration of the aorta, as may occur in road accidents, is investigated theoretically. The aorta is modeled as an axisymmetric tapered membranic shell (tube) made of an incompressible, nonlinear viscoelastic material with cylindrical orthotropy. It is filled with an inviscid, incompressible fluid ...
This paper examines the properties of a high intensity relativistic electron beam propagating between two grounded plane conductors, with particular emphasis on the implications for collective ion acceleration. The steady-state and time averaged equilibrium properties are obtained analytically, by employing a one-dimensional model. Numerical integration of ...
... The normal modes Em, (m - 1,..., L) are solutions of the generalized ... ka (17= 0) for both the analytic series solution and the numerical solution. ...
These three solutions and a numerical example are given. Numerical accuracy of the ... Choose smallest solution to quadratic solution or negative sign ...
NASA Website
In this article, the author considers a student exercise that involves determining the exact and numerical solutions of a particular differential equation. He shows how a typical student solution is at variance with a numerical solution, suggesting that the numerical ...
ERIC Educational Resources Information Center
