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Full-Text Articles in Ordinary Differential Equations and Applied Dynamics

Monotone Solutions Of A Nonautonomous Differential Equation For A Sedimenting Sphere, Andrew Belmonte, Jon T. Jacobsen, Anandhan Jayaraman Sep 2001

Monotone Solutions Of A Nonautonomous Differential Equation For A Sedimenting Sphere, Andrew Belmonte, Jon T. Jacobsen, Anandhan Jayaraman

All HMC Faculty Publications and Research

We study a class of integrodifferential equations and related ordinary differential equations for the initial value problem of a rigid sphere falling through an infinite fluid medium. We prove that for creeping Newtonian flow, the motion of the sphere is monotone in its approach to the steady state solution given by the Stokes drag. We discuss this property in terms of a general nonautonomous second order differential equation, focusing on a decaying nonautonomous term motivated by the sedimenting sphere problem


Simulation Of Engineering Systems Described By High-Index Dae And Discontinuous Ode Using Single Step Methods, Marc Compere Aug 2001

Simulation Of Engineering Systems Described By High-Index Dae And Discontinuous Ode Using Single Step Methods, Marc Compere

Publications

This dissertation presents numerical methods for solving two classes of or-dinary diferential equations (ODE) based on single-step integration meth-ods. The first class of equations addressed describes the mechanical dynamics of constrained multibody systems. These equations are ordinary differential equations (ODE) subject to algebraic constraints. Accordinly they are called differential-algebraic equations (DAE).

Specific contributions made in this area include an explicit transforma-tion between the Hessenberg index-3 form for constrained mechanical systems to a canonical state-space form used in the nonlinear control communities. A hybrid solution method was developed that incorporates both sliding-mode control (SMC) from the controls literature and post-stabilization from …


Interfering Solutions Of A Nonhomogeneous Hamiltonian System, Gregory S. Spradlin Jan 2001

Interfering Solutions Of A Nonhomogeneous Hamiltonian System, Gregory S. Spradlin

Greg S. Spradlin Ph.D.

A Hamiltonian system is studied which has a term approaching a constant at an exponential rate at infinity. A minimax argument is used to show that the equation has a positive homoclinic solution. The proof employs the interaction between translated solutions of the corresponding homogeneous equation. What distinguishes this result from its few predecessors is that the equation has a nonhomogeneous nonlinearity.


Numerical Solution Of Fuzzy Differential Equation By Runge-Kutta Method, S. Abbasbandy, T. Allah Viranloo Jan 2001

Numerical Solution Of Fuzzy Differential Equation By Runge-Kutta Method, S. Abbasbandy, T. Allah Viranloo

Saeid Abbasbandy

In this paper numerical algorithms for solving 'fuzzy ordinary differential equations' are considered. A scheme based on the 4th Runge-Kutta method in detail is discussed and this is followed by a complete error analysis. The algorithm is illustrated by solving some linear and nonlinear fuzzy Cauchy problems.


Numerical Solution Of Fuzzy Differential Equation By Runge-Kutta Method Of Order 2, S. Abbasbandy, T. Allah Viranloo Jan 2001

Numerical Solution Of Fuzzy Differential Equation By Runge-Kutta Method Of Order 2, S. Abbasbandy, T. Allah Viranloo

Saeid Abbasbandy

In this paper numerical algorithms for solving 'fuzzy ordinary differential equations' are considered. A scheme on the 2nd Rung-Kutta method in detail is discussed and this is followed by a complete error analysis. The algorithm is illustrated by solving some linear and nonlinear fuzzy Cauchy problems.


An Analysis Of Unsolvable Linear Partial Differential Equations Of Order One, Laura J. Fields Jan 2001

An Analysis Of Unsolvable Linear Partial Differential Equations Of Order One, Laura J. Fields

Inquiry: The University of Arkansas Undergraduate Research Journal

It is difficult to underestimate the importance of differential equations in understanding the physical world. These equations, involving not just simple variables like temperature, speed or mass, but also the derivatives, i.e. the rate of change of these variables, are found in nearly every branch of science. Until the mid 20th century, all such equations were thought to be solvable. This was based on the discovery by Leonard Euler that certain differential equations, called ordinary differential equations (ODEs), are indeed always solvable. While ODEs deal with simple conditions, under which some quantity changes with some other quantity and its derivatives, …