64 research outputs found
A Vectorized Algorithm for Molecular Dynamics of Short Range Interacting Particles
We report on a lattice based algorithm, completely vectorized for molecular
dynamics simulations. Its algorithmic complexity is of the order O(N), where
is the number of particles. The algorithm works very effectively when the
particles have short range interaction, but it is applicable to each kind of
interaction. The code was tested on a Cray ymp el in a simulation of flowing
granular material.Comment: 9 pages, 6 figures, Late
Kinetic Integrals in the Kinetic Theory of dissipative gases
The kinetic theory of gases, including Granular Gases, is based on the
Boltzmann equation. Many properties of the gas, from the characteristics of the
velocity distribution function to the transport coefficients may be expressed
in terms of functions of the collision integral which we call kinetic
integrals. Although the evaluation of these functions is conceptually
straightforward, technically it is frequently rather cumbersome. We report here
a method for the analytical evaluation of kinetic integrals using computer
algebra. We apply this method for the computation of some properties of
Granular Gases, ranging from the moments of the velocity distribution function
to the transport coefficients. For their technical complexity most of these
quantities cannot be computed manually.Comment: 32 page
Rolling as a continuing collision
We show that two basic mechanical processes, the collision of particles and
rolling motion of a sphere on a plane, are intimately related. According to our
recent findings, the restitution coefficient for colliding spherical particles
\epsilon, which characterizes the energy loss upon collision, is directly
related to the rolling friction coefficient \mu_{roll} for a viscous sphere on
a hard plane. We quantify both coefficients in terms of material constants
which allow to determine either of them provided the other is known. This
relation between the coefficients may give rise to a novel experimental
technique to determine alternatively the coefficient of restitution or the
coefficient of rolling friction
- …