Early Attempts With A Square Lattice
In papers published in 1973 and 1976, Hardy, Pomeau and de Pazzis introduced the first Lattice Boltzmann model, which is called the HPP model after the authors. In this model, the lattice is square, and particles can move to any of the four sites whose cells share a common edge. Particles cannot move diagonally.
If two particles collide head-on, for example a particle moving to the left meets a particle moving to the right, the outcome will be two particles leaving the site at right angles to the direction they came in.
The HPP model lacked rotational invariance, which made the model highly anisotropic. This means for example, that the vortices produced by the HPP model are square-shaped.
Read more about this topic: Lattice Gas Automaton
Famous quotes containing the words early, attempts and/or square:
“Early education can only promise to help make the third and fourth and fifth years of life good ones. It cannot insure without fail that any tomorrow will be successful. Nothing “fixes” a child for life, no matter what happens next. But exciting, pleasing early experiences are seldom sloughed off. They go with the child, on into first grade, on into the child’s long life ahead.”
—James L. Hymes, Jr. (20th century)
“Prohibition will work great injury to the cause of temperance. It is a species of intemperance within itself, for it goes beyond the bounds of reason in that it attempts to control a man’s appetite by legislation, and makes a crime out of things that are not crimes. A Prohibition law strikes a blow at the very principles upon which our government was founded.”
—Abraham Lincoln (1809–1865)
“Rationalists, wearing square hats,
Think, in square rooms,
Looking at the floor,
Looking at the ceiling.
They confine themselves
To right-angled triangles.”
—Wallace Stevens (1879–1955)