Chinese English

A WAVE that occurs within a fluid whose DENSITY changes with DEPTH, either abruptly at a sharp surface of discontinuity (an INTERFACE) or gradually. Also called boundary wave.

A TRANSVERSE WAVE propagated along the BOUNDARY of two elastic media which both have rigidity, i.e. both media must be capable of propagat­ing TRANSVERSE WAVES. A surface seismic wave in which the particles of an elastic medium vibrate transverse to the direction of the WAVE's travel, with no vertical component.

A WAVE in which each individual particle oscillates about a point with little or no permanent change in position. The term is commonly applied to progressive oscillatory waves in which only the form advances, the individual particles moving in closed ORBITS, as ocean waves in deep waters. Distin­guished from a WAVE OF TRANSLATION.

ELECTROMAGNETIC WAVES of FREQUENCIES generally higher than those of audible SOUND WAVES but lower than those of heat and light waves. Also called hertzian waves.

A RADIO WAVE shorter than those of the standard broadcasting band. In OCEANOGRAPHY, WAVES under conditions where the relative DEPTH (water depth/wave length) is greater than 0.5 and where the PHASE VELOCITY is independent of water depth, but dependent upon WAVE LENGTH.

An indirect RADIO WAVE which travels from the transmitting ANTENNA into the sky, where the IONOSPHERE bends it back toward the EARTH. Also called ionos­pheric wave. See WAVE: GROUND.

A WAVE OF TRANSLATION consisting of a single CREST rising above the undisturbed liquid level, without any accompanying TROUGH, in contrast with a WAVE TRAIN.

A mechanical disturbance advancing with finite VELOCITY through an elastic medium and consisting of longitudinal displacements of the ultimate particles of the medium, that is, consisting of compressional and rare-factional displacements parallel to the direction of advance of the disturbance; a LONGITUDINAL WAVE. Also called sonic wave, or acoustic wave.

A type of WAVE in which the surface of the water oscillates verti­cally between fixed points, called NODES, without progression. The points of maxi­mum vertical RISE and fall are called antinodes or LOOPS. At the NODES, the underlying water particles exhibit no vertical motion but maximum horizontal motion. At the antinodes the underlying water parti­cles have no horizontal motion and maximum vertical motion. They may be the result of two equal progressi­ve WAVE TRAINS travelling through each other in opposite direc­tions. Also called stationary wave.