WAVELENGTH, WAVE VELOCITY AND SHOALING CHARACTERISTICS OF RANDOM WAVES

Abstract

Fundamental properties of random waves determined by the zero-upcross method are discussed. Firstly, the wave length and the wave velocity are treated. Experiments are carried out with some supplemental definitions such as the spatial zero-up-cross method in a laboratory wave tank. Average values of K (= a ratio of measured wave length to theoretical one L /L , ) and R (= a ratio of measured wave velocity to e th J theoretical one C /C , ) are very close to unity though data are considerably scattered. But the relations between L <\< T and C ^ T are e e e e slightly different from the theoretical ones where T is the measured e wave period. Secondly , breaking characteristics on sloping beaches are treated. The wave height H, , the wave length L and the water depth h, are measured at a breaking point. Breaking characteristics of random waves are considerably different from those of periodic waves. The measured wave height-water depth ratio H, /h, is plotted against the water depth-wave length ratio h /L about 30 ^ 40% below the breaker inception curve for periodic waves.