河床波スペクトルの発達に関する研究

Abstract

In this study, the mechanism of sand wave formation is investigated based on inspecting the timevariation of wave number spectra of bed surface. There are three processes in spectral evolution ofsand waves; (1) variance production process based on random repetitions of dislodgement and deposi-tion of bed particles, (2) amplification of favorable wave number range spectra based on bed instabilitymechanism, and (3) variance cascade process based on the phenomenon that individual sand waves areunified on overtaking each other. Particularly, the latter two subprocesses are significant for formingthe characteristics of sand wave spectra, and they are minutely inspected. Furthermore, someexperiments in a rectangular closed conduit are conducted in addition to those in an open channelfor inspections of the mechanism of spectral evolution of sand waves.