The Emulation Research Of Wave Directional Spectrum Estimation

Wave directional spectrum represents wave energy distribution along with frequency and direction. It is a common measurement in ocean engineering, estimating wave directional spectrum is always a key question in ocean research.This thesis is based on linear theory. The ways of wave spectrum estimation, cross-spectrum estimation, and wave directional spectrum estimation are discussed.Now most researchers use MLM, EEV, MEP, BDM algorithms to estimate wave directional spectrum. The thesis use numerical emulation technology to estimate wave directional spectrum, which is basic work for future research. There are two kinds of numerical emulation ways: one is the emulation based on cross-spectrum, the other is the emulation based on wave model.Based on cross-spectrum emulation, for BDM and MLM algorithm, the effect of spacing between gauges is studied and also the directional spreading assumption, the number of gauges, the error of cross-spectrum analysis.For buoy, arrays and ADCP, the wave directional spectrum is studied based on wave model. Since ADCP is relatively new equipment of getting wave directional spectrum, we mostly concerns 'surface tracking' and 'velocity cell matrix'.The emulation result shows that ADCP has high estimation precision of arrays, and it is also easy to handle just like buoy. ADCP has wide application in estimating wave directional spectrum.