Estimation of directional wave spectrum using a wave-probe array

Abstract

This paper discusses the evaluation of a series of multidirectional waves generated at the LabOceano wave basin. The methodology adopted follows the one proposed by Stansberg (1998), using an array of eight wave-probes. A computational routine was developed for the estimation and a preliminary validation was obtained in a numerical analysis. In this case, the wave spectra were known, and problems related to measurement noise were not considered. Such preliminary analysis showed that the method was able to estimate the directional spectrum precisely, considering short and long crested unimodal waves and also bimodal waves. The statistical parameters (significant wave height, peak period), mean direction and spreading functions were estimated with very good accuracy. The method was then applied to a full set of experiments in the LabOceano wave tank. Short and long crested unimodal waves and also bimodal waves were generated. The maximum entropy inference method was then used to estimate the directional wave spectrum, and to compare it with the spectrum used as the input for the wave generator. The results showed a very close proximity between required and measured results, both for statistics and directional spreading functions.