Second Order Analysis Of Dynamic Pressure Profiles, Using MeasuredHorizontal Wave Flow Velocity Component

Abstract

There is an increasing need for pressure field knowledge under wave flows due to its importance in coastal structure design. Several studies have been conducted in such a way as to accurately learn the behavior of those pressure fields in trying to define reliable formulae for design purposes, describing with a better degree of detail the maximum values achieved as well as the stochastic aspects of the wave action. This article intends to present the evolution of pressure fields under the action of incident regular waves, as a function of its phase and relative depth, comparing them with a linear and a second order wave theory. These wave fields were obtained in an indirect way, through the horizontal wave flow velocity component. The measurements were carried out in the unidirectional wave tank of the Faculty of Engineering of the University of Porto. The wave tank was 4,8 m wide, 24,5 m long and has a maximum water depth of 0,40 m near the test section. Some profiles of the dynamic pressure are represented for each relative water depth (zld) and for different wave phases. The results obtained with the horizontal velocity component were compared with the results given by the theories and with the related values through the measured mean water elevations. The agreement between the different values is reasonable, especially for some wave phases. The differences could be explained by secondary or higher order effects.