HR: 0800h
AN: OS21A-02    [Abstracts]
TI: Identifying the types of waves: A value adding study on the ocean observing data buoy system
AU: * Ramakrishnan, B
EM: rbalaji@iitm.ac.in
AF: Research Scholar, Department of Ocean Engg., Indian Institute of Technology Madras, Chennai, TN 600036, India
AU: Sannasiraj, S
EM: sasraj@iitm.ac.in
AF: Associate Professor, Department of Ocean Engg., Indian Institute of Technology Madras, Chennai, TN 600036, India
AU: Sundar, V
EM: vsundar@iitm.ac.in
AF: Professor, Department of Ocean Engg., Indian Institute of Technology Madras, Chennai, TN 600036, India
AB: Understanding of the wave climate in a particular place of interest is one of the primary aspects of any ocean observing system. Engineers and scientists working in the area of coastal or offshore engineering require to have knowledge on the types of waves that predominantly prevailing not only for the design of the ocean structures but also to understand the physical behavior of ocean surface. For example, identification of breaking waves is given prime importance as it has potential to answer for many of the water-air interaction or turbulence mixing problems. On the other hand, group of waves in which successive wave heights exceed the significant value could exert tremendous forces on the ocean structures and may lead catastrophic damage to it. Apart from deriving the conventional information such as the significant wave periods, heights and the predominant direction of prevailing, knowledge on the existence of type of waves would certainly help the designers, engineers and researchers. In an attempt to classify the types of waves from the buoy measurements, a detailed experimental program was conducted in the Department of Ocean Engineering, Indian Institute of Technology Madras. The buoy model was subjected to variety of waves such as group and breaking waves. The challenging task of the study is to simulate the group and breaking waves in the controlled laboratory environment. For which, initially, these waves are simulated theoretically, which intern converted into first order wave paddle signals to simulate the waves in the flume. The buoy heave, surge and pitch motions were measured by using potentiometers and the non-contact motion capturing cameras. The experimentally obtained wave elevation and the buoy motions time histories were analyzed by statistical, continuous wavelet transformation and phase-time methods to find the traces of wave types. A careful step by step analysis of the buoy motions yields presence of wave groupiness and breaking events. The details of the model, instrumentation, testing conditions and the analysis are presented and discussed in this paper.
DE: 3270 Time series analysis (1872, 4277, 4475)
DE: 3280 Wavelet transform (3255, 4455)
DE: 4262 Ocean observing systems
DE: 4534 Hydrodynamic modeling
SC: Ocean Sciences [OS]
MN: 2007 Joint Assembly