3.1: Introduction

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Page ID: 16180

Judith Bosboom & Marcel J.F. Stive
Delft University of Technology via TU Delft Open

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This chapter deals with ocean waves. By ocean waves we mean all oscillations of the water surface generated in the ocean (see Sect. 3.2). The most important in shaping the coastal zone are the short waves generated by wind and the longer tidal motion generated by the attractive forces of the sun and the moon on the water masses of the earth. In Sect. 3.3 we look at how waves can be measured. Statistical and spectral representations of wind waves are treated in Sect. 3.4. Both wind wave generation and the propagation away from the area of wave generation are treated in Sect. 3.5. We see how ocean waves become longer and smaller when propagating away further from their source due to the phenomenon of wave frequency dispersion and due to frequency dependent dissipation. Long term statistics are briefly discussed in Sect. 3.6. The generation of the tide is explained and the origin of the different harmonic constituents is treated in Sect. 3.7. We look into the propagation of the tide in the world’s oceans and in doing so talk about propagation velocity, Coriolis forces and amphidromic systems (Sect. 3.8). Tidal analysis and prediction are the topics of Sect. 3.9.

After having taken the DUT courses Ocean Waves (CIE4325), Hydraulic Engineering (CTB2410, in Dutch) and Open Channel flow (CTB3350/CIE3310-09) the larger part of this chapter on Ocean Waves should be familiar to you. This particularly holds for the Sects. 3.2 to 3.6 on wind or short waves. You will find that Sects. 3.7 to 3.9 treat the tidal generation and propagation more extensively than CTB2410 does. In CTB3350/CIE3310-09 you will have encountered some aspects of tidal propagation as well. For those of you without any prior knowledge of wind waves or tides in oceanic waters, this chapter deals with the main aspects that are required in order to successfully follow Coastal Dynamics I (CIE4305).