Source Term Balance for Finite Depth Wind Waves

Abstract : LONG-TERM GOAL. The long-term goal is to obtain closure of the energy balance equation for wind wave evolution in finite depth water by means of direct measurement of the main source terms. These source terms represent the basic physical processes required to develop reliable finite depth wave prediction models. SCIENTIFIC OBJECTIVES. The objectives are to establish a description of the basic sources/sinks of energy responsible for shallow water wind wave evolution, namely dissipation due to both wave breaking and bottom friction, and wind input. Spectral distribution of white-capping dissipation has not previously been obtained either experimentally or theoretically, and currently speculative approaches are used to represent this term in wave models. The natural phenomena determining this term are random, nonlinear and related to extreme wave conditions and hence are difficult to evaluate in the field. The other two terms have been the subjects of intensive research during the last three decades, although detailed field observations are rare. There is a qualitative understanding of their behaviour, however, no established quantitative description is available.