simulation models of nearshore currents include extensive summaries of pre- 

 vious efforts (Lui and Mei, 1975; Oatendorf and Madsen, 1979; Ebersole and 

 Dalrymple, 1979; Vreugdenhil, 1980). 



The objectives of the work reported herein were to review and analyze 

 pertinent literature for the preparation of a state-of-the-art report includ- 

 ing major gaps in knowledge, data, and recommendations for future research. 

 Chapter 2 gives a physical description of coastal flows, including magnitudes 

 of currents measured in the field and the laboratory. The variability of 

 these currents in both space and time is of primary interest. Forcing func- 

 tions and mechanisms responsible for these currents are discussed. Instru- 

 ments and systems devised to measure the currents are also reviewed. In 

 Chapter 3 the fundamental equations, theory of longshore currents, and near- 

 shore circulation are summarized. Details of all theories before 1967 are 

 omitted. Both the time-averaged radiation stress theory and the new 

 "Boussinesq-type" theory are presented in considerable detail; however, full 

 derivations are not presented due to space limitations. Emphasis is on as- 

 sumptions and limitations of each theory. In many cases, assumptions are 

 made to permit analytical solutions of the appropriate equations. Numerical 

 solution methods allow relaxation of these assumptions but at the expense of 

 possible inaccuracies due to the researchers' discretion of the continuum. All 

 theories and solution methods rely heavily on many empirical and relatively 

 crude approximations in the surf zone. The chapter also includes the latest re- 

 search efforts to improve on fundamental knowledge in this regard. The ex- 

 perimental verification (or otherwise) of the theories is the subject of 

 Chapter 4. Unfortunately, the number of and complexities of the theories have 

 far outstripped the number and extent of good data sets to confirm (or reject) 

 them, so the state-of-the-art is then presented in this chapter. A brief 

 summary, conclusions, and recommendations are given in Chapter 5. 



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