CONTENTS 



FIGURES — Continued 



Page 



5 Time history of longshore velocity and wave height in surf zone 



of North Sea, Isle of Sylt, Germany, November 1973 31 



6 Temporal variations of averaged longshore currents at five locations 



in surf zone, Torrey Pines Beach, California, March 1977 32 



7 Time history of averaged longshore current from five closely spaced 



current meters, Scripps Beach, La Jolla, California, July 1978 33 



8 Wave-generated current system behind offshore breakwater 35 



9 Vertical velocity distribution at profile section I for (a) longshore 



current and (b) onshore-offshore current 37 



10 Uniform, depth-averaged longshore current profiles and circulation 



velocities under optimum conditions of minimum circulations, 



adjusted return flows , and upstream distribution system 40 



11 Measurements in wave basin with only surf zone openings in both 



waveguides and free recirculation 40 



12 Nearshore current classification system 42 



13 Beach classification system, showing (a) a reflective beach and 



(b) a dissipatlve beach 46 



14 Positioning of rip currents at alternate antinodes of standing edge 



waves on a plain beach with regular incident swell waves 50 



15 Schematic of drogue used by Japanese 55 



16 Gain response of flow meters for pseudorandom noise runs, single- 



frequency runs , and towed values 57 



17 Schematic of BAGS nearshore current system 59 



18 Location of EM current meters and other instruments in NSTS, 



Torrey Pines, California, experiment 61 



19 Definitions and nomenclature for radiation stress components 67 



20 Mohr's Circle analysis 71 



21 Schematic of wave setdown and setup due to normal wave incidence 



on a plain beach 73 



22 Circulation current in breaker zone 78 



23 Schematic of refracted oblique wave incidence on a plane infinite 



beach showing resulting longshore current profile and MWL changes.... 81 



7 



