conservation of mass to the mechanics of granular- fluid media. This 

 hypothesis appears to have general application to transport processes 

 in the littoral zone. 



83. IWASAKI, T., and NUMATA, A., "Experimental Studies on Wave Transmis- 

 sion of a Permeable Breakwater Constructed by Artificial Blocks," 

 Coastal EngineeTing in Japccn^ Tokyo, Japan, Vol. 13, 1970, pp. 25-29. 



Keywords: Hydraulic model (two-dimensional). Permeable breakwater, 

 Wave attenuation. Wave transmission 



When a breakwater is composed of artificial blocks, waves can pass 

 easily through it. However, wave energy is dissipated and the wave 

 height is decreased. This paper deals with the transmission rate of 

 wave height, i.e., the ratio of the transmitted wave height H^ to the 

 incident wave height H-, and the rate of energy dissipation. It was 

 found by experiments that H^/H^ depends only on incident wave steepness 

 for the breakwater when the crest height above the Stillwater level h 

 is larger than H^. However, when h^ is smaller than H^, H^/H^ de- 

 pends on both the incident wave steepness and the Reynolds number defined 

 ^y ^max^o^^' w^®^® ^max ^^ ^^^ maximum horizontal velocity at the 

 Stillwater level. The energy dissipation is expressed as a function of 

 the incident wave steepness, but its expression is different for the 

 above two cases . 



84. JAPAN MINISTRY OF TRANSPORT, PORT AND HARBOR BUREAU, "Kowan Kozobutsu 

 Sekkei Kijun" (Design Standard for Port and Harbor Structures), Sept. 

 1968, pp. 11-13 (in Japanese). 



Keywords: Local scour. Vertical breakwater 



85. JAPAN SOCIETY OF CIVIL ENGINEERS, Design Manual for Shore Protection^ 

 Sec. 3, June 1957, pp. 199-219 (in Japanese). 



Keywords: Accretion, Armor units, California (Santa Monica), Composite 

 structures, Concrete structures. Detached breakwater, Down- 

 drift beaches. Foundation design, Italy (Loano and Posillipe), 

 Littoral transport, Local scour. Permeable breakwater. Rubble 

 mound. Segmented breakwater, Structural dimensions. Structure 

 settlement. Submerged breakwater, Torabolo, Wave attenuation. 

 Wave diffraction. Wave overtopping. Wave transmission 



Various aspects of the design of detached breakwaters are discussed. 

 Among these are the spacing, length, crest height, and offshore distance. 

 Construction precautions are outlined and descriptions are given of the 

 various structural types that can be used. Two design examples are pro- 

 vided for a vertical concrete structure and a rubble-mound structure. 



86. JAPAN SOCIETY OF CIVIL ENGINEERS, Kaigan Hozen Shisetsu Sekkei 

 Benran (Handbook for Coastal Protection and, Facility Designs), 

 Tokyo, Japan, July 1969, pp. 102-106, 241-249 (in Japanese). 



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