T.M. No. 7 - December 1964 



Interactions of the Beach-Ocean-Atmosphere System at Virginia 

 Beach, Virginia by W. Harrison and W. C. Krumbein 



A number of interactions among beach variables are investigated 

 by sequential linear multi-regression analysis as programmed for 

 high-speed computers. Study includes influence of beach geometry, 

 wave characteristics, tidal effects, and local wind conditions on 

 velocity of longshore currents, deposition and erosion on the lower 

 foreshore, and response of grain size and beach slope to shore 

 processes. Most-inf I uentia I combinations of variables arbitrarily 

 designated as "process" variables are in general agreement with 

 significant variables of wave-tank experimentation and substantiate 

 intuitive judgments regarding relative importance of these variables 

 on natural beaches. Results suggest that certain additional variables, 

 seldom examined under controlled conditions, be studied in combina- 

 tion with variables normally examined in wave tanks. Time lag 

 between inception of a group of "processes" and moment of their 

 maximum effect on the "response" is also investigated. 



T.M. No. 8 - December 1964 



Sedimentation at an Inlet Entrance, Rudee Inlet-Virginia Beach , 

 Virg inia by W. Harrison, W. C. Krumbein, W. S. Wilson 



A physical model is presented of the wave, longshore-current, 

 and ebb-tide current systems as they determine the distribution of 

 mean particle size and degree of sorting at the mouth of a con- 

 trol led inlet. Bottom samples taken at Rudee Inlet, Virginia Beach, 

 Virginia, were subjected to trend-surface analysis, to verify trends 

 predicted by model. Correspondence between model and natural situ- 

 ation was found to be good, but area of i n let -current influence was 

 found to be rather limited in extent. 



T.M. No. 9 - December 1964 



Dynamic Properties of Immersed Sand at Virginia Beach, Virginia 

 by W. Harrison and R. Morales Alamo 



Results are presented for a study designed to measure and 

 analyze systematic variations in mean settling velocity of a large 

 number of sand samples taken simultaneously along 3 transects across 

 the beach in the vicinity of Rudee Inlet. Measurements used to 

 describe properties of the samples were: mean settling velocity, 

 mean Reynolds number, and mean drag coefficient. Corey's shape 

 factor and Dynamic Shape Factor of Briggs, et al, were calculated 

 and compared. The importance of kinematic viscosity on dynamic 

 properties of sand particles and on beach slopes in shoa I ing-wave 

 zone is considered. Observed trends of mean size and sorting 

 throughout the dynamic zones are compared with those predicted 

 by Miller and Ziegler Model, but comparison is poor. 



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