Journal of Waterway, Port, Coastal, and Ocean Engineering

A wave tank test was performed on fixed vertical and inclined cylinders in which forces on the cylinder in regular waves were measured. The hydrodynamic coefficients are computed based on the measured local forces on the cylinder, Morison equation and stream function theory. The inertia and drag forces are shown as functions of the Keulegan‐Carpenter number. The lift coefficients and lift force frequencies are presented as functions of the Keulegan‐Carpenter number. The coefficients obtained locally are shown to generally apply to the entire cylinder based on the respective local KC values.

A simplified analytic investigation of the local suspended sediment transport in the onshore‐offshore mode is performed, and is then adapted for computer solution to model beach profile evolution. The transport scheme involves both first order wave induced and mean “return flow” currents, coupled With an exponentially shaped sediment concentration profile. Five criteria for a “good” model are established, four of which are at least qualitatively satisfied by the present work. The model generates profiles of either the normal or storm types, depending on the wave conditions and sediment characteristics. The normal profiles are monotonic and concave upwards while the storm profiles contain one or more bars. The model responds to changes in water level due to tides, storm surge, or long‐term fluctuations, and the relative rates of profile evolution appear to be correct. More research is required before quantitative accuracy can be achieved.

In selected laboratory tests of sand slope development by waves, the elevations of two types of subaqueous wave‐cut feature are explained by quantitative thresholds in wave‐sand interactions. One feature is a seaward limit to nearshore‐eroding wave processes, and the other is a seaward limit to constructive wave effects. These two calculable water depths usually define the extent of moderate sand agitation by shoaling waves. The basic type of wavedeveloped profile is found to depend on sand settling velocity and wave characteristics at the erosive wave cut, but not on details of surf processes as measured by a surf‐similarity number. These results, together with available knowledge of the equilibrium profile, are examined to define some requirements for an accurate model of the active nearshore sediment bed. With quartz sand in water and Froude‐scaled waves, a model would require an unusually long and deep wave tank. Several modeling compromises appear necessary in the planar profile segment of moderate bed agitation, so that restricting laboratory models to the curved shoreface profile segment seems advisable.

Along the ocean coasts of the continental USA there are 124 sea ports, 73 of which handle significant volumes of freight. All ports are important economic components of local regions but the role of medium sized ports in the nation's transportation system is not as clear as that of large ports. Using a classification based on value of cargo, 21 large, 24 medium, and 28 small ports are identified and the roles of the medium ports are investigated. Thirteen of the medium ports have container handling facilities; ten concentrate only on bulk cargos. Bulk cargos are the mainstay of most of the medium ports and they are vulnerable to changes in demand for transportation of bulk commodities and to competition from new large‐scale facilities. Medium ports handle 10%–37% of the totals for the ocean coasts in each of five bulk cargo categories. They play a lesser role in containerized transportation, handling only about 6‐1/2%. This role however is vitally important to the 13 medium ports that have container facilities.

A parabolic model for calculating the combined refraction/diffraction of monochromatic linear waves is developed, including a term which allows for the dissipation of wave energy. The coefficient of the dissipation term is related to a number of dissipative models. Wave calculations are performed for a localized area of dissipation, based on a friction model for a spatial distribution of rigid vertical cylinders. The region of localized dissipation creates a shadow region of low wave energy, which may have important implications for the response of neighboring shore lines.

A summary of design criteria for granular filters, complemented by extensive recent experimental data, is presented. Distinction is made between granular filter constructions subject to steady or cyclic flow, parallel or perpendicular to the interface between the fine base material and the coarse filter material. Some combinations of those flow situations are also considered. Some physical explanation of the filter action is given, together with new experimental data on: (1) The influence of a superimposed load on the behavior of granular filters; and (2) the internal stability of graded filter materials.