Critical Wave Conditions for Sand Motion Initiation

Source: https://erdc-library.erdc.dren.mil/jspui/Sand and fluid characteristics together with the period of oscillatory flow determine the peak fluid velocity needed for sand motion initiation. With linear wave theory, this threshold peak near-bottom velocity can be used to calculate critical wave conditions for sand motion-either the minimum wave height in a given water depth, or the maximum water depth with a given wave height, for a given wave period. The procedure presented here permits prediction of the seaward extent of bed activity due to wave action in field and laboratory situations. Example calculations are provided

Seaward Limit of Significant Sand Transport by Waves: An Annual Zonation for Seasonal Profiles

Source: https://erdc-library.erdc.dren.mil/jspui/Sand characteristics and annual wave statistics at a site are used to determine two water depths bounding a shoal zone on the beach profile. This zonation is based on two thresholds of wave-induced sand agitation, so that expected waves during a year have neither strong nor negligible effects on the sand bottom within the shoal zone. The calculation procedure and representative results for the shoal zone bounds are presented to supplement techniques for estimating a seaward limit of significant sand transport given in the Shore Protection Manual (SPM) . A calculator program is provided

Calculation of Wave Shoaling with Dissipation over Nearshore Sands

Source: https://erdc-library.erdc.dren.mil/jspui/This report provides a simplified calculation procedure for nearshore wave height changes considering the energy dissipated by rough turbulent flow over a strongly agitcted bed of quartz sand. All elementary wave relationships are from linear monochromatic wave theory, but one effect of including dissipation is that calculated height changes depend on the absolute wave height. The general effect of appreciable energy loss is to make field wave height relatively constant outside the breaker zone. Example computations and a calculator program are provided

Wave Transformation at Isolated Vertical Piles in Shallow Water

Source: https://erdc-library.erdc.dren.mil/jspui/Water level was measured within the flanges of a channeled pile, or near the surface of a circular pile, for isolated piles in a periodic wave train. Measurements are plotted as 160 patterns of crest height versus orientation with respect to wave direction. All patterns have a maximum at the front, facing into the wave, and a lesser maximum at the rear. Intervening minimums are symmetrically located at the sides of the pattern, usually slightly toward the rear. As wave height increases, the front maximum becomes higher, depending on calculated velocity head. The angular width of the front maximum depends on channel geometry of the pile, tending to be very broad for a pile without channels and narrow for a pile with deep channels. With H-piles having deep channels, the pattern minimums occur farther forward than with unchanneled piles. Geometrically similar piles of different size result in similar patterns. The patterns for finned and smooth circular piles are similar, except that the finned pile results in slightly higher and narrower front and rear maximums. Applications of the reported conclusions to the design of nearshore pilesupported structures are briefly discussed. Twelve different vertical piles were tested, including circular, circular with radial fins, and various H-sections. Pile cross section and water depth were small compared to wavelength, corresponding to typical nearshore situations. Electrical gage records and photos show complicated surface effects occur near the piles. Crest stagnation can be similar at circular and channeled piles with three stagnation regimes: smooth, breaking, and jetting runup. Smooth runup occurred in most tests, with a nonbreaking bow wave formed at the front of the pile during peak forward flow

Calculation of wave shoaling with dissipation over nearshore sands /

"March 1983."Distributed to depository libraries in microfiche.Cover title.Bibliography: p. 16.Mode of access: Internet.2 1