1. Introduction 2. Observation techniques 3. Description of ocean waves 4. Statistics 5. Linear wave theory (oceanic waters) 6. Waves in oceanic waters 7. Linear wave theory (coastal waters) 8. Waves in coastal waters 9. The SWAN wave model Appendices References Index.

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Waves in Oceanic and Coastal Waters

The growth of fetch limited waves in water of finite depth. Part 1. Total energy and peak frequency

Shore Protection Manual

Approaches for recreating hurricane surface winds in relation to ocean wave, surge, and current modeling are reviewed. A discrete numerical wind field model, based on original developments at New York University in the early 1970s and used extensively by the U.S. Army Corps of Engineers (CE) and others, is described in detail. Limitations of the model are also discussed. The CE model for hurricane surface wind fields has been a very useful tool in ocean response (OR) modeling for more than a decade. Recently, several aspects of the model were upgraded, including increased spatial resolution and capabilities for simulating a wider variety of radial pressure and wind profile forms. The upgraded features of the model are described, and their impact on hurricane simulations is illustrated with a hypothetical hurricane and with hurricanes Camille (1969) and Gilbert (1988). The upgrades are expected to lead to improvements in the accuracy of OR modeling, particularly for small, intense hurricanes and for well-documented storms with broad and/or multipeaked radial wind profiles.

Practical Modeling of Hurricane Surface Wind Fields

Wave attenuation by flexible, idealized salt marsh vegetation

The transformation of monochromatic and directionally-spread irregular waves passing over a submerged elliptical mound was studied in a controlled laboratory experiment. A directional spectral wave generation was used to generate waves with equal peak frequencies and spectral energy, along with monochromatic waves of equivalent significant height and period. Spectra with both narrow and broad frequency and directional spreads were generated. Results indicate that monochromatic waves provide a poor approximation of irregular wave conditions if there is directional spread or high wave steepness.

Refraction-diffraction of irregular waves over a mound

A three-dimensional, physical model study of wave diffraction around a semi-infinite breakwater was conducted using a directional spectral wave generator. Both regular and irregular waves with narrow and broad frequency and directional spreading were simulated. Surface elevations were measured in the lee of the breakwater, within a radius of three wavelengths of the tip. Comparisons with regular and irregular wave prediction methods indicate the strengths and limitations of the methods for various wave conditions, and the importance of directional spreading. Data are given to assist other investigators in testing numerical models.

Wave Diffraction around Breakwater

Wave height parameters used in coastal and ocean engineering are grouped into three classes according to their definition bases: height statistics, energy, and monochromatic. Parameters within each class are easily interrelated for most engineering purposes. However, parameters from different classes are difficult to interrelate, particularly for shallow water applications where waves are near breaking. The often-used parameter “significant wave height” has traditionally been based on height statistics but many modern estimates are based on wave energy. A simple empirical method is developed to relate statistical and energy based significant height estimates. The method is developed with CERC laboratory flume data from a 1:30 plane slope, two samples of field data, and stream function wave theory. Since the two significant height estimates differ by over 40% in some laboratory cases, engineers should clearly recognize the distinction between them.

Significant Wave Height for Shallow Water Design

Past efforts to estimate wind speeds over a large lake have met with very limited success. The purpose of this study is to demonstrate that, with a combined theoretical-empirical approach, winds over a lake can be obtained from transformed wind speeds at nearby land stations. The theoretical results provide a basis for comparison of many empirical data sets and establish a rational means of analyzing the expected differences between winds over land and those over a marine surface. This in turn affords a means of examining systematic variations in the ratio of wind speeds over a lake to wind speed over land. The good agreement between theory and observation indicates that wind estimates over the lake can be made for a wide range of synoptic conditions with an rms error of 5 knots. The theoretical curve for the lake wind/land wind ratio provides an estimate of lake winds well beyond wind speeds for which there are good empirical data.

Estimation of winds over the Great Lakes

Shoaling and decay of irregular wave trains with two distinct frequency peaks are simulated in a wave flume. The relative energy in each wave train, the closeness of the frequency peaks, and the total wave energy were varied over 12 cases. Wave-gauge measurements across the 1:30 plane slope in the flume show that linear superposition of single-peaked wave trains or lumping all energy into the dominant wave train are not satisfactory representations of multiple wave trains. The measurements also show that the wave train with the low-frequency peak dominates in the surf zone. Waves with the low-frequency peak appear unaffected by the second wave train, but the high-frequency wave train decays faster in the presence of the low-frequency waves. The variation of wave height through shoaling and breaking depends on the relative amount of energy in each of the wave trains and the closeness of the peak frequencies.

Charles L. Vincent

Papers

Refraction-diffraction of irregular waves over a mound

Wave Diffraction around Breakwater

Significant Wave Height for Shallow Water Design

Estimation of winds over the Great Lakes

Shoaling and Decay of Two Wave Trains on Beach