Wave height

About: Wave height is a research topic. Over the lifetime, 5920 publications have been published within this topic receiving 100257 citations.

Wave variance partitioning in the trough of a barred beach

Abstract: The wave-induced velocity field in the nearshore is composed of contributions from incident wind waves (f > 0.05 Hz), surface infragravity waves (f 2/g), where fis the frequency,  = 2f, }c is the radial alongshore wavenumber (2re/L, L being the alongshore wavelength), [ is the beach slope, and g is the acceleration due to gravity. Using an alongshore array of current meters located in the trough of a nearshore bar (mean depth = 1.5 m), we investigate the bulk statistical behaviors of these wave bands over a wide range of incident wave conditions. The behavior of each contributing wave type is parameterized in terms of commonly measured or easily predicted variables describing the beach profile, wind waves, and current field. Over the 10-day period, the mean contributions (to the total variance) of the incident, infragravity, and shear wave bands were 71.5%, 14.3% and 13.6% for the alongshore component of flow (mean rms oscillations of 44, 20, and 19 cm s -1, respectively), and 81.9%, 10.9%, and 6.6% for the cross-shore component (mean rms oscillations of 92, 32, and 25 cm s -1, respectively). However, the values varied considerably. The contribution to the alongshore (cross-shore) component of flow ranged from 44.888.4% (58.5-95.8%) for the incident band, to 6.2-26.6% (2.5-32.4%) for the infragravity band, and 3.433.1% (0.6-14.3%) for the shear wave band. Incident wave oscillations were limited by depth-dependent saturation over the adjacent bar crest and varied only with the fide. The infragravity wave rms oscillations on this barred beach are best parameterized by the offshore wave height, consistent with previous studies on planar beaches. Comparison with data from four other beaches of widely differing geometries shows the shoreline infragravity amplitude to be a near-constant ratio of the offshore wave height. The magnitude of the ratio is found to be dependent on the Iribarren number, 0 = [(H/Lo) -1/2. Shear waves are, as previous observation and theory suggest (Oltman-Shay et al., 1989; Bowen and Holman, 1989), significantly correlated with a prediction of the seaward facing shear of the longshore current.

System and method for measuring wave directional spectrum and wave height

Abstract: A system and method for measuring the directional spectrum of one or more waves in a fluid medium using a multi-beam sonar system. In an exemplary embodiment, range cells located within a plurality of acoustic beams are sampled to provide current velocity data. Optionally, wave surface height and pressure data is obtained as well. This velocity, wave height, and pressure data is Fourier-transformed by one or more signal processors within the system, and a surface height spectrum produced. A cross-spectral coefficient matrix at each observed frequency is also generated from this data. A sensitivity vector specifically related to the ADCP's transducer array geometry is used in conjunction with maximum likelihood method (MLM), iterative maximum likelihood method (IMLM), or other similar methods to solve a the wave equation at each frequency and produce a frequency-specific wave directional spectrum. Ultimately, the frequency-specific spectra are combined to construct a complete two-dimensional wave directional spectrum. The system is also capable of measuring current profile as a function of depth in conjunction with wave direction and wave height.

Comparison of field observations of the vertical distribution of suspended sand and its prediction by models

Abstract: Models for the vertical distribution of suspended sediment under waves and currents are compared with field observations The models include a diffusion-based model, a convection-based model, and a combined convection-diffusion model The field observations were carried out at Vilano Beach, Florida, in a water depth of approximately 3 to 4 m, with a median grain diameter of 014 mm The rms wave height ranged from approximately 04 to 12 m Under low waves, the seabed was covered with very small ripples, and, under the higher waves, sheet flow conditions were present The diffusion-based model was found to best describe the observed data under high wave conditions, but the convection model was more accurate under low wave conditions Over all conditions, the combined model was the most accurate These results are consistent with the different mechanisms for mixing suspended sediment over flat versus rippled beds