scholarly journals Universal equilibrium range of turbulence

1984 ◽  
Vol 27 (9) ◽  
pp. 2229 ◽  
Author(s):  
J. Qian
Keyword(s):  
Equilibrium Range

Wave Breaking Dissipation in a Young Wind Sea

2014 ◽  
Vol 44 (1) ◽  
pp. 104-127 ◽  
Author(s):  
Michael Schwendeman ◽  
Jim Thomson ◽  
Johannes R. Gemmrich
Keyword(s):  
Wind Waves ◽  
Phase Speed ◽  
Field Studies ◽  
Turbulent Energy ◽  
Strength Parameter ◽  
Video Recordings ◽  
Sonar System ◽  
Wind Sea ◽  
Equilibrium Range

Abstract Coupled in situ and remote sensing measurements of young, strongly forced wind waves are applied to assess the role of breaking in an evolving wave field. In situ measurements of turbulent energy dissipation from wave-following Surface Wave Instrument Float with Tracking (SWIFT) drifters and a tethered acoustic Doppler sonar system are consistent with wave evolution and wind input (as estimated using the radiative transfer equation). The Phillips breaking crest distribution Λ(c) is calculated using stabilized shipboard video recordings and the Fourier-based method of Thomson and Jessup, with minor modifications. The resulting Λ(c) are unimodal distributions centered around half of the phase speed of the dominant waves, consistent with several recent studies. Breaking rates from Λ(c) increase with slope, similar to in situ dissipation. However, comparison of the breaking rate estimates from the shipboard video recordings with the SWIFT video recordings show that the breaking rate is likely underestimated in the shipboard video when wave conditions are calmer and breaking crests are small. The breaking strength parameter b is calculated by comparison of the fifth moment of Λ(c) with the measured dissipation rates. Neglecting recordings with inconsistent breaking rates, the resulting b data do not display any clear trends and are in the range of other reported values. The Λ(c) distributions are compared with the Phillips equilibrium range prediction and previous laboratory and field studies, leading to the identification of several inconsistencies.

scholarly journals THE PROBABILITY CHARACTERISTICS OP WAVES AND WAVE PRESSURES AT A VERTICAL BREAKWATER

1984 ◽  
Vol 1 (19) ◽  
pp. 50
Author(s):  
Huang Peiji ◽  
Zhao Binglai
Keyword(s):  
Probability Distribution ◽  
High Frequency ◽  
Pressure Field ◽  
Spectral Component ◽  
High Frequency Band ◽  
Wave Pressure ◽  
Spectral Components ◽  
Wave Heights ◽  
Vertical Breakwater ◽  
Equilibrium Range

In this paper, under the condition of waves in front of a breakwater being not broken, studies were made on the characterises of probability distribution of waves and wave pressures, the regularity of the spectral component attenuation with depth and the constitution of the high frequency band of wave pressure spectrum. The distributions of wave heights in front of a vertical breakwater, the range of wave pressure fluctuation at different subsurface levels, and the wave periods have shown that they are practically invariable with depth and can be determined theoretically. The spectral constitution of wave pressure field and the regularity of attenuation of spectral components were analyzed at the vertical breakwater, and a new expression describing the equilibrium range of wave pressure spectrum was obtained.

Breaking waves and the equilibrium range of wind-wave spectra

1997 ◽  
Vol 342 ◽  
pp. 377-401 ◽  
Author(s):  
S. E. BELCHER ◽  
J. C. VASSILICOS
Keyword(s):  
High Frequency ◽  
Wind Wave ◽  
Breaking Waves ◽  
Breaking Wave ◽  
Wave Spectra ◽  
Scale Invariant ◽  
Self Similar ◽  
Dynamical Properties ◽  
Dynamical Balance ◽  
Equilibrium Range

When scaled properly, the high-wavenumber and high-frequency parts of wind-wave spectra collapse onto universal curves. This collapse has been attributed to a dynamical balance and so these parts of the spectra have been called the equilibrium range. We develop a model for this equilibrium range based on kinematical and dynamical properties of breaking waves. Data suggest that breaking waves have high curvature at their crests, and they are modelled here as waves with discontinuous slope at their crests. Spectra are then dominated by these singularities in slope. The equilibrium range is assumed to be scale invariant, meaning that there is no privileged lengthscale. This assumption implies that: (i) the sharp-crested breaking waves have self-similar shapes, so that large breaking waves are magnified copies of the smaller breaking waves; and (ii) statistical properties of breaking waves, such as the average total length of breaking-wave fronts of a given scale, vary with the scale of the breaking waves as a power law, parameterized here with exponent D.

scholarly journals Waves and the equilibrium range at Ocean Weather Station P

2013 ◽  
Vol 118 (11) ◽  
pp. 5951-5962 ◽  
Author(s):  
J. Thomson ◽  
E. A. D'Asaro ◽  
M. F. Cronin ◽  
W. E. Rogers ◽  
R. R. Harcourt ◽  
...  
Keyword(s):  
Weather Station ◽  
Equilibrium Range

On Phillips' Theory of Equilibrium Range in the Spectra of Wind-Generated Gravity Waves

1975 ◽  
Vol 5 (3) ◽  
pp. 410-420 ◽  
Author(s):  
S. A. Kitaigordskii ◽  
V. P. Krasitskii ◽  
M. M. Zaslavskii
Keyword(s):  
Gravity Waves ◽  
Equilibrium Range

Wind action on water standing in a laboratory channel

1966 ◽  
Vol 26 (4) ◽  
pp. 651-687 ◽  
Author(s):  
G. M. Hidy ◽  
E. J. Plate
Keyword(s):  
Water Surface ◽  
Wind Waves ◽  
Pressure Fluctuations ◽  
Leading Edge ◽  
Wavy Surface ◽  
Recent Theory ◽  
Waves And Currents ◽  
Mean Wind Speed ◽  
Equilibrium Range ◽  
The Waves

The development of waves and currents resulting from the action of a steady wind on initially standing water has been investigated in a wind–water tunnel. The mean air flow near the water surface, the properties of wind waves, and the drift currents were measured as they evolved with increasing fetch, depth and mean wind speed. The results suggest how the stress on the water surface changes with an increasingly wavy surface, and, from a different viewpoint, how the drift current and the waves develop in relation to the friction velocity of the air. The amplitude spectra calculated for the wavy surface reflected certain features characteristic of an equilibrium configuration, especially in the higher frequencies. The observed equilibrium range in the high frequencies of the spectra fits the f−5 rule satisfactorily up to frequencies f of about 15 c/s. The wave spectra also revealed how the waves grow in the channel, both with time at a fixed point, and with distance from the leading edge of the water. These results are discussed in the light of recent theories for wave generation resulting from the action of pressure fluctuations in the air, and from shearing flow instabilities near the wavy surface. The experimental observations agree reasonably well with the predictions of the recent theory proposed by Miles, using growth rates calculated for the mechanism suggesting energy transfer to the water through the viscous layer in the air near the water surface.

scholarly journals A Model of the Air–Sea Momentum Flux and Breaking-Wave Distribution for Strongly Forced Wind Waves

2007 ◽  
Vol 37 (7) ◽  
pp. 1811-1828 ◽  
Author(s):  
Tobias Kukulka ◽  
Tetsu Hara ◽  
Stephen E. Belcher
Keyword(s):  
Momentum Flux ◽  
Breaking Waves ◽  
Wind Forcing ◽  
Small Scale ◽  
Breaking Wave ◽  
Unit Surface Area ◽  
Wave Age ◽  
Coupled Equations ◽  
Wave Distribution ◽  
Equilibrium Range

Abstract Under high-wind conditions, breaking surface waves likely play an important role in the air–sea momentum flux. A coupled wind–wave model is developed based on the assumption that in the equilibrium range of surface wave spectra the wind stress is dominated by the form drag of breaking waves. By conserving both momentum and energy in the air and also imposing the wave energy balance, coupled equations are derived governing the turbulent stress, wind speed, and the breaking-wave distribution (total breaking crest length per unit surface area as a function of wavenumber). It is assumed that smaller-scale breaking waves are sheltered from wind forcing if they are in airflow separation regions of longer breaking waves (spatial sheltering effect). Without this spatial sheltering, exact analytic solutions are obtained; with spatial sheltering asymptotic solutions for small- and large-scale breakers are derived. In both cases, the breaking-wave distribution approaches a constant value for large wavenumbers (small-scale breakers). For low wavenumbers, the breaking-wave distribution strongly depends on wind forcing. If the equilibrium range model is extended to the spectral peak, the model yields the normalized roughness length (Charnock coefficient) of growing seas, which increases with wave age and is roughly consistent with earlier laboratory observations. However, the model does not yield physical solutions beyond a critical wave age, implying that the wind input to the wave field cannot be dominated by breaking waves at all wavenumbers for developed seas (including field conditions).

Sign in / Sign up

Export Citation Format

Share Document