scholarly journals Influence of Bottom Friction on Sea Surface Roughness and Its Impact on Shallow Water Wind Wave Modeling

2000 ◽  
Vol 30 (7) ◽  
pp. 1743-1756 ◽  
Author(s):  
Hakeem K. Johnson ◽  
Henrik Kofoed-Hansen
Keyword(s):  
Surface Roughness ◽  
Shallow Water ◽  
Wind Wave ◽  
Bottom Friction ◽  
Sea Surface ◽  
Wave Modeling ◽  
Sea Surface Roughness

The Dependence of Signal Coherence on Sea-Surface Roughness for High and Low Duty Cycle Sonars in a Shallow-Water Channel

2017 ◽  
Vol 42 (2) ◽  
pp. 298-318 ◽  
Author(s):  
Paul C. Hines ◽  
Stefan M. Murphy ◽  
Douglas A. Abraham ◽  
Grant B. Deane
Keyword(s):  
Surface Roughness ◽  
Shallow Water ◽  
Duty Cycle ◽  
Water Channel ◽  
Sea Surface ◽  
Sea Surface Roughness ◽  
Low Duty Cycle

scholarly journals On the Wave State Dependence of the Sea Surface Roughness at Moderate Wind Speeds under Mixed Wave Conditions

2020 ◽  
Vol 50 (11) ◽  
pp. 3295-3307
Author(s):  
Shuiqing Li ◽  
Zhongshui Zou ◽  
Dongliang Zhao ◽  
Yijun Hou
Keyword(s):  
Surface Roughness ◽  
Wind Wave ◽  
Wind Waves ◽  
Sea Surface ◽  
Wave Steepness ◽  
Threshold Behavior ◽  
Wind Speeds ◽  
Dominant Wave ◽  
Sea Surface Roughness ◽  
Mixed Wave

AbstractWind stress depends on the sea surface roughness, which can be significantly changed by surface wind waves. Based on observations from a fixed platform, we examined the dependences of the sea surface roughness length on dominant wave characteristic parameters (wave age, wave steepness) at moderate wind speeds and under mixed-wave conditions. No obvious trend was found in the wave steepness dependence of sea surface roughness, but a wave steepness threshold behavior was readily identified in the wave age dependence of sea surface roughness. The influence of dominant wind waves on the surface roughness was illustrated using a wind–wave coupling model. The wave steepness threshold behavior is assumed to be related to the onset of dominant wave breaking. The important role of the interaction between swell and wind wave was highlighted, as swell can absorb energy from locally generated wind wave, which subsequently reduces the wave steepness and the probability of dominant wave breaking.

Dynamic modelling of sea-surface roughness for large-eddy simulation of wind over ocean wavefield

2013 ◽  
Vol 726 ◽  
pp. 62-99 ◽  
Author(s):  
Di Yang ◽  
Charles Meneveau ◽  
Lian Shen
Keyword(s):  
Surface Roughness ◽  
Large Eddy Simulation ◽  
Wind Wave ◽  
Dynamic Modelling ◽  
Sea Surface ◽  
Near Surface ◽  
Eddy Simulation ◽  
Sea Surface Roughness ◽  
Large Eddy ◽  
The Waves

AbstractWind blowing over the ocean surface can be treated as a turbulent boundary layer over a multiscale rough surface with moving roughness elements, the waves. Large-eddy simulation (LES) of such flows is challenging because LES resolves wind–wave interactions only down to the grid scale, $\Delta $, while the effects of subgrid-scale (SGS) waves on the wind need to be modelled. Usually, a surface-layer model based on the law of the wall is used; but the surface roughness has been known to depend on the local wind and wave conditions and is difficult to parameterize. In this study, a dynamic model for the SGS sea-surface roughness is developed, with the roughness corresponding to the SGS waves expressed as ${\alpha }_{w} \hspace{0.167em} { \sigma }_{\eta }^{\Delta } $. Here, ${ \sigma }_{\eta }^{\Delta } $ is the effective amplitude of the SGS waves, modelled as a weighted integral of the SGS wave spectrum based on the geometric and kinematic properties of the waves for which five candidate expressions are examined. Moreover, ${\alpha }_{w} $ is an unknown dimensionless model coefficient determined dynamically based on the first-principles constraint that the total surface drag force or average surface stress must be independent of the LES filter scale $\Delta $. The feasibility and consistency of the dynamic sea-surface roughness models are assessed by a priori tests using data from high-resolution LES with near-surface resolution, appropriately filtered. Also, these data are used for a posteriori tests of the dynamic sea-surface roughness models in LES with near-surface modelling. It is found that the dynamic modelling approach can successfully capture the effects of SGS waves on the wind turbulence without ad hoc prescription of the model parameter ${\alpha }_{w} $. Also, for ${ \sigma }_{\eta }^{\Delta } $, a model based on the kinematics of wind–wave relative motion achieves the best performance among the five candidate models.

Sign in / Sign up

Export Citation Format

Share Document