Wind-induced changes to shoaling surface gravity wave shape

Zdyrski, Thomas; Feddersen, Falk

doi:10.1103/physrevfluids.7.074802

Cited by 4 publications

(2 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In particular, for very mild but strong nonlinearity (Miles 1979), for small and weak nonlinearity (Green's law), and for steep and finite nonlinearity (Knowles & Yeh 2018). Cross-wave wind also has an integral effect on wave shape during shoaling (Zdyrski & Feddersen 2022). Therefore, this local parameter can only represent in bulk the integrated effects of wave shoaling, and is unlikely to be a good metric across a range of bathymetries and incident wave conditions.…”

Section: Discussionmentioning

confidence: 99%

“…Zdyrski & Feddersen (2022) derived a variable coefficient KdV-Burgers equation for a wind-forced soliton shoaling on a planar slope using the Jeffreys (1925) mechanism. Solving this equation numerically, wind direction and speed changed the polarity and magnitude of the induced bound dispersive tail, resulting in wave-shape changes focused on the rear wave face (Zdyrski & Feddersen 2022), qualitatively consistent with Feddersen & Veron (2005). However, this study was limited to shoaling well before wave overturning due to the asymptotic limits of the derivation.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Cross-shore wind-induced changes to field-scale overturning wave shape

et al. 2023

Self Cite

View full text Add to dashboard Cite

The shape of depth-limited breaking-wave overturns is important for turbulence injection, bubble entrainment and sediment suspension. Overturning wave shape depends on a nonlinearity parameter $H/h$ , where $H$ is the wave height, and $h$ is the water depth. Cross-shore wind direction (offshore/onshore) and magnitude affect laboratory shoaling wave shape and breakpoint location $X_{{bp}}$ , but wind effects on overturning wave shape are largely unstudied. We perform field-scale experiments at the Surf Ranch wave basin with fixed bathymetry and $\approx 2.25$ m shoaling solitons with small height variations propagating at $C=6.7\ \mathrm {m}\ \mathrm {s}^{-1}$ . Observed non-dimensional cross-wave wind $U_w$ was onshore and offshore, varying realistically ( $-1.2 < U_{w}/C < 0.7$ ). Georectified images, a wave staff, and lidar are used to estimate $X_{{bp}}$ , $H/h$ , overturn area $A$ and aspect ratio for 22 waves. The non-dimensionalized $X_{{bp}}$ was inversely related to $U_{w}/C$ . The non-dimensional overturn area and aspect ratio also were inversely related to $U_{w}/C$ , with smaller and narrower overturns for increasing onshore wind. No overturning shape dependence on the weakly varying $H/h$ was seen. The overturning shape variation was as large as prior laboratory experiments with strong $H/h$ variations without wind. An idealized potential air flow simulation on steep shoaling soliton shape has strong surface pressure variations, potentially inducing overturning shape changes. Through wave-overturning impacts on turbulence and sediment suspension, coastal wind variations could be relevant for near-shore morphology.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cross-shore wind-induced changes to field-scale overturning wave shape

et al. 2023

Self Cite

View full text Add to dashboard Cite

show abstract

Comparison of different discontinuous Galerkin methods based on various reformulations for gKdV equation: Soliton dynamics and blowup

Hong,

Wei,

Zhao

2024

Computer Physics Communications

View full text Add to dashboard Cite

Modelling wind-induced changes to overturning wave shape

Feddersen,

Hanson,

Mostert

et al. 2024

J. Fluid Mech.

View full text Add to dashboard Cite

Depth-limited overturning wave shape affects water turbulence and sediment suspension. Experiments have shown that wind affects shoaling and overturning wave shape, with uncertain mechanism. Here, we study wind effects (given by the wind Reynolds number) on solitary wave shoaling and overturning with the two-phase direct numerical simulations model Basilisk run in two dimensions on steep bathymetry for fixed wave Reynolds number and Bond number. For all wind, the propagating solitary wave sheds a two-dimensional turbulent air wake and has nearly uniform speed with minimal wave energy changes over the rapidly varying bathymetry. Wave-face slope is influenced by wind, and shoaling wave shape changes are consistent with previous studies. As overturning jet impacts, wind-dependent differences in overturn shape are quantified. The non-dimensional breakpoint location and overturn area have similar wind dependence as previous experience, whereas the overturn aspect ratio has opposite wind dependence. During shoaling, the surface viscous stresses are negligible relative to pressure. Surface tension effects are also small but grow rapidly near overturning. In a wave frame of reference, surface pressure is low in the lee and contributes 2–5 % to the velocity potential rate of change in the surface dynamic boundary condition, which, integrated over time, changes the wave shape. Reasons why the overturn aspect ratio is different than in experiment and why a stronger simulated wind is required are explored. The dramatic wind effects on overturning jet area, and thus to the available overturn potential energy, make concrete the implications of wind-induced changes to wave shape.

show abstract

Wind-induced changes to shoaling surface gravity wave shape

Cited by 4 publications

References 58 publications

Cross-shore wind-induced changes to field-scale overturning wave shape

Cross-shore wind-induced changes to field-scale overturning wave shape

Comparison of different discontinuous Galerkin methods based on various reformulations for gKdV equation: Soliton dynamics and blowup

Modelling wind-induced changes to overturning wave shape

Contact Info

Product

Resources

About