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High quality laboratory measurements of nearshore waves and morphology change at, or near prototype-scale are essential to support new understanding of coastal processes and enable the development and validation of predictive models. The DynaRev experiment was completed at the GWK large wave flume over 8 weeks during 2017 to investigate the response of a sandy beach to water level rise and varying wave conditions with and without a dynamic cobble berm revetment, as well as the resilience of the revetment itself. A large array of instrumentation was used throughout the experiment to capture: (1) wave transformation from intermediate water depths to the runup limit at high spatio-temporal resolution, (2) beach profile change including wave-by-wave changes in the swash zone, (3) detailed hydro and morphodynamic measurements around a developing and a translating sandbar. Measurement(s) surf zone waves • swash hydrodynamics • surf zone flow velocity • morphology • sediment Technology Type(s) Gauge or Meter Device • Lidar • velocimetry • mechanical profiler • optical backscatter sensor • Pressure transducers Factor Type(s) Wave height • Wave period • beach morphology Sample Characteristic - Environment beach • shingle beach Machine-accessible metadata file describing the reported data: https://doi.org/10.6084/m9.figshare.13194872 [ABSTRACT FROM AUTHOR]

A similarity parameter is derived to describe surf zone dissipation using the classical energy dissipation model for surf zone bores. This parameter can also be interpreted as a relative beach slope parameter, βγ, and, for shallow water sinusoidal waves, is the ratio of the local beach slope and the local wave steepness (H/L). βγ = 1 defines the boundary between two different energy dissipation regimes. Conditions with βγ<1 represent over-dissipative conditions, where the classical bore dissipation model provides more dissipation than that required for depth-limited waves (constant H/h) to be maintained. Conditions with βγ>1 represent under-dissipative conditions, where the bore model provides insufficient dissipation for depth-limited conditions to occur. Conditions with βγ = 1 at the breakpoint lead to locally saturated but not depth-limited surf. Hence, the new similarity parameter distinguishes between saturated and unsaturated surf conditions. Based on this bore dissipation model, an analytical model for the wave height transformation of monochromatic waves on planar beaches is derived. The cross-shore variation in wave height obtained from this model show different functional forms; concave upward for over-dissipative conditions and convex upward for under-dissipative conditions. Further, the analytical model shows that depth-limited conditions within the inner surf zone are not possible with this bore dissipation model and the model assumptions. Additional work is required to determine if this parameter is a useful predictor of other surf zone characteristics. Highlights: We derive a similarity parameter to describe surf zone dissipation. The similarity parameter defines the boundary of two dissipation regimes. The parameter distinguishes between saturated and unsaturated surf conditions. The classical bore dissipation model cannot predict depth-limited wave heights on a plane beach. [ABSTRACT FROM AUTHOR]

Abstract: The observed И-shape of the long wave generated by a single short wave pulse is explained qualitatively by including the free waves which are generated along with the well known bowl-shaped forced wave. Free waves of complicated shapes are generally formed as the wave group encounters gradual depth changes. However, the main qualitative feature, which has so far lacked a simple explanation, namely the long wave being И-shaped rather than a single bowl, can be explained through the simple free wave configuration which results from an abrupt onset of forcing at constant depth. И-shaped transient stages then occur between the initial flat surface and the final stage where free and forced waves have become completely separated from the forcing due to their different speeds. The И-shape is however also the shape of the gradually growing, resonant long wave due to a single short wave pulse, which travels with phase speed c and group velocity c g close to the long wave speed . The latter result is derived and compared with detailed laboratory experiments. It may explain the lack of observed H 2-dependence observed for some incident long waves, as well as the qualitative shapes of the long wave and of the cross correlation function between short wave envelope and long wave elevation. [Copyright &y& Elsevier]

In the swash zone, an assessment of swash flow properties requires an understanding of swash depth and swash velocity, which can affect sediment movement, as well as the design of coastal structures. The method of characteristics provides a useful tool to model unsteady shallow water flows, such as dam-break flow, swash flow and tsunami run-up. In this paper, bottom resistance was incorporated into the nonlinear shallow water equations to extend the application of the method of characteristics to account for frictional effects in the swash zone. The new characteristic equations are solved by the specified time interval scheme. The bottom resistance has little influence on the seaward swash hydrodynamics (initial swash stage), e.g., water depth and flow velocity, while its influence becomes significant in the small water depth region near the swash front, which reduces the maximum run-up height. At a specified time and location, and comparing with a frictionless swash solution, the uprush flow velocity reduces due to the bottom resistance, while the flow velocity increases during the initial phase of the backwash owing to the earlier reversal time with the bottom resistance. However, the differences with the inviscid solution are small within the swash lens. Conversely, the maximum backwash velocity is reduced significantly as a result of the shorter duration of the backwash. Consistent with previous field observations, friction does not significantly alter the gradient of the water surface elevation and a seaward-dipping water surface elevation is observed during the majority of the swash process. The dominant effect of bottom resistance is to reduce the range of inundation, particularly with larger resistance coefficients. The incorporation of the bottom resistance extends the application of method of characteristics in the swash zone to more practical problems, particularly where run-up elevation is critically important, e.g. overtopping flows. [ABSTRACT FROM AUTHOR]