1. Measurements and Modeling of Pore‐Pressure Gradients in the Swash Zone Under Large‐Scale Laboratory Bichromatic Waves.
- Author
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Kranenborg, J. W. M., Pauli, T., Jacobsen, N. G., van der Werf, J. J., Dionisio Antonio, S., Campmans, G. H. P., Reniers, A. J. H. M., and Hulscher, S. J. M. H.
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PORE water pressure ,SEDIMENT transport ,PHYSICAL measurements ,PHYSICS laboratories - Abstract
The present work presents physical laboratory measurements of surface elevation and pore water pressures in a fine sand bed under bichromatic waves in a large‐scale laboratory experiment. This was done at three cross‐shore locations in the swash zone, with pressures being measured at different depths in the bed. The measurements show that the pore pressure signal decays and shifts with increased depth. These measurements are used to validate a practical model, based on the theory of Yamamoto et al. (1978, https://doi.org/10.1017/S0022112078003006) and Guest and Hay (2017, https://doi.org/10.1002/2016JC012257). The model corresponds well with the measurements (nRMSE < 0.2 and R2 > 0.95 for most probes) and shows that a frequency‐based model can reproduce the pressures in the bed, despite the bed being exposed during dry periods. Furthermore, the model provides the opportunity to calculate pressure gradients, both throughout the bed and at the bed surface. These modeled pressure gradients at the bed surface show that the vertical pressure gradient can have an important impact on the Shields parameter, thereby influencing sediment transport. Plain Language Summary: When waves run up and down the beach they can influence the pressure in the sand. In this work, we have measured pressures in the beach at different depths. A difference in pressure at different depths can lead to forces on the sand particles which make it easier or harder for the sand to move. The results show that at deep locations, the pressure varies slowly and a little later compared with pressures close to the beach surface. We also calculated the pressures with a model, which could predict the measured pressures very well. The model also shows that large differences in pressure exist at the bed surface. Key Points: New field‐scale laboratory measurements of pore pressures in the swash zone in a fine sand bed have been conductedAn analytical model based on Fourier decomposition models the pore pressures and gradients wellThe vertical pressure gradient can have an important impact on the Shields parameter, thereby influencing sediment transport [ABSTRACT FROM AUTHOR]
- Published
- 2023
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