INTERACTIONS OF WAVES WITH IDEALIZED HIGH-RELIEF BOTTOM ROUGHNESS

  • Xiao Yu
  • Johanna H. Rosman
  • James L. Hench

Abstract

Interactions between waves and high-relief bottom roughness were investigated using Large Eddy Simulations of oscillatory flow over an infinite array of regularly spaced hemispheres. Simulation results were analyzed using a spatially- and phase-averaged momentum balance to provide insight into how flow-topography interactions affect wave-driven oscillating flows. Phase-averaging was applied first, and then spatial averaging was applied over volumes with horizontal length scales greater than the size of a single solid obstacle but fine enough in the vertical direction that the vertical structure of the dynamics was resolved. Spatial averaging of the momentum equation results in terms that represent drag and inertial forces, and a dispersive stress term that represents a vertical momentum flux induced by the spatial heterogeneity of the phase-averaged flow. These new terms require parameterization in coastal ocean wave and circulation models.

References

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Nielsen (1992): Coastal bottom boundary layers and sediment transport. World Scientific. Sleath (1986): Turbulent oscillatory flow over rough beds, J. Fluid Mech., 182, 369-409.

Mirfenderesk (2003): Direct measurements of the bottom friction factor beneath surface gravity waves. Applied Ocean Res., 25(5), 269-287.

Published
2018-12-30
How to Cite
Yu, X., Rosman, J. H., & Hench, J. L. (2018). INTERACTIONS OF WAVES WITH IDEALIZED HIGH-RELIEF BOTTOM ROUGHNESS. Coastal Engineering Proceedings, 1(36), waves.57. https://doi.org/10.9753/icce.v36.waves.57