NUMERICAL INVESTIGATIONS OF THE MECHANISMS ASSOCIATED WITH THE ONSHORE RIPPLE MIGRATION

  • Zhen Cheng
  • Peter Traykovski

Abstract

Quantification of cross-shore sediment transport is one of most intriguing challenges in shoreline and coastal geomorphology. During the past decades, several key mechanisms associated with onshore/offshore sediment transport have been identified, such as wave skewness/asymmetry, progressive wave streaming and undertow current. However, applying these mechanisms to the migration of wave formed bedforms (ripples) is not straightforward. For example, recent field observations off Fire Island, NY showed that ripples migrated onshore even during periods of offshore directed wave skewness, which is contradictory to the prediction of empirical sediment transport formulations. The physical processes driving ripple vortex formation, ejection and boundary layer streaming associated with rippled bed can further complicate the bedload/suspended load sediment transport over ripples. To fully understand these mechanisms, a comprehensive model that can resolve the ripple dynamics and interactions between free surface wave and rippled bed is examined.

References

Jacobsen, Fuhrman, Fredsøe (2011), A wave generation toolbox for the open-source CFD library: OpenFoamⓇ, Int. J. Numer. Methods Fluids, 70(9), 1073-1088.

B. Aupoix. (2015): Roughness corrections for the 𑘠− 𜔠shear stress transport model: Status and proposals. J. Fluids Eng., 137(2):021202.

F. R. Menter (1994): Two-equation eddy-viscosity turbulence models for engineering applications. AIAA journal, 32(8):1598-1605.

Published
2018-12-30
How to Cite
Cheng, Z., & Traykovski, P. (2018). NUMERICAL INVESTIGATIONS OF THE MECHANISMS ASSOCIATED WITH THE ONSHORE RIPPLE MIGRATION. Coastal Engineering Proceedings, 1(36), sediment.28. https://doi.org/10.9753/icce.v36.sediment.28