Simulations of scalar transport in oscillatory flow over a wavy wall

Abstract

A three-dimensional model that couples Reynolds–averaged Navier–Stokes equations with an advection–diffusion solver for flow and concentration fields over a fixed, non-permeable boundary is presented. The model simulates oscillatory flow over a wavy wall with a constant scalar source to assess the effects of a boundary-induced pressure gradient on passive scalar mixing. Results were compared to experimental data collected in an oscillating tray facility. Hydrodynamic quantities are in favourable agreement with observations. The model captured vortex dynamics correctly, and turbulence statistics were modelled reasonably well. Comparisons of time-resolved and bulk scalar quantities for crest and trough sources were in favourable agreement with observations. Results indicate that the model can be utilized to study processes with highly intermittent phenomena, such as the transport of wastes and dissolved nutrients in the coastal bottom.

Keywords:

• 3D model
• fixed bed
• RANS
• scalar transport
• wavy walls
• wave-induced flows

Acknowledgments

The authors are grateful to the Coastal Boundary Layers Lab research group at the University of Puerto Rico Mayagüez Campus for their help in providing the experimental results used in this study. Special thanks to Dr Umberto Ciri, for sharing his insight and access to the University of Texas TACC clusters, which were crucial to this work. The authors also kindly acknowledge Juan Vargas–Martínez and Dr. Gustavo Gutierrez for their help and insights.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the NSF under OCE-1753158.