Hydrodynamics of in-canopy flow in synthetically generated coral reefs under oscillatory wave motion

Abstract

The interaction of oscillatory wave motion with morphologically complex coral reefs showcases a wide range of consequential hydrodynamic responses within the canopy. While a large body of literature has explored the interaction of morphologically simple coral reefs, the in-canopy flow dynamics in complex coral reefs are poorly understood. This study used a synthetically generated coral reef over flat topography with varying reef height and frontal and planform density to understand the in-canopy turbulence dynamics. Using a turbulence-resolving computational framework, we found that most of the turbulent kinetic energy dissipation is confined to a region below the top of the reef and above the Stokes boundary layer. The results also suggest that most of the vertical Reynolds stress peaks within this region positively contribute to the down-gradient momentum flux during the wave cycle. These findings shed light on the physical relationships between in-canopy flow and morphologically complex coral reefs, thereby motivating a further need to explore the hydrodynamics of such flows using a scale-resolving computational framework.