Should we care about the spatial heterogeneity in coral reefs under unidirectional turbulent flows?

TL;DR

This study compares flow dynamics over different coral geometries and a stochastic coral bed, highlighting significant differences in hydrodynamic responses and emphasizing the importance of spatial heterogeneity in modeling coral reef flows.

Contribution

It provides a systematic analysis of flow over various coral geometries and introduces insights into how spatial heterogeneity affects hydrodynamic responses in coral reef modeling.

Findings

Significant differences between stochastic and regular coral beds in flow response.

Local effects are influenced by coral geometry and arrangement.

Results inform improved modeling of coral heterogeneity in ocean simulations.

Abstract

In this work, we systematically investigate the similarities and differences observed between a hydraulically rough wall comprised of an array of cylinders, massive corals, and branching corals arranged in a staggered manner, along with a stochastically generated coral bed using a scale-resolving computational framework. Our data suggests that for all the flow parameters of interest, there is a substantial difference observed between the stochastic coral bed and the regularly arranged coral bed. By analysing the double-averaged statistics and time-averaged spatial heterogeneity in the hydrodynamic response, we explain the differences observed between the four cases that bring out significant local effects. These observations have important consequences for modelling coral-like roughness in numerical and experimental settings to better understand the mean flow statistics and the spatial heterogeneity induced as a consequence of the underlying coral geometry. Our results can help inform the coastal ocean modelling efforts to further improve the inclusion of coral heterogeneity within two-equation closure models by further investigating the impact of spatially stochastic, rough bottom boundary layers.