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

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.