A study of wave-driven flow characteristics across a reef under the effect of tidal current

An Investigation of Wave-Driven Current Characteristics across Fringing Reefs under Monochromatic Waves

“…The reef flat was elevated to 0.35 m above the flume bottom, and its alongshore width matched the flume width. The above experimental setup is identical to that of Yao et al [4], who investigated a barrier reef profile. However, we removed the pipe connecting the lagoon and the offshore side of the flume used to simulate a rip channel, as Yao et al did [4].…”

“…The above experimental setup is identical to that of Yao et al [4], who investigated a barrier reef profile. However, we removed the pipe connecting the lagoon and the offshore side of the flume used to simulate a rip channel, as Yao et al did [4]. This is because, for a fringing reef configuration, as we focus on in this study, the lagoon should be closed.…”

“…For an idealized fringing reef with no lateral reef flat rip channels, the shoreward wave-driven current can only be balanced by an undertow [2,3]. A better interpretation of the flow characteristics across the reef is vital to further understanding ecological (it transports nutrients, thus determining coral growth), biological (it conveys coral larval, thus maintaining coral breeding), and geomorphological (it moves sediments, thus affecting coral health) processes [4]; hence, it is beneficial to reef conservation projects.…”

“…They found a 2DV circulation consisting of a wave-driven forward current and an underneath return flow (undertow) in the surf zone near the reef edge. Subsequently, Yao et al [4] measured the vertical distribution of a wave-driven flow for a barrier reef configuration by considering the presence of a tidal current. They reported that the cross-reef mean current in the surf zone was primarily onshore-directed for the barrier reef case; a larger seaward/shoreward current below the wave trough could be observed as waves traveled on the ebb/flooding tidal current.…”

“…Yao et al [3] combined the RANS model with a k-ω SST turbulence closure that corrects for buoyancy production [24] to evaluate the cross-reef distributions of mean current and radiation stress through a fringing surf zone. More recently, Yao et al [4] employed the RANS equations incorporated with a modified k-ω SST turbulence model with enhanced stability in wave modeling [25] to investigate the cross-reef variations in mean flow, turbulent kinetic energy (TKE), and Reynolds shear stress along a barrier reef profile in the presence/absence of tidal currents. Nevertheless, such a stabilized turbulence model has not yet been used to investigate the wave-driven current over a fringing reef profile.…”