Numerical investigation on hydrodynamic performance of an innovative aeration device with an array of wave-driven heaving buoys

Abstract

In the recent decades, the occurrence of hypoxia in coastal bottom waters has had adverse influences on the ecological system and fishery production. Therefore, to address this, an innovative aeration device with an array of four wave-driven heaving buoys was proposed in this study to produce bubbles and supply oxygen into the bottom seawater. A series of laboratory experiments were conducted to investigate the hydrodynamic performance of the device in regular waves, and a relatively simple 3-D computational fluid dynamics (CFD) numerical model was used to simulate the motion response of the array of four heaving buoys. The results indicate that the average heaving amplitude (AHA) and the capture width ratio (CWR) of the seaside buoy are higher than those of the lee-side buoy. Specifically, with increasing incident wave height, AHA increases but CWR decreases. Both AHA and CWR decrease with the increments in incident wave steepness, relative height and density of buoy and relative equivalent damping coefficient. Furthermore, the prediction formulas were calculated to assess the AHA of the seaside and lee-side buoys with a relatively high accuracy. The results obtained are significant for the optimal design and operation of the proposed innovative aeration device.