بخشی از مقاله (انگلیسی)
Vertical wall breakwater with inclined culvert (VWBIC) is a new-type environmentally friendly breakwater proposed in this paper, which is a further development of vertical wall breakwater with horizontal culvert (Lv and Zhao, 2021). To analyze the hydrodynamic performance of the VWBIC on a permeable rubble mound foundation and to propose the optimal structural parameters of the culvert for engineering application, an eigenfunction expansion boundary element method (EEBEM) is used. Besides, newly performed computational fluid dynamics (CFD) results are used to reveal the interaction mechanism between waves and the VWBIC. The results show that when the culvert inclined angle is positive, the VWBIC is more beneficial to engineering application. With an increase in the culvert inclined angle, the VWBIC can effectively reduce wave transmission coefficient of medium and long waves, promote the oscillatory flow of short waves and reduce the wave force on the VWBIC. Meanwhile, through the effects of wave shallowing, resonance and energy dissipation, the permeable rubble mound foundation can significantly reduce the wave reflection and wave force on the VWBIC. Finally, the optimal structural parameters of the VWBIC are obtained. All these indicate that the VWBIC is a more effective structure than vertical wall breakwater with horizontal culvert.
Breakwater with culvert (BC) is a kind of environmentally friendly breakwater for coastal and offshore engineering (Tsoukala and Moutzouris, 2009; Rageh and Koraim, 2010). Compared with the gravity breakwater, the BC can effectively reduce wave reflection and wave force on the breakwater (Li et al., 1997b), promote water exchange, and reduce the sediment deposition in the harbor basin (Lv and Zhao, 2021). Besides, some aquatic organisms can freely pass through the culvert, which is of great significance to maintaining the aquatic ecological environment in the harbor basin (Tsoukala et al., 2014). However, the distribution of sediment concentration in the ocean follows the law of being sparse at the top and dense at the bottom, especially for the encircled harbor basin. To further promote the water exchange and reduce sediment deposition, a new-type vertical wall breakwater with inclined culvert (VWBIC) is proposed in this paper, and it is a further study of vertical wall breakwater with horizontal culvert (Lv and Zhao, 2021). When the culvert inlet (sea area) is higher than the culvert outlet (harbor area), the high turbidity water at the bottom of the harbor will flow into the sea through oscillatory flow, and the low turbidity water at the surface of sea will flush the harbor area.
A new-type environmentally friendly breakwater named vertical wall breakwater with inclined culvert (VWBIC) is proposed in this paper. A coupled eigenfunction expansion boundary element method (EEBEM) combining computational fluid dynamics (CFD) numerical simulations is developed to study the hydrodynamic performance of the VWBIC on a permeable rubble mound foundation. Results show that compared with vertical wall breakwater with horizontal culvert, the VWBIC can optimize the hydrodynamic performance better, which has great engineering significance. From this study, the following conclusions can be drawn:
1. When the culvert inclined angle 𝜃 is opposite, such as 𝜃 and −𝜃, both the amplitude of the transmission wave and reflection wave are the same. But the oscillatory flow with positive inclined angle (+𝜃) is obviously larger than that with negative inclined angle (−𝜃), and with the increase of 𝜃 and relative water depth 𝑘ℎ, this difference is more obvious.