涌潮冲击排桩式丁坝的数值模拟

Numerical simulation of bore against sheet-pile groin

为了研究钱塘江排桩式丁坝在涌潮作用下的受力机理,对涌潮冲击排桩式丁坝进行了数值模拟,采用标准κ-ε紊流模型和体积函数法(VOF)追踪自由水面的方法,得出了丁坝附近的流场分布和自由水面的位置,揭示了丁坝上的涌潮压力在时间和空间上的变化规律:(1)当涌潮冲击丁坝时,涌潮压力急剧增大,约2 s后涌潮压力达到最大值,之后,有一段下降的过程,随后出现较小幅度的振荡,最后涌潮压力趋于稳定,并且在垂直方向上各高程处的涌潮压力最大值基本出现在同一时刻;2)在潮前水位以上丁坝上的涌潮压力呈梯形分布,而在潮前水位以下丁坝上的涌潮压力随深度基本保持不变,呈矩形分布.

Numerical simulation of bore against sheet-pile groin was carried out to study the stress characteristic of sheet-pile groin under the impact of bore. By using standard turbulence model and volume of fluid （VOF） method, flow fields and the position of free surface were obtained and the rule of time history and the space distribution of bore pressure on the sheet-pile groin was revealed. 1） Bore pressure on the sheet-pile groin rises rapidly when tidal bore impacts sheet-pile groin. The duration of rise is about 2 s, and then bore pressure of groin begins to fall for about 1 s. Finally bore pressure drives steady stage with fluctuation within a narrow range. The peak values of bore pressure on sheet-pile groin at different heights occur almost at the same time. 2） The maximum bore pressure on sheet-pile groin occurs at still water line. The vertical distribution of bore pressure on sheet-pile groin is linear above the still water line and approximately rectangular below the still water line.