内部流体运动对波浪中沉井阻力的影响

摘要

In order to simulate the inner water flow and water exchange between the inside and the outside during the floating transportation of a caisson which is the result of the special structure of the caisson and some vertical cy-lindrical inner concavities, a simulation method has been developed. Based on the extended development of the general CFD software FLUENT, regular head wave series is numerically simulated and the resistance in the wave is computed with close attention paid to the effects of the inner fluid sloshing against the caisson resistance in the wave. The caisson resistances in 3 waves of different periods are computed with the unsteady VOF method, and the Fourier series analysis is performed to get 3 orders of harmonic amplitudes and phases. It has been discovered that the inner fluid sloshing can not be neglected, otherwise it can overcast the wave effects, and result in invalid com-putation of wave loads and caisson motions in waves.%针对沉井内部由于存在垂向柱状空腔这一特殊的结构形式而引起的在浮运过程中产生内部水流及内外水交换问题，基于对通用CFD软件FLUENT的二次开发，数值模拟了迎浪规则波中的沉井阻力，尤其对沉井内部流体的影响进行了研究。采用非定常VOF方法对沉井在具有不同周期的3个波浪上的阻力进行了计算，并对结果进行了傅里叶级数分析，得到了3阶谐振幅值和相位。研究表明沉井内部流体的影响不可忽略，它甚至会覆盖波浪的影响，使与波浪相关的载荷及相应的运动参数无法通过计算获得。