钦州湾滩槽地貌体系演化数值模拟研究*

钦州湾的滩槽地貌体系由东、中、西3条主要的涨、落潮水道和相间分布的沙脊(洲)组成。利用3D、无结构网格、有限体积法、并行计算的FVCOM数值模式对整个钦州湾水下地形的冲淤演变进行模拟研究。结果表明,槽冲滩淤的冲淤格局反映出潮流是塑造和维持钦州湾滩槽地貌体系演变的主导动力;钦州港对东水道2000年9月—2002年12月、2004年2月—2008年12月分别进行的3万吨级、10万吨级航道疏浚工程引起了目前的滩槽地貌体系的冲淤调整,初期强度较大,随后缓慢下降,这一调整过程将持续很长一段时间;各类工程的影响相互叠加,须密切关注。

Numerical modeling morphodynamics of channel-shoal system in Qinzhou bay

The channel-shoal system in Qinzhou bay consists of east, middle, west three major tidal channels and interpolating sand shoals (ridges). Numerical modeling of the morphodynamics of the channel-shoal system is performed using 3D unstructured grid, finite volume, paralleled computation FVCOM. Erosions occur within channels and depositions occur on shoals and at the end of channels, reflecting that tidal flow is really the dominant force to maintain and modify the channel-shoal system; two large-scale dredgings at the east channel during Sep. 2000 and Dec. 2012, and Feb. 2004 and Dec. 2008 respectively have caused the present sea bed erosion & deposition adjustment in the whole Qinzhou bay, the magnitudes of which are large initially but decreasing steadily;this adjustment process will last over 100 years if no further coastal engineering project is conducted and other presumed conditions are maintained. The morphological adjustments caused by various constructed and planned engineering projects might reinforce each other. This needs further comprehensive modeling study.