不同湍流模式下钱塘江涌潮水流三维模拟

Three-dimensional simulation of tidal bore in the Qiantang estuary under different turbulence models

钱塘江涌潮具有动力作用强和流速变化快等特点。涌潮水流紊动复杂,流速的垂向分布和紊动强度息息相关。通过涌潮水流实测资料的分析可以发现,涌潮作用下流速垂向分布在底部和上层存在差异。为研究涌潮作用下流速垂向分布的特征,应用基于非结构网格下有限体积法模型FVCOM对钱塘江涌潮河段水流运动进行三维数值模拟。考虑到涌潮紊动作用复杂且对流速的垂向分布起着重要影响,采用不同的湍流模式对涌潮传播过程中水流的运动特征开展研究。通过与涌潮河段实测资料的验证,复演涌潮到达前后水流运动特征,给出涌潮水流湍动能的变化过程。研究成果有助于深入认识涌潮水流紊动特征和流速的分布规律,为涌潮作用下物质输运的研究提供基础。

The tidal bore in the Qiantang estuary has the characteristics of intense hydrodynamics and rapid-variation velocity.The turbulence of tidal bores is complicated,and turbulence intensity is closely relevant to the vertical distribution of velocity.It is found that the distribution of the velocity along the water depth is different at the bottom and the top layers under the tidal bore by the analysis of the field data.This study is to simulate the three-dimensional feature of the tidal bore in the Qiantang estuary based on the unstructured grids finite-volume method FVCOM model so as to investigate the distribution of velocity along the water depth.As the turbulence of the tidal bore is complicated and it plays an important role in the distribution of velocity,the tidal flows are studied during the propagation of tidal bores by different turbulence models.The movement of the flow is reproduced before and after the arrival of tidal bores by the calibration with the measured data,the time-varying process of turbulent kinetic energy is exhibited.The present results are helpful to deepen the understanding of turbulence characteristics and the distribution of velocity,and it will provide a basis for the study of mass transport.