感潮河段平面二维非恒定水流模型深化研究

建立了基于非结构网格的感潮河段平面二维非恒定流模型,探讨了时间步长和非结构网格无序性对计算误差的影响,并和结构网格上的研究成果进行了对比。计算结果表明:(1)当采用隐式算法求解非恒定流时,时间步长会对流速和水位计算结果产生影响,当时间步长小于一定值时,计算所得的水位过程和流速分布才和实测值比较吻合,当时间步长增加时计算值与实测值之间误差将逐渐增加;(2)时间步长较小时,网格布置的无序性不会对非恒定流模拟产生明显不利的影响,但是随着时间步长的增加非结构网格的无序性会导致计算误差快速增加。

Deepened study on two-dimensional unsteady flow model for tidal river reach

An unstructured grid-based two-dimensional unsteady flow model for tidal river reach is established，and then the impacts from the time step and disorder of the unstructured grid on the calculation error are discussed and compared with those from the result of the study made on the structured grid. The calculation result shows that（1）when the unsteady flow is solved with implicit algorithm，the calculations of both the flow velocity and water level are to be impacted by time step； only when the time step is less than a certain value，the calculated water level process and flow velocity distribution can be coincided with the measured values； when time step is increased，the error between the calculated value and the measured one are to be gradually increased as well；（2）when the time step is less，no any obvious and unfavorable impacts are to be there from the disorder of the grid layout on the simulation of unsteady flow，however，the quick increase of the calculation error is to be caused by the disorder of the unstructured grid along with the increase of time step.