Simulation for 2D Flows and Water Quality in Curvilinear Coordinates

This paper presents a numerical method to simulate the 2D tidal flow and water quality under the orthogonal curvilinear coordinates. In order to overcome the computational difficulties in natural rivers, such as the complicated boundary figures, the great disparity between length and width of computational domain, etc., orthogonal boundary-fitted grid is used, the irregular domain in physical plane is transformed into a rectangular domain in transformed plane, and the depth averaged momentum equations and mass equation are rewritten and discretized based on the alternating direction implicit finite difference scheme in curvilinear coordinates. Practical application of the method is illustrated by an example for the Yangtze River in the vicinity of Nanjing city. A fair agreement between the values measured and computed demonstrates the validity of the method developed.