Research On 2D Numerical Simulation Of Flow With Complex Boundaries In Orthonormal Curvilinear Coordinates

Numerical simulation is one of effective tools for studying water flow, and there are still many difficulties in numerical study of water flow for turbulence and complicated boundary conditions. In the paper, numerical studies of two-dimensional plane flow in orthonormal curvilinear coordinates and two-dimensional vertical flow and suspended sediment movement in σ coordinates have been conducted.In the numerical studies of two-dimensional plane flow, a method for generating body-fitted grid intersecting orthogonally boundaries has been described for the complicated boundary conditions in this paper. The Laplace equation has been applied to get two-dimensional orthonormal curvilinear grids inside the computational domain, and the subsection Lagrange interpolation boundary slide method of orthogonalized boundary for orthonormal curvilinear grid has been put forward and used on computational domain boundaries in the paper. The two-dimensional plane k-e turbulent model in curvilinear coordinates has been applied to study the flow for complicated boundary conditions. A physical model (1:100) of a section of Yangtze River near the Chongqing city has been used to study and validate the numerical model, and good agreements have been made among the numerical model results and the measured data and the results calculated by the FLOW3D software, which also shows that the numerical model used in the paper can be used to study flow in natural sinuous rivers.In the numerical studies of two-dimensional vertical flow and suspended sediment movement, the σ coordinates transformation has been made for the complicated topography, and the complicated curved boundaries have been transformed to regular rectangle boundaries, and the two-dimensional vertical suspended sediment movement model in σ coordinates have been built based on two-dimensional vertical k-ε turbulent model. Free surface model, two-dimensional vertical flow model and suspended sediment movement model have been calculated simultaneously with SIMPLE algorithm method. A physical model with 1:3 slope has been used to validate the two-dimensional vertical flow and suspended sedimentmovement models in the paper, and good agreements have been made between the numerical results and the measured results.