A two-dimensional （2D） dam-break flow numerical model was developed based on the finite-volume total variation diminishing （TVD） and monotone upstream-centered scheme for conservation laws （MUSCL）-Hancock scheme...A two-dimensional （2D） dam-break flow numerical model was developed based on the finite-volume total variation diminishing （TVD） and monotone upstream-centered scheme for conservation laws （MUSCL）-Hancock scheme, which has second-order accuracy in both time and space. A Harten-Lax-van Leer-contact （HLLC） approximate Riemann solver was used to evaluate fluxes. The TVD MUSCL-Hancock numerical scheme utilizes slope limiters, such as the minmod, double minmod, superbee, van Albada, and van Leer limiters, to prevent spurious oscillations and maintain monotonicity near discontinuities. A comparative study of the impact of various slope limiters on the accuracy of the numerical flow model was conducted with several dam-break examples including wet and dry bed cases. The numerical results of the superbee and double minmod limiters agree better with the theoretical solution and have higher accuracy than other limiters in one-dimensional （1D） space. The ratio of the downstream water depth to the upstream water depth was used to select the proper slope limiter. For the 2D numerical model, the superbee limiter should not be used, owing to significant numerical dispersion.展开更多
Flows in open-channel with partial emergent rigid vegetation cover are simulated using the lattice Boltzmann method (LBM) described by the 2-D nonlinear shallow water equations. The effect of vegetation is represented...Flows in open-channel with partial emergent rigid vegetation cover are simulated using the lattice Boltzmann method (LBM) described by the 2-D nonlinear shallow water equations. The effect of vegetation is represented with the vegetation roughness coefficient, which is related to the vegetation density, diameter of the vegetation elements and drag coefficient. The model is verified by three numerical tests: flow in a 180° curved open channel with partial vegetation cover at the outer bank, flow in a rectangular channel with a finite patch of vegetation and flow in a rectangular channel with a vegetated bank. Numerical results are compared with the experimental data, and the good agreement proved that the presented model can model the vegetated channel flows correctly.展开更多
基金supported by the National Natural Science Foundation of China(Grants No.51679170,51379157,and 51439007)
文摘A two-dimensional （2D） dam-break flow numerical model was developed based on the finite-volume total variation diminishing （TVD） and monotone upstream-centered scheme for conservation laws （MUSCL）-Hancock scheme, which has second-order accuracy in both time and space. A Harten-Lax-van Leer-contact （HLLC） approximate Riemann solver was used to evaluate fluxes. The TVD MUSCL-Hancock numerical scheme utilizes slope limiters, such as the minmod, double minmod, superbee, van Albada, and van Leer limiters, to prevent spurious oscillations and maintain monotonicity near discontinuities. A comparative study of the impact of various slope limiters on the accuracy of the numerical flow model was conducted with several dam-break examples including wet and dry bed cases. The numerical results of the superbee and double minmod limiters agree better with the theoretical solution and have higher accuracy than other limiters in one-dimensional （1D） space. The ratio of the downstream water depth to the upstream water depth was used to select the proper slope limiter. For the 2D numerical model, the superbee limiter should not be used, owing to significant numerical dispersion.
基金Project supported by the CRSRI Open Research Program (Grant No. CKWV2017501/KY)the National Nature Science Foundation of China (Grant Nos. 51679170, 51879199 and 51439007).
文摘Flows in open-channel with partial emergent rigid vegetation cover are simulated using the lattice Boltzmann method (LBM) described by the 2-D nonlinear shallow water equations. The effect of vegetation is represented with the vegetation roughness coefficient, which is related to the vegetation density, diameter of the vegetation elements and drag coefficient. The model is verified by three numerical tests: flow in a 180° curved open channel with partial vegetation cover at the outer bank, flow in a rectangular channel with a finite patch of vegetation and flow in a rectangular channel with a vegetated bank. Numerical results are compared with the experimental data, and the good agreement proved that the presented model can model the vegetated channel flows correctly.
