针对传统的基于Delaunay三角网的逐点内插算法难以同时兼顾精度和效率的问题,依据Voronoi单胞和Delaunay三角形的几何特性,提出了一种基于局部动态最优Delaunay三角网的逐点内插算法,并在格网数字水深模型(grid digital depth model,Gri...针对传统的基于Delaunay三角网的逐点内插算法难以同时兼顾精度和效率的问题,依据Voronoi单胞和Delaunay三角形的几何特性,提出了一种基于局部动态最优Delaunay三角网的逐点内插算法,并在格网数字水深模型(grid digital depth model,Grid-DDM)中进行应用。实验结果表明,该改进算法能保证插值精度并明显提高执行效率。展开更多
The laminar and turbulent flows past an axi-symmetric body with a ring wingwere investigated numerically at various attack angles (0°-20°) for the Reynolds numbers rangingfrom 10~3 to 10~7. The DDM (Domain D...The laminar and turbulent flows past an axi-symmetric body with a ring wingwere investigated numerically at various attack angles (0°-20°) for the Reynolds numbers rangingfrom 10~3 to 10~7. The DDM (Domain Decomposition Method) with the Schwarz iterative method based onfinite difference approximation was applied to simulate this problem. The primitive variableformulation was used for the solution of the incompressible Navier-Stoke equations. The velocityfield was calculated from the unsteady momentum equation by marching in time. The continuityequation was replaced by a Poisson-type equation for the pressure with the Neumann boundaryconditions. The Baldwin-Lomax model was adopted to simulate turbulence effect. The leap frogimplicit iterative method was used for the time difference approximations. The computed pressure atthe front stagnation point is found to have a small deviation, less than 10%, from the theoreticalvalue. The outlet flux has a loss about 5%. The lift coefficients increase linearly with the attackangle, but for attack angles greater than 15° the lift coefficients show mild decrease. Thefriction drag coefficients are insensitive to the attack angles, but the pressure drag coefficientsincrease markedly with the attack angles. In addition, complex flow patterns are revealed within thevicinity of the ring wing.展开更多
文摘针对传统的基于Delaunay三角网的逐点内插算法难以同时兼顾精度和效率的问题,依据Voronoi单胞和Delaunay三角形的几何特性,提出了一种基于局部动态最优Delaunay三角网的逐点内插算法,并在格网数字水深模型(grid digital depth model,Grid-DDM)中进行应用。实验结果表明,该改进算法能保证插值精度并明显提高执行效率。
文摘The laminar and turbulent flows past an axi-symmetric body with a ring wingwere investigated numerically at various attack angles (0°-20°) for the Reynolds numbers rangingfrom 10~3 to 10~7. The DDM (Domain Decomposition Method) with the Schwarz iterative method based onfinite difference approximation was applied to simulate this problem. The primitive variableformulation was used for the solution of the incompressible Navier-Stoke equations. The velocityfield was calculated from the unsteady momentum equation by marching in time. The continuityequation was replaced by a Poisson-type equation for the pressure with the Neumann boundaryconditions. The Baldwin-Lomax model was adopted to simulate turbulence effect. The leap frogimplicit iterative method was used for the time difference approximations. The computed pressure atthe front stagnation point is found to have a small deviation, less than 10%, from the theoreticalvalue. The outlet flux has a loss about 5%. The lift coefficients increase linearly with the attackangle, but for attack angles greater than 15° the lift coefficients show mild decrease. Thefriction drag coefficients are insensitive to the attack angles, but the pressure drag coefficientsincrease markedly with the attack angles. In addition, complex flow patterns are revealed within thevicinity of the ring wing.
