The internal turbulent flow in conical diffuser is a very complicated adverse pressure gradient flow.DLR k-ε turbulence model was adopted to study it.The every terms of the Laplace operator in DLR k-ε turbulence mod...The internal turbulent flow in conical diffuser is a very complicated adverse pressure gradient flow.DLR k-ε turbulence model was adopted to study it.The every terms of the Laplace operator in DLR k-ε turbulence model and pressure Poisson equation were discretized by upwind difference scheme.A new full implicit difference scheme of 5-point was constructed by using finite volume method and finite difference method.A large sparse matrix with five diagonals was formed and was stored by three arrays of one dimension in a compressed mode.General iterative methods do not work wel1 with large sparse matrix.With algebraic multigrid method(AMG),linear algebraic system of equations was solved and the precision was set at 10-6.The computation results were compared with the experimental results.The results show that the computation results have a good agreement with the experiment data.The precision of computational results and numerical simulation efficiency are greatly improved.展开更多
本文在混合网格基础上用多重网格法求解了紊流 N- S方程。混合网格是由在物面附近采用的柱状网格与其他区域则采用的非结构网格组成。方程的求解采用 Jam son的有限体积法 ,紊流模型采用两层 Baldwin- L o-max代数紊流模型。用多重网格...本文在混合网格基础上用多重网格法求解了紊流 N- S方程。混合网格是由在物面附近采用的柱状网格与其他区域则采用的非结构网格组成。方程的求解采用 Jam son的有限体积法 ,紊流模型采用两层 Baldwin- L o-max代数紊流模型。用多重网格法来加速解的收敛。数值算例表明 ,用混合网格及多重网格法来求解紊流展开更多
基金Projects(59375211,10771178,10676031) supported by the National Natural Science Foundation of ChinaProject(07A068) supported by the Key Project of Hunan Education CommissionProject(2005CB321702) supported by the National Key Basic Research Program of China
文摘The internal turbulent flow in conical diffuser is a very complicated adverse pressure gradient flow.DLR k-ε turbulence model was adopted to study it.The every terms of the Laplace operator in DLR k-ε turbulence model and pressure Poisson equation were discretized by upwind difference scheme.A new full implicit difference scheme of 5-point was constructed by using finite volume method and finite difference method.A large sparse matrix with five diagonals was formed and was stored by three arrays of one dimension in a compressed mode.General iterative methods do not work wel1 with large sparse matrix.With algebraic multigrid method(AMG),linear algebraic system of equations was solved and the precision was set at 10-6.The computation results were compared with the experimental results.The results show that the computation results have a good agreement with the experiment data.The precision of computational results and numerical simulation efficiency are greatly improved.
文摘本文简要介绍了多重网格方法的基本思想和原理,然后应用多重网格（MG）方法求解三维泊松方程,网格尺度从17×17×17逐次增加至257×257×257,并与不完全Chelesky共轭梯度法（ICCG）、Gauss直接解法进行比较.结果表明,MG方法计算速度明显优于ICCG、Gauss方法,对于129×129×129网格的三维数值模拟费时43s,比ICCG法快7倍,而对于257×257×257超大型网格的三维数值模拟也仅需412 s.
文摘本文在混合网格基础上用多重网格法求解了紊流 N- S方程。混合网格是由在物面附近采用的柱状网格与其他区域则采用的非结构网格组成。方程的求解采用 Jam son的有限体积法 ,紊流模型采用两层 Baldwin- L o-max代数紊流模型。用多重网格法来加速解的收敛。数值算例表明 ,用混合网格及多重网格法来求解紊流
