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CFD模拟方法的发展成就与展望   总被引:13,自引:1,他引:12       下载免费PDF全文
本文综述了计算流体力学(computational fluid dynamics, CFD),尤其是计算空气动力学的发展概况.从计算方法、网格技术、湍流模型、大涡模拟等方面分别总结了CFD所取得的成就,分析了当前存在的问题、困惑,展望了其发展趋势.在CFD计算方法中,主要介绍了中心格式、迎风格式、TVD格式、WENO格式、紧致格式以及间断Galerkin有限元方法,对不同方法的原理和特性进行了系统阐述.网格技术包括结构网格、非结构网格、混合网格以及重叠网格,重点讨论了重叠网格的若干关键技术.在湍流模型中,对目前的模型进行分类介绍,包括线性涡黏性模型、二阶矩模型、非线性模型等,还介绍了转捩模型、DES方法以及SAS方法等.在大涡模拟方法中,就其中若干相关的研究方向进行了探讨,包括滤波方法、亚格子模型、收敛标准、数值格式等. 文中还包含了作者在相关领域的若干研究成果.  相似文献
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一种基于湍动能方程的转捩判定方法   总被引:2,自引:0,他引:2  
转捩现象是阻碍阻力高精度求解的主要问题之一.Menter和Langtry所提出的γ--θ转捩模型通过引入涡量雷诺数和间歇因子输运方程来驱动转捩,但是其中很多经验公式的理论立足点有待商榷.驱使层流转变到湍流依赖的仍然是平均速度的一阶和二阶相关量,它们组合构成了湍动能方程的耗散尺度.在湍动能方程中做合适的耗散平衡后,仅仅依靠湍动能方程可以有效地捕捉转捩现象.采用自然转捩和旁路转捩测试算例进行了验证,结果证明该方法与试验值匹配较好,具有一定的工程实用价值.  相似文献
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肖琦  王德弘  徐晶 《实验力学》2015,30(1):124-130
挤扩支盘桩是一种具有较高的承载力和较小的沉降变形的新桩型。对某220kV送电线路工程的挤扩支盘灌注桩分别开展了下压+水平联合工况、上拔+水平联合工况和水平荷载的现场真型静载荷试验,得到了挤扩支盘桩在不同工况下的承载力、桩身轴力、桩周侧阻力和桩端阻力的分布规律。支盘桩的抗拔承载力较普通灌注桩提高约20%,支盘的存在使得桩身轴力呈现明显的阶跃式变化。根据挤扩支盘桩的荷载传递规律,建议承力盘间距不小于桩身设计直径的4倍,且不小于承力盘设计直径的2倍。  相似文献
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Computations of wall distances still play a key role in modern turbulence modeling. Motivated by the expense involved in the computation, an approach solving partial differential equations is considered. An Euler-like transport equation is proposed based on the Eikonal equation. Thus, the efficient algorithms and code components developed for solving transport equations such as Euler and Navier-Stokes equations can be reused. This article provides a detailed implementation of the transport equation in the Cartesian coordinates based on the code of computational fluid dynamics for missiles (MICFD) of Beihang University. The transport equation is robust and rapidly convergent by the implicit lower-upper symmetric Gauss-Seidel (LUSGS) time advancement and upwind spatial discretization. Geometric derivatives must also be upwind determined to ensure accuracy. Special treatments on initial and boundary conditions are discussed. This distance solving approach is successfully applied on several complex geometries with 1–1 blocking or overset grids.  相似文献
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Prediction of the characteristics of turbulent flows with strong streamline curvature, such as flows in turbomachines, curved channel flows, flows around airfoils and buildings, is of great importance in engineering applications and poses a very practical challenge for turbulence modeling. In this paper, we analyze qualitatively the curvature effects on the structure of turbulence and conduct numerical simulations of a turbulent Uduct flow with a number of turbulence models in order to assess their overall performance. The models evaluated in this work are some typical linear eddy viscosity turbulence models, nonlinear eddy viscosity turbulence models (NLEVM) (quadratic and cubic), a quadratic explicit algebraic stress model (EASM) and a Reynolds stress model (RSM) developed based on the second-moment closure. Our numerical results show that a cubic NLEVM that performs considerably well in other benchmark turbulent flows, such as the Craft, Launder and Suga model and the Huang and Ma model, is able to capture the major features of the highly curved turbulent U-duct flow, including the damping of turbulence near the convex wall, the enhancement of turbulence near the concave wall, and the subsequent turbulent flow separation. The predictions of the cubic models are quite close to that of the RSM, in relatively good agreement with the experimental data, which suggests that these models may be employed to simulate the turbulent curved flows in engineering applications.  相似文献
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