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An improved WENO-Z scheme with symmetry-preserving mapping

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Advances in Aerodynamics 2020年第1期2卷 342-372页

作者： Zheng Hong zhengyin ye Kun ye National Key Laboratory of Science and Technology on Aerodynamic Design and Research Northwestern Polytechnical UniversityXi’an 710072China

Since the classical weighted essentially non-oscillatory(WENO)scheme is proposed,various improved versions have been developed,and a typical one is the WENO-Z *** better resolution is achieved,it is shown in this article that,the result of WENO-Z scheme suffers evident distortion in the long-time simulation of the linear advection *** order to fix the problem of WENO-Z,a symmetrypreserving mapping method is proposed in this *** the original mapping method,the weight of each sub-stencil is used to map,which is demonstrated to cause asymmetric improvement about a *** asymmetric improvement will lead to a distorted solution,more severe with longer output *** the symmetry-preserving mapping method,a new variable related to the smoothness indicator is selected to map,which has the same ideal value for each *** the new mapping method can not only fix the distortion problem of WENO-Z,but also improve the numerical *** benchmark problems are conducted to show the improved performance of the resultant scheme.

关键词： WENO-Z Mapping method Nonlinear weights Hyperbolic conservation laws

Drag Reduction for an Airship with Proper Arrangement of Propellers

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Chinese Journal of Aeronautics 2009年第6期22卷 575-582页

作者： Xie Fei ye zhengyin School of Aeronautics Northwestern Polytechnical University Xi 'an 710072 China

In this article, the flow field around an airship with propellers blowing is calculated on the basis of the Reynolds-averaged Navier-Stokes equations with SST turbulent models. Modeled each as an actuator disk, the propellers are arranged at different positions around the body of airship in the flow direction. The numerical results show that the blowing propellers produce open outer flows. They drive the separated vortexes off the body thus reducing the drag coefficients. The results also show that the position after leading sucking peak is the best place for a propeller to blow. When the propellers are positioned after sucking peak, the longer the area which the propellers work on, the more the profile drag coefficients can be reduced. If the working position of propeller moves from the sucking peak forward to the leading edge, the friction drag coefficient will increase. The bigger the diameter of the propellers and the stronger the pressure jump, the more the drag coefficient will be reduced. The re- suits also reveal that for the design of circularly-positioned propellers with space intervals, the more drag coefficient reduction results, the smaller the space interval is specified.

关键词： separation airship drag coefficient actuator propeller

An Improved LU-SGS Implicit Scheme for High Reynolds Number Flow Computations on Hybrid Unstructured Mesh

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Chinese Journal of Aeronautics 2012年第1期25卷 33-41页

作者： WANG Gang JIANG Yuewen ye zhengyin National Key Laboratory of Science and Technology on Aerodynamic Design and Research Northwestern Polytechnical UniversityXi'an 710072China

The lower-upper symmetric Gauss-Seidel （LU-SGS） implicit relaxation has been widely used because it has the merits of less dependency on grid topology, low numerical complexity and modest memory requirements. In original LU-SGS scheme, the implicit system matrix is constructed based on the splitting of convective flux Jacobian according to its spectral radius. Although this treatment has the merit of reducing computational complexity and helps to ensure the diagonally dominant property of the implicit system matrix, it can also cause serious distortions on the implicit system matrix because too many approximations are introduced by this splitting method if the contravariant velocity is small or close to sonic speed. To overcome this shortcoming, an improved LU-SGS scheme with a hybrid construction method for the implicit system matrix is developed in this paper. The hybrid way is that： on the cell faces having small contravariant velocity or transonic contravariant velocity, the accurate derivative of the convective flux term is used to construct more accurate implicit system matrix, while the original Jacobian splitting method is adopted on the other cell faces to reduce computational complexity and ensure the diagonally dominant property of the implicit system matrix. To investigate the convergence performance of the improved LU-SGS scheme, 2D and 3D turbulent flows around the NACA0012 airfoil, RAE2822 airfoil and LANN wing are simulated on hybrid unstructured meshes. The nu- merical results show that the improved LU-SGS scheme is significantly more efficient than the original LU-SGS scheme.

关键词： LU-SGS scheme hybrid unstructured mesh Navier-Stokes equations flux Jacobian convergence performance turbulent flow

The CDF and its sensitivity analysis of stochastic structure with stochastic excitation by advanced stratified line sampling

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Science China(Physics,Mechanics & Astronomy) 2013年第8期56卷 1559-1567页

作者： SONG ShuFang LU ZhenZhou ZHANG WeiWeiNational Key Laboratory of Aerodynamic Design and Research Northwestern Polytechnical University ye zhengyin School of Aeronautics Northwestern Polytechnical University National Key Laboratory of Aerodynamic Design and Research Northwestern Polytechnical University

For the stochastic structure with stochastic excitation, an advanced stratified line sampling (SLS) method is presented to obtain the cumulative distribution function (CDF) of the structural response and its sensitivity. The advanced stratified line sampling method introduces a set of middle failure subsets firstly. And for each subset, the conventional line sampling can be used to obtain the corresponding value of the response's CDF. At the same time, the sensitivity estimations of each failure subset can also be computed by modifying the important direction and corresponding reliability coefficients. The properties of CDF sensitivity are proved while the performance function is linear with normal random variables. After two simple examples are used to demonstrate the properties of CDF sensitivity and the feasibility of the presented method, the method employed to analyze the CDF and corresponding sensitivity of root bending moment (RBM) responses for the stochastic BAH is wing with gust excitation to a square-edged gust and to a Dryden gust. The results show that the parameters of the second and the fifth order modals exert more influence on the CDF of response than the other ones, and the presented SLS method can more significantly reduce the computational cost compared with Monte Carlo simulation (MCS).

关键词： stochastic excitation line sampling cumulative distribution function (CDF) sensitivity analysis root bending moment (RBM) gust response analysis

Reliability and Sensitivity Analysis of Transonic Flutter Using Improved Line Sampling Technique

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Chinese Journal of Aeronautics 2009年第5期22卷 513-519页

作者： Song Shufang Lu Zhenzhou Zhang Weiwei ye zhengyin School of Aeronautics Northwestern Polytechnical University Xi'an 710072 China National Key Laboratory of Aerodynamic Design and Research Northwestern Polytechnical University Xi'an 710072 China

The improved line sampling （LS） technique, an effective numerical simulation method, is employed to analyze the probabilistic characteristics and reliability sensitivity of flutter with random structural parameter in transonic flow. The improved LS technique is a novel methodology for reliability and sensitivity analysis of high dimensionality and low probability problem with implicit limit state function, and it does not require any approximating surrogate of the implicit limit state equation. The improved LS is used to estimate the flutter reliability and the sensitivity of a two-dimensional wing, in which some structural properties, such as frequency, parameters of gravity center and mass ratio, are considered as random variables. Computational fluid dynamics （CFD） based unsteady aerodynamic reduced order model （ROM） method is used to construct the aerodynamic state equations. Coupling structural state equations with aerodynamic state equations, the safety margin of flutter is founded by using the critical velocity of flutter. The results show that the improved LS technique can effectively decrease the computational cost in the random uncertainty analysis of flutter. The reliability sensitivity, defined by the partial derivative of the failure probability with respect to the distribution parameter of random variable, can help to identify the important parameters and guide the structural optimization design.

关键词： flutter aeroelastic line sampling technique Monte Carlo simulation uncertainty reduced order model

Quasi-Hamiltonian principle of liquid-filled elastic body dynamics

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Science China(Physics,Mechanics & Astronomy) 2010年第6期53卷 1116-1123页

作者： HAO MingWang & ye zhengyin National Key Laboratory of Aerodynamic Design and Research,Northwestern Polytechnical University,Xi’an 710072,China National Key Laboratory of Aerodynamic Design and Research Northwestern Polytechnical University Xi’an China

Liquid-filled elastic body dynamics is an important branch of fluid-solid coupling mechanics. It deals with the study of motion of a body and the liquid contained in the body under the interaction between the two,for example,a liquid-filled satellite,a fuel tank of an airplane,etc. The research on liquid-filled elastic body dynamics is usually done by the variational method since the method has a feature of treating things as a whole. Considering the elastic motion of the liquid-filled body and the surface tension effect on the liquid-gas interface,liquid-solid interface and gas-solid interface,the present paper establishes a quasi-Hamiltonian variational principle for the above-mentioned system. After finding the stationary-value conditions of its functional obtained,a complete system of governing equations consisting of the stationary value conditions,preconditions and constraint conditions is established,and then the equations are reduced into some known ones in a special case.

关键词： fluid-solid coupling quasi-Hamiltonian variational principle liquid-filled elastic body incompressible fluid

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转捩位置对全动舵面热气动弹性的影响

力学学报 2017年第4期49卷 802-810页

作者：刘成叶正寅叶坤西北工业大学航空学院西安710072

高超声速附面层的转捩预测一直是流体力学研究中的难点,转捩前后物面的摩擦系数和传热系数会发生改变,转捩位置的不同会影响到飞行器表面热环境,进而使得飞行器的气动弹性特性发生显著变化.鉴于高超声速附面层转捩预测的不确定性,本文... 详细信息

高超声速附面层的转捩预测一直是流体力学研究中的难点,转捩前后物面的摩擦系数和传热系数会发生改变,转捩位置的不同会影响到飞行器表面热环境,进而使得飞行器的气动弹性特性发生显著变化.鉴于高超声速附面层转捩预测的不确定性,本文分析了转捩位置对高超声速全动舵面热气动弹性的影响.首先分别用层流模型和湍流模型求解N-S方程,得到气动热环境,并对气动热进行参数化;然后在不同转捩位置情况下构造出不同转捩位置的热分布模型,基于此种温度分布,结合热应力和材料属性的影响分析结构的热模态,将结构模态插值到气动网格上,采用基于CFD的当地流活塞理论进行气动弹性分析.以M=6,H=15 km的某舵面为对象进行计算,结果表明:(1)随着转捩位置向后缘移动,结构频率上升,结构颤振速度呈增大趋势,转捩位置的变化能够带来颤振临界速度最大6%的变化量;(2)当转捩位置位于舵轴附近时,结构的颤振特性变化剧烈.通过刚度特性的分解和分析发现,导致颤振特性变化的主要因素在于舵轴的刚度特性变化,舵轴的影响量占整个结构刚度特性变化量的80%以上.

关键词：高超声速附面层转捩热气动弹性不确定性当地流活塞理论

NACA0012翼型跨声速强迫运动非定常气动力模型

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哈尔滨工程大学学报 2020年第11期41卷 1683-1688页

作者：张庆叶正寅西安航空学院飞行器学院陕西西安710077 南洋理工大学机械与航空工程学院新加坡639798 西北工业大学航空学院陕西西安710072

传统的一阶线性叠加的气动力模型不再适用于现代高机动性飞行器的非定常气动力建模,为了考察更高阶的气动力模型对非定常迟滞效应模拟的适用程度,本文采用自主发展的求解器,分别计算了NACA0012翼型在跨声速来流条件下做单自由度强迫沉... 详细信息

传统的一阶线性叠加的气动力模型不再适用于现代高机动性飞行器的非定常气动力建模,为了考察更高阶的气动力模型对非定常迟滞效应模拟的适用程度,本文采用自主发展的求解器,分别计算了NACA0012翼型在跨声速来流条件下做单自由度强迫沉浮、俯仰以及沉浮/俯仰两自由度耦合运动的非定常气动力的变化规律。然后在Etkin气动力模型的基础上,探讨了不同类型的高阶的气动导数在非定常气动力建模中的作用。研究结果表明:将Etkin气动力模型中升力和俯仰力矩对迎角的导数项由一阶拓展至二阶就可以较为精确地重构出翼型在强迫运动各阶段的非定常升力和俯仰力矩。

关键词：跨声速气动导数气动力建模沉浮运动俯仰运动耦合运动 Etkin模型非定常气动力

激波主导流动下壁板的热气动弹性稳定性理论分析

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力学学报 2018年第2期50卷 221-232页

作者：叶柳青叶正寅西北工业大学航空学院西安710072

针对激波主导流动下弹性壁板的热气动弹性稳定性分析问题,建立了基于当地活塞流理论的分析模型,并用数值仿真方法来验证其正确性.首先基于Hamilton原理和Von-Karman大变形理论,建立壁板的热气动弹性运动方程,其中假设壁板受热后温度均... 详细信息

针对激波主导流动下弹性壁板的热气动弹性稳定性分析问题,建立了基于当地活塞流理论的分析模型,并用数值仿真方法来验证其正确性.首先基于Hamilton原理和Von-Karman大变形理论,建立壁板的热气动弹性运动方程,其中假设壁板受热后温度均匀分布,激波前后区域的气动力模型采用当地一阶活塞流理论;利用Galerkin方法将具有连续参数系统的偏微分颤振方程离散为有限个自由度的常微分方程;基于李雅普诺夫间接法将非线性颤振方程组在平衡位置处进行线化,再用Routh-Hurwits判据来判断线性系统的稳定性,从而来推论出非线性颤振系统的气动弹性稳定性.在时域中采用龙格-库塔法对非线性颤振方程进行数值积分,得到壁板非线性颤振响应的时间历程,与理论分析结果进行对比.研究结果表明,壁板受到斜激波冲击时,更容易发生颤振失稳,并且激波强度越大,极限环幅值和频率越大;激波主导流场中的壁板失稳边界不同于传统单纯超声速气流中壁板颤振的失稳边界;只有在斜激波前后不同的动压值都满足颤振稳定性边界的条件下,壁板才可能保持其气动弹性稳定性.

关键词：激波热气动弹性稳定性壁板颤振当地活塞流理论