共查询到19条相似文献，搜索用时 328 毫秒
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针对CAE仿真技术中偏微分方程数值模型求解的稳定性、准确性以及步长参数设置问题,采用CAE技术中常用的一阶迎风格式、Lax-Wendroff格式以及隐式中心格式分别对双曲偏微分方程数值模型进行计算分析.结果表明:Lax-Wendroff格式具有较高的求解精度,而隐式中心格式属于无条件稳定,其求解易于收敛;在满足差分计算稳定性的条件下,随着时间步长τ的减小,差分数值解的结果误差逐渐降低,但是其求解精度主要依赖合适的差分格式. 相似文献
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对一类两点边值常微分方程给出两种差分算法,一种算法具有一阶精度,另一种算法具有二阶精度,两种算法均得到的差分格式的系数矩阵为三对角矩阵,可用追赶法求解。并举数值例子来验证两种算法的精度。 相似文献
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三维对流扩散方程的高精度多重网格方法 总被引：1，自引：0，他引：1
在立方体网格上建立了数值求解三维变系数对流扩散方程的四阶精度19点紧致差分格式,采用多重网格加速技术,建立了适用于本文高精度紧致差分格式的多重网格算法,从而大大加快了传统迭代法的收敛速度。数值实验结果表明本文方法对于不同的网格雷诺数问题,在准确性、稳定性以及减少计算工作量方面均明显优于7点中心差分格式。 相似文献
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对一维线性Schrdinger方程的初边值问题给出了紧差分格式,证明了该格式满足电荷和能量守恒关系,并用能量方法证明了格式的收敛性和稳定性,最后给出了数值结果,结果表明本文格式的精度具有O(τ2+h4). 相似文献
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利用一阶和二阶导数的四阶padé型紧致差分逼近式,结合原方程本身,得到了两点边值问题的一种四阶精度的隐式紧致差分格式。该格式仅涉及未知量及其一阶导数和二阶导数值,推导过程简便。并且利用泰勒展开得到了一阶和二阶导数在边界点处的同阶离散格式。数值算例表明:文中格式较以往的格式具有更高的精度,并且计算简便。 相似文献
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研究了二维变系数非齐次热传导方程的两层绝对稳定的差分格式问题。首先运用Pade逼近导出了差分格式,给出了差分格式的截断误差;讨论了差分格式的绝对稳定性和收敛性,且收敛阶为O(2τ+h4);最后给出了数值例子,数值结果和理论结果是吻合的。 相似文献
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对二维线性方程给出一种紧差分格式,证明了该格式满足电荷守恒关系且是收敛稳定的,在数值实验中给出了数值计算的实验结果,通过计算表明这个格式精度具有O（τ^2＋h^4）。 相似文献
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本文对带有齐次边界条件的BBM-KdV方程的初边值问题进行了数值方法研究,在保证具有二阶理论精度的前提下,将非线性项在时间层进行线性化离散,提出了一个两层线性差分格式,且该格式合理地模拟了原问题的一个守恒性质,并用能量方法证明了其解的存在唯一性、二阶收敛性和无条件稳定性,最后的数值实验表明,该方法是有效的,且明显优于其它二阶格式. 相似文献
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Abstract In this paper, the evaluation of discretely sampled Asian options was considered by numerically solving the associated partial differential equations with the Legendre spectral method. Double average options were discussed as examples. The problem is a parabolic one on a finite domain whose equation degenerates into ordinary differential equations on the boundaries. A fully discrete scheme was established by 相似文献
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A second-order mixing difference scheme with a limiting factor is deduced with the reconstruction gradient method and applied
to discretizing the Navier-Stokes equation in an unstructured grid. The transform of nonorthogonal diffusion items generated
by the scheme in discrete equations is provided. The Delaunay triangulation method is improved to generate the unstructured
grid. The computing program based on the SIMPLE algorithm in an unstructured grid is compiled and used to solve the discrete
equations of two types of incompressible viscous flow. The numerical simulation results of the laminar flow driven by lid
in cavity and flow behind a cylinder are compared with the theoretical solution and experimental data respectively. In the
former case, a good agreement is achieved in the main velocity and drag coefficient curve. In the latter case, the numerical
structure and development of vortex under several Reynolds numbers match well with that of the experiment. It is indicated
that the factor difference scheme is of higher accuracy, and feasible to be applied to Navier-Stokes equation. 相似文献
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对二维热传导方程进行紧交替方向有限差分,该方法在空间方向上具有四阶精度,在时间方向上具有二阶精度。证明了当rx,ry≥1／6时该有限差分解收敛于连续解。数值例子验证了该有限差分法具有高阶精度。 相似文献
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A finite difference lattice Boltzmann method of second-order accuracy in time is developed based on non-oscillatory scheme with no-free-parameter dissipation (NND) difference scheme in this paper. The NND lattice Boltzmann method is used to simulate high-speed flows by constructing a new equilibrium distribution function of the lattice Boltzmann method.Compared with a variation of lattice Boltzmann method developed by Qu, et al., the present method can capture shock waves and handle oscillations of high velocity flows accurately in larger time steps and in shorter computing time. Numerical results indicate the correctness and capability of simulating shock wave interactions of the NND lattice Boltzmann method. 相似文献
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INTRODUCTION Structural damage detection technique addresses the problem of how to locate and detect damage that occurred in a structure by using the observed changes of its dynamic and static characteristics. In recent years, damage assessment of structure has drawn wide attention from various engineering fields. Gen-erally, the existing approaches proposed in this area can be clarified into two major categories: the dy-namic identification methods using dynamic test data and the static … 相似文献
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针对多管落球法测液体黏滞系数的实验中,小球下落偏离轴线、环境温度变化的影响、人工计时和小球下落距离测量不准的问题,提出改进小球取用工具以保证小球沿轴线向下落,调整测量顺序并采用光电法测量小球下落时间,改进测量小球下落距离的方法等,以保证准确测量。通过改进,实验误差大大降低。 相似文献
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Sarah J. Grigg 《European Journal of Engineering Education》2014,39(6):617-635
This study describes the development and structure of a coding scheme for analysing solutions to well-structured problems in terms of cognitive processes and problem-solving deficiencies for first-year engineering students. A task analysis approach was used to assess students’ problem solutions using the hierarchical structure from a theoretical framework from mathematics research. The coding scheme comprises 54 codes within the categories of knowledge access, knowledge generation, self-management, conceptual errors, mechanical errors, management errors, approach strategies and solution accuracy, and was demonstrated to be both dependable and credible for analysing problems typical of topics in first-year engineering courses. The problem-solving processes were evaluated in terms of time, process elements, errors committed and self-corrected errors. Therefore, problem-solving performance can be analysed in terms of both accuracy and efficiency of processing, pinpointing areas meriting further study from a cognitive perspective, and for documenting processes for research purposes. 相似文献
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研究了基于内置光纤进行高电压系统温度在线监测,阐述了该研究的结构、原理及系统的软硬件设计方案,并对装置的精度进行测试.测试结果表明,该方案能很好地解决高电压系统温度在线监测存在的问题. 相似文献
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吴开腾 《内江师范学院学报》2008,23(12)
分析了基本无振荡(ENO)格式的特点,重构多项式是ENO格式构造的核心部分;由通量值作为插值点,构造了一个简单的高精度格式;引入三阶TVD Runge-Kutta时间离散;编写了基于ENO格式的三维计算程序;就三维欧拉方程的激波反射与双赫反射问题进行了数值计算,给出了空中爆炸场的三维压力分布图.数值试验结果表明,格式所具有的高精度和基本无振荡性质,能够满足实际计算的需要. 相似文献