共查询到20条相似文献,搜索用时 78 毫秒
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多级轴流压气机全工况特性计算 总被引:1,自引:0,他引:1
本文使用三维粘性流动计算软件Fine/Numeca,对某十五级轴流压气机进行了内流流场和全工况特性的数值计算尝试。分析了该压气机在设计工况和非设计工况的性能,同时把整机计算结果和前七级叶片的计算结果进行了比较。计算结果表明,当计算的级数较少时,目前的软件和硬件平台可以比较合理地预测压气机的全工况特性;而当计算的级数较多时,准确的数值模拟仍需要更为准确的多级模型和数值方法。 相似文献
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中子裂变链统计涨落问题的数值计算方法 总被引:1,自引:0,他引:1
研究了弱中子源驱动下,裂变系统中子裂变链统计涨落问题的数值计算方法。进行了数值计算建模、数值方法分析、数值计算检验、一类问题概率分布函数的统计涨落特征量的数值计算示范。特例数值检验表明:只要数值解方程组阶数(截断) N足够大,数值解满足归一(守恒) 律、指数增长律,并与精确解析解一致。对于非定常裂变系统中子裂变链统计涨落问题提出了一维等效模型下数值模拟的方法。 相似文献
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根据在表面-等离子体型负离子源中,负离子主要由转换电极表面产生这一特点,参考正离子源引出系统数值计算程序,建立了负离子源引出系统的数值计算模型和计算程序;对表面-等离子体型桶式负离子源引出系统束光学的性质进行了数值模拟。对计算结果的检验和分析表明,这个计算模型和程序反映了负离子源引出系统束光学的基本特性。 相似文献
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发展了一种三维有限元数值模型和计算方法来对矩形流管声场进行整体的计算.与以往的二维方法相比,此种数值方法不仅全面反映了矩形流管内声波的传播情况,而且提高了网格精度,从而大大扩展了对铺设有声衬的流管的计算领域.结果表明,该数值模型是有效和准确的,与其它方法和文献的计算结果吻合得非常好.同时,在大大增加计算量的同时,也对程序代码进行了优化工作,提高了计算效率. 相似文献
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采用体积加速度模型确定水下爆炸气泡运动的初始条件,基于MSC.DYTRAN有限元软件开发了定义流场初始条件和边界条件的子程序,对气泡在水平刚性壁面附近的运动特性进行了数值模拟,通过对比发现数值计算结果与实验结果具有较好的一致性,证明了初始条件定义、子程序开发和有限元模型建立的正确性和数值计算的准确性。以此为基础,研究了水深、泡心与刚性底面之间的距离对气泡动态特性和射流速度的影响,通过数值计算得到了一些有规律的曲线。计算模型、方法及结果对相关的工程研究和计算具有一定的参考价值。 相似文献
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While the approximate solutions of one-dimensional nonlinear Volterra-Fredholm integral equations with smooth kermels are now well understood,no systematic studies of the numerical solutions of their multi-dimensional counterparts exist.In this paper,we provide an efficient numerical approach for the multi-dimensional nonlinear Volterra-Fredholm integral equations based on the multi-variate Legendre-collocation approach.Spectral collocation methods for multi-dimensional nonlinear integral equations are known to cause major difficulties from a convergence analysis point of view.Consequently,rigorous error estimates are provided in the weighted Sobolev space showing the exponential decay of the numerical errors.The existence and uniqueness of the numerical solution are established.Numerical experiments are provided to support the theoretical convergence analysis.The results indicate that our spectral collocation method is more flexible with better accuracy than the existing ones. 相似文献
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S. Mahdavifar 《The European Physical Journal B - Condensed Matter and Complex Systems》2010,77(1):77-82
The ground state magnetic phase diagram of the
one-dimensional quantum compass model (QCM) is studied using the
numerical Lanczos method. A detailed numerical analysis of the low
energy excitation spectrum is presented. The energy gap and the
spin-spin correlation functions are calculated for finite chains.
Two kind of the magnetic long-range orders, the Néel
and a type of the stripe-antiferromagnet, in the ground state
phase diagram are identified. Based on the numerical analysis, the
first and second order quantum phase transitions in the ground
state phase diagram are identified. 相似文献
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V. YILDIRIM 《Journal of sound and vibration》2002,252(3):479-491
Numerical and analytical studies are performed for the free vibration analysis of non-cylindrical (conical, barrel and hyperboloidal types) helical springs. The stiffness matrix method is used in the numerical analysis. A total of 12 degrees of freedom (six displacements and six rotations) is described for an element. The exact element stiffness matrix and the exact concentrated element inertia matrix are used in the formulation. The rotary inertia, the shear and extensional deformation effects are considered in the analysis. Comparison of the numerical results with the reported results obtained numerically and experimentally gives satisfactory values. After verification of the numerical frequencies, the non-dimensional fundamental frequencies of fixed-fixed non-cylindrical helical springs with circular section are expressed in a simple formula with a maximum absolute relative error of 5% using those numerical values for the constant helix pitch angles (5°, 10°, and 15°). These expressions restricted to the fundamental frequencies are also verified with ANSYS results. 相似文献
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The numerical simulation method of radiative entropy generation in participating media presented by Caldas and Semiao [Entropy generation through radiative transfer in participating media: analysis and numerical computation. JQSRT 2005;96:423-37] is extended to analyze the radiative entropy generation in the enclosures filled with semitransparent media. A discrete ordinates method is used to solve radiative transfer equation and radiative entropy generation. Two different examples are employed to verify the numerical simulation method of radiative entropy generation in the enclosure. Numerical results of dimensionless radiative entropy generation of enclosure are identical to that of entire thermodynamics analysis for the enclosure system. This numerical simulation method can be used in the entropy generation analysis of high-temperature systems such as boilers and furnaces, in which radiation is the dominant mode of heat transfer. 相似文献
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Hydrothermal convection of pore water with a temperature-dependent viscosity within a permeable, internally heated, moderately thin spherical shell is investigated by both a perturbation analysis and a direct numerical simulation. The analysis and simulation are mainly focused on a thin spherical shell in that convective instabilities are characterized by the spherical harmonic degree l=6 with a 13-fold mathematical degeneracy. Four different three-dimensional analytical solutions of convection are derived by removing the degeneracy through the nonlinear effect. A direct numerical simulation of the nonlinear problem is also carried out, showing satisfactory agreement between the analytical solutions and the numerical simulations. 相似文献
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The harmonic generation of high power microwave in plasma filled waveguide is studied and the analytical theory is presented,
and the numerical calculation and analysis of second harmonic are done in this paper. The theoretical and numerical analysis
show that high power microwave can generate harmonic in the plasma filled waveguide. 相似文献
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The enhancement of heat transfer in a cavity was investigated in the absence of and in the presence of acoustic streaming
induced by ultrasonic waves. The present study provides the experimental and numerical results of heat transfer in the acoustic
fields. The enhancement of heat transfer was experimentally investigated in the presence of acoustic streaming and was compared
with the profiles of acoustic pressure calculated by the numerical analysis. A coupled finite element-boundary element method
(FE-BEM) was applied for a numerical analysis. Experimental and numerical studies clearly show that pressure variations are
closely related to the enhancement of heat transfer in the acoustic fields. 相似文献
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Xue-Nian Cao Jiang-Li Fu & Hu Huang 《advances in applied mathematics and mechanics.》2012,4(6):848-863
In this paper, a new numerical algorithm
for solving the time fractional Fokker-Planck equation is proposed. The
analysis of local truncation error and the stability of this method are
investigated. Theoretical analysis and numerical experiments show that
the proposed method has higher order of accuracy for solving the
time fractional Fokker-Planck equation. 相似文献