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R-M不稳定性数值模拟方法 总被引:4,自引:0,他引:4
1.引 言 受扰动的两轻重流体的交界面,当处于方向由重流体指向轻流体的有效重力场中或受到冲击波作用时扰动将发展,界面将失稳,两种物质将发生湍流混合.重力场作用下的不稳定性,人们常称为Rayleigh-Taylor(简称R-T)不稳定性,激波作用下的界面不稳定性,则常称为 Richtmyer-Meshkov(简称 R-M)不稳定性.在惯性约束核聚变(ICF)中,由于R-T和R-M不稳定性的作用,将影响到氘氚气体的内爆压缩、升温、点火和燃烧[7]. 界面不稳定性的研究因其应用背景和学术价值在近二十多年受… 相似文献
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In the paper, the numerical simulation of interface problems for multiple material fluids is studied. The level set function is designed to capture the location of the material interface. For multi-dimensional and multi-material fluids, the modified ghost fluid method needs a Riemann solution to renew the variable states near the interface. Here we present a new convenient and effective algorithm for solving the Riemann problem in the normal direction. The extrapolated variables are populated by Taylor series expansions in the direction. The anti-diffusive high order WENO difference scheme with the limiter is adopted for the numerical simulation. Finally we implement a series of numerical experiments of multi-material flows. The obtained results are satisfying, compared to those by other methods.The English text was polished by Boyi Wang. 相似文献
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研究了在Burgers方程跨声速稀疏波计算中遇到的sonic point glitch问题,对它产生的原因及其与数值格式熵条件的关系进行了分析.对若干著名格式,按照是否满足熵条件进行了分类.为了消除sonic point glitch现象,提出了一种新的两步分裂方法,并用这种方法改进了一系列典型格式.数值试验表明这是一种很好的消除sonic point glitch的方法. 相似文献
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Gui-Qiang G.Chen School of Mathematical Sciences Fudan University Shanghai China Mathematical Institute University of Oxford - St Giles Oxford OX LB UK 《数学物理学报(B辑英文版)》2010,30(2):391-427
We are concerned with the derivation and analysis of one-dimensional hyperbolic systems of conservation laws modelling fluid flows such as the blood flow through compliant axisymmetric vessels.Early models derived are nonconservative and/or nonhomogeneous with measure source terms,which are endowed with infinitely many Riemann solutions for some Riemann data.In this paper,we derive a one-dimensional hyperbolic system that is conservative and homogeneous.Moreover,there exists a unique global Riemann solution for the Riemann problem for two vessels with arbitrarily large Riemann data,under a natural stability entropy criterion.The Riemann solutions may consist of four waves for some cases.The system can also be written as a 3×3 system for which strict hyperbolicity fails and the standing waves can be regarded as the contact discontinuities corresponding to the second family with zero eigenvalue. 相似文献
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多相流界面存在密度、黏性等物理场间断,直接采用传统光滑粒子水动力学(smoothedparticle hydrodynamics,SPH)方法进行数值模拟,界面附近的压力和速度存在震荡.一套基于黎曼解能够处理大密度比的多相流SPH计算模型被提出,该模型利用黎曼解在处理接触间断问题方面的优势,将黎曼解引入到SPH多相流计算模型中,为了能够准确求解多相流体物理黏性、减小黎曼耗散,对黎曼形式的SPH动量方程进行了改进,又将Adami固壁边界与黎曼单侧问题相结合来施加多相流SPH固壁边界,同时模型中考虑了表面张力对小尺度异相界面的影响,该模型没有添加任何人工黏性、人工耗散和非物理人工处理技术,能够反应多相流真实物理黏性和物理演变状态.采用该模型首先对三种不同粒子间距离散下方形液滴震荡问题进行了数值模拟,验证了该模型在处理异相界面的正确性和模型本身的收敛性;后又通过对Rayleigh--Taylor不稳定、单气泡上浮、双气泡上浮问题进行了模拟计算,结果与文献对比吻合度高,异相界面捕捉清晰,结果表明,本文改进的多相流SPH模型能够稳定、有效的模拟大密度比和黏性比的多相流问题. 相似文献
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基于Roe的空间离散格式,以绕ONERAM6、LANN机翼流场为算例,分别以Euler和N-S方程为主控方程,对尾迹面法气动力积分技术进行初步探讨,重点讨论了尾迹面位置对气动力的影响。引入不同尾迹插值方法,研究了不同插值方法对气动力积分结果的影响,为气动力的精确性计算提供了气动分析平台。研究结果表明:当尾迹面的位置处于机翼后0.5到1.5倍平均气动弦范围内时,此方法具备较好的气动力积分精度;与中心插值相比,基于格心距离加权的流动参数插值有更高的积分精度。 相似文献
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