共查询到16条相似文献,搜索用时 62 毫秒
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对RGFM中定义Riemann问题的方式进行改进,取距离界面适当远处的插值点处的状态作为Riemann问题的初值.并用数值算例对改进前后的RGFM进行比较. 相似文献
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虚拟流体方法为模拟具有清晰物质界面的多介质流动问题提供了一种简便途径.尤其基于多介质Riemann问题解的修正虚拟流体方法及其变体,能够真实考虑到界面附近非线性波的相互作用和物质性质的影响,可以有效解决各种界面强间断等挑战性难题,具有巨大的工程应用潜力.文章重点回顾了虚拟流体方法的发展历史,总结和对比了各种代表性版本在模拟可压缩多介质流时的界面条件定义方式和多维推广方式,并介绍了该方法的设计原则和精度分析方面的研究进展.文章还回顾了该方法在其他更广泛和更具挑战性典型科学问题中的最新应用进展,并对方法的优势和特点进行了总结. 相似文献
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通过在界面处构造Riemann问题,根据流体的法向速度和压力在界面(接触间断)处连续的特性,利用Riemann问题的解不仅定义了ghost流体的值,而且对真实流体中邻近界面的点值进行了更新,使得在界面处的流体的状态满足接触间断的性质,给出了更加精确的界面边界条件,守恒误差分析表明该方法在界面计算过程中引入较小的误差.数值试验表明该方法能准确地捕捉界面和激波的位置. 相似文献
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基于流体体积分数的混合型多流体数值模型,将Piecewise Parabolic Method(PPM)方法应用于可压缩多流体流动的数值模拟,采用双波近似求解多流体van der Waals状态方程的Riemann问题.模拟高密度比且含有激波的可压缩多流体流动,典型的纯界面平移问题模拟结果表明,在接触间断的界面附近,压力和速度没有任何的振荡且界面数值耗散都被控制在2—3个网格之内;一维和二维算例表明,该数值方法可以有效地处理接触间断、激波和多维滑移线等物理问题,并能够比其它多流体数值方法更精细地模拟多流体交界面. 相似文献
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Tiegang Liu A. W. Chowdhury & Boo Cheong Khoo 《advances in applied mathematics and mechanics.》2011,3(5):611-632
In this work, the modified ghost fluid method is developed to deal with
2D compressible fluid interacting with elastic solid in an Euler-Lagrange
coupled system. In applying the modified Ghost Fluid Method to treat the
fluid-elastic solid coupling, the Navier equations for elastic solid are
cast into a system similar to the Euler equations but in Lagrangian coordinates.
Furthermore, to take into account the influence of material deformation and
nonlinear wave interaction at the interface, an Euler-Lagrange Riemann problem
is constructed and solved approximately along the normal direction of the
interface to predict the interfacial status and then define the ghost fluid
and ghost solid states. Numerical tests are presented to verify the resultant
method. 相似文献
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Since the (original) ghost fluid method (OGFM) was proposed by Fedkiw et al. in 1999 [5], a series of other GFM-based methods such as the gas–water version GFM (GWGFM), the modified GFM (MGFM) and the real GFM (RGFM) have been developed subsequently. Systematic analysis, however, has yet to be carried out for the various GFMs on their accuracies and conservation errors. In this paper, we develop a technique to rigorously analyze the accuracies and conservation errors of these different GFMs when applied to the multi-medium Riemann problem with a general equation of state (EOS). By analyzing and comparing the interfacial state provided by each GFM to the exact one of the original multi-medium Riemann problem, we show that the accuracy of interfacial treatment can achieve “third-order accuracy” in the sense of comparing to the exact solution of the original mutli-medium Riemann problem for the MGFM and the RGFM, while it is of at most “first-order accuracy” for the OGFM and the GWGFM when the interface approach is actually near in balance. Similar conclusions are also obtained in association with the local conservation errors. A special test method is exploited to validate these theoretical conclusions from the numerical viewpoint. 相似文献
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The modified ghost fluid method (MGFM) provides a robust and
efficient interface treatment for various multi-medium flow
simulations and some particular fluid-structure interaction (FSI)
simulations. However, this methodology for one specific class of FSI
problems, where the structure is plate, remains to be developed.
This work is devoted to extending the MGFM to treat compressible
fluid coupled with a thin elastic plate. In order to take into account
the influence of simultaneous interaction at the interface, a
fluid-plate coupling system is constructed at each time step and
solved approximately to predict the interfacial states. Then,
ghost fluid states and plate load can be defined by utilizing
the obtained interfacial states. A type of acceleration strategy in
the coupling process is presented to pursue higher efficiency.
Several one-dimensional examples are used to highlight the utility
of this method over loosely-coupled method and validate the
acceleration techniques. Especially, this method is applied to
compute the underwater explosions (UNDEX) near thin elastic plates.
Evolution of strong shock impacting on the thin elastic plate and
dynamic response of the plate are investigated. Numerical results
disclose that this methodology for treatment of the fluid-plate
coupling indeed works conveniently and accurately for different
structural flexibilities and is capable of efficiently simulating
the processes of UNDEX with the employment of the acceleration
strategy. 相似文献
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多介质流动问题的求解一般是在结构网格上实现,而三角形网格对于复杂计算区域具有更好的适应性,本文结合rGFM方法,给出三角形网格上多介质流动问题界面处理方法.利用level-set方法跟踪界面,在界面处构造Riemann问题,得到界面处流体准确的流动状态.通过定义界面边界条件,将多介质流动问题转化为单介质流动问题,利用高精度RKDG方法求解.采用多个算例验证该方法的稳健性和有效性,结果表明该方法能准确捕捉界面和激波的位置,保持界面清晰. 相似文献
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Numerical method of the Riemann problem for two-dimensional multi-fluid flows with general equation of state 下载免费PDF全文
Based on the classical Roe method, we develop an interface capture method
according to the general
equation of state, and extend the single-fluid Roe method to the
two-dimensional (2D) multi-fluid flows, as
well as construct the continuous Roe matrix for the whole flow field. The
interface capture equations and
fluid dynamic conservative equations are coupled together and solved by
using any high-resolution
schemes that usually suit for the single-fluid flows. Some numerical
examples are given to illustrate the
solution of 1D and 2D multi-fluid Riemann problems. 相似文献