论文标题
保护法律和对流扩散方程的非振荡限时整合
Non-Oscillatory Limited-Time Integration for Conservation Laws and Convection-Diffusion Equations
论文作者
论文摘要
在这项研究中,我们考虑了基于时间限制者进行无条件的,高阶的隐式时间。我们工作的第一个方面是在方法框架中提出有关保护法和对流扩散方程的高分辨率有限dirk3(L-DIRK3)方案。该方案可以与任意高阶空间离散方案(例如第五阶WENO方案)结合使用。可以证明,强烈的S稳定DIRK3方案不是SSP,并且可能在很大的时间步骤下引入强振荡。为了克服DIRK3的振荡性,L-DIRK3方案的关键思想是应用局部时间限制者(K.Duraisamy,J.D.Baeder,j-g Liu),在该区域中,局部时间的准确性顺序局部落在本地的第一顺序中,该区域的进化溶液不平稳。这样,单调性条件在局部满足,而在大多数解决方案域中仍然保持高准确性。为了方便地应用方程式系统,我们提出了一个新的简单构建时间限制者,该构建可以通过最小的计算成本灵活地选择参考数量。我们工作的另一个关键方面是将时间限制者方案的应用扩展到多维问题和对流扩散方程。一维和二维方程的标量/方程系统的数值实验证实了在大时段下L-DIRK3的高分辨率和提高的稳定性。此外,结果表明,时间限制者方案的潜力是提高任意DIRK方法稳定性的通用和方便方法。
In this study we consider unconditionally non-oscillatory, high order implicit time marching based on time-limiters. The first aspect of our work is to propose the high resolution Limited-DIRK3 (L-DIRK3) scheme for conservation laws and convection-diffusion equations in the method-of-lines framework. The scheme can be used in conjunction with an arbitrary high order spatial discretization scheme such as 5th order WENO scheme. It can be shown that the strongly S-stable DIRK3 scheme is not SSP and may introduce strong oscillations under large time step. To overcome the oscillatory nature of DIRK3, the key idea of L-DIRK3 scheme is to apply local time-limiters (K.Duraisamy, J.D.Baeder, J-G Liu), with which the order of accuracy in time is locally dropped to first order in the regions where the evolution of solution is not smooth. In this way, the monotonicity condition is locally satisfied, while a high order of accuracy is still maintained in most of the solution domain. For convenience of applications to systems of equations, we propose a new and simple construction of time-limiters which allows flexible choice of reference quantity with minimal computation cost. Another key aspect of our work is to extend the application of time-limiter schemes to multidimensional problems and convection-diffusion equations. Numerical experiments for scalar/systems of equations in one- and two-dimensions confirm the high resolution and the improved stability of L-DIRK3 under large time steps. Moreover, the results indicate the potential of time-limiter schemes to serve as a generic and convenient methodology to improve the stability of arbitrary DIRK methods.