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arXiv 2104.09767math.NAcs.NA
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二维可压Navier-斯托克斯方程的一种新的带界面修正的直接间断Galerkin方法

A new direct discontinuous Galerkin method with interface correction for two-dimensional compressible Navier-Stokes equations

Mustafa E. Danis, Jue Yan

摘要:

提出了一个新的非线性粘性数值通量公式,推广了Liu和Yan(H。Liu,J. Yan,The direct discontinuous Galerkin(DDG)method for diffusion with interface corrections,Communications in Computational Physics 8(3)(2010)541)to compressable Navier-斯托克斯方程.新的DDGIC框架是基于这样的观察,即非线性扩散可以表示为对应于每个保守变量的多个单独的扩散过程的总和。定义了一组与每个扩散过程相对应的方向向量,并通过单元界面处的数值解的平均值来近似。新的框架只需要计算守恒变量的梯度,它是线性的,并由原来的直接DG数值通量公式近似。所提出的方法大大简化了实现,因此,可以很容易地扩展到一般方程和湍流模型。用$P_1$、$P_2$、$P_3$和$P_4$多项式逼近的数值实验验证了该方法的最优$(k+1)^{th}$高阶精度。新的DDGIC方法被证明是能够准确地计算物理量,如升力,阻力,摩擦系数以及分离角和Strouhal数。

英文摘要:

We propose a new formula for the nonlinear viscous numerical flux and extend the direct discontinuous Galerkin method with interface correction (DDGIC) of Liu and Yan (H. Liu, J. Yan, The direct discontinuous Galerkin (DDG) method for diffusion with interface corrections, Communications in Computational Physics 8 (3) (2010) 541) to compressible Navier-Stokes equations. The new DDGIC framework is based on the observation that the nonlinear diffusion can be represented as a sum of multiple individual diffusion processes corresponding to each conserved variable. A set of direction vectors corresponding to each individual diffusion process is defined and approximated by the average value of the numerical solution at the cell interfaces. The new framework only requires the computation of conserved variables' gradient, which is linear and approximated by the original direct DG numerical flux formula. The proposed method greatly simplifies the implementation, and thus, can be easily extended to general equations and turbulence models. Numerical experiments with $P_1$, $P_2$, $P_3$ and $P_4$ polynomial approximations are performed to verify the optimal $(k+1)^{th}$ high-order accuracy of the method. The new DDGIC method is shown to be able to accurately calculate physical quantities such as lift, drag, and friction coefficients as well as separation angle and Strouhal number.

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