论文标题
使用低马赫数下可压缩的Navier-Stokes方程的高阶光谱元素近似的大涡模拟的子网格秤模型的比较
Comparison of Sub-Grid Scale Models for Large-Eddy Simulation using a High-Order Spectral Element Approximation of the Compressible Navier-Stokes Equations at Low Mach Number
论文作者
论文摘要
这项研究旨在确定使用高阶光谱元素对低MACH压缩流的大型涡流模拟的某些常见(且一些不常见的)子网格量表(SGS)模型的特性,优势和缺点。研究的模型是经典的恒定系数Smagorinsky-Lilly,Vreman的模型和两个动态SGS(DSGS)模型的两个变体,旨在稳定有限和光谱元素,以解决运输占主导地位的问题。特别是,我们比较了一个基于时间依赖的残差版本(R-DSG)的DSG的一种变体,与基于时间无关的残差方案(T-DSG)相比。 Smagorinsky和Lilly的参考模型与参考模型进行了比较:(i)稳定数值解决方案,(ii)最大程度地减少底层和过冲,(iii)捕获/保留不连续性,以及(iv)在不同长度尺度上传递能量。研究这些能力的问题:(1)被动前进的示踪剂,(2)耦合的,非线性的方程式,表现出不连续性,(3)分层气氛中重力驱动的流量,以及(4)同质性,同性恋湍流。所有模型都能够保留急剧的不连续性。 VREMAN和R-DSGS模型还减少了用锋利的梯度的线性和非线性对流解决方案中的不足和过冲。我们的分析表明,对于高阶光谱方法的数值稳定,R-DSG和T-DSGS模型比Vreman和Smagorinsky-Lilly更健壮。 Smagorinsky和Vreman模型能够更好地解决剪切流中更细的流结构,而节点R-DSGS模型显示出更好的能量保护。总体而言,在上面列出的大多数指标中,与其他SGS模型相对于其余的指标,与其他SGS模型相比,R-DSG的淋巴结实现(与其基于元素的对应物相比)被证明超过了其他SGS模型。
This study aims to identify the properties, advantages, and drawbacks of some common (and some less common) sub-grid scale (SGS) models for large eddy simulation of low Mach compressible flows using high order spectral elements. The models investigated are the classical constant coefficient Smagorinsky-Lilly, the model by Vreman and two variants of a dynamic SGS (DSGS) model designed to stabilize finite and spectral elements for transport dominated problems. In particular, we compare one variant of DSGS that is based on a time-dependent residual version (R-DSGS) in contrast to a time-independent residual based scheme (T-DSGS). The SGS models are compared against the reference model by Smagorinsky and Lilly for their ability to: (i) stabilize the numerical solution, (ii) minimize undershoots and overshoots, (iii) capture/preserve discontinuities, and (iv) transfer energy across different length scales. These abilities are investigated on problems for: (1) passively advected tracers, (2) coupled, nonlinear system of equations exhibiting discontinuities, (3) gravity-driven flows in a stratified atmosphere, and (4) homogenous, isotropic turbulence. All models were able to preserve sharp discontinuities. Vreman and the R-DSGS models also reduce the undershoots and overshoots in the solution of linear and non-linear advection with sharp gradients. Our analysis shows that the R-DSGS and T-DSGS models are more robust than Vreman and Smagorinsky-Lilly for numerical stabilization of high-order spectral methods. The Smagorinsky and Vreman models are better able to resolve the finer flow structures in shear flows, while the nodal R-DSGS model shows better energy conservation. Overall, the nodal implementation of R-DSGS (in contrast to its element-based counterpart) is shown to outperform the other SGS models in most metrics listed above, and on par with respect to the remaining ones.