Fully-coupled pressure-based algorithm for compressible flows: Linearisation and iterative solution strategies
Fully-coupled pressure-based algorithm for compressible flows: Linearisation and iterative solution strategies
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DOI：
10.1016/j.compfluid.2018.07.005
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发表时间：
2018-07
影响因子：
2.8
通讯作者：
Fabian Denner
中科院分区：
文献类型：
--
作者：
Fabian Denner
不同的线性化和迭代求解策略的影响完全耦合的压力为基础的算法在所有速度的可压缩流的研究，其目的是阐明其对数值算法的性能的影响。一个固定系数的线性化和牛顿线性化的瞬态和对流项的非线性方程进行了比较，侧重于测试的情况下，功能声波，冲击波和膨胀波。线性化和迭代求解策略应用于离散和解决非线性控制方程的数值算法的性能和稳定性有显着的影响。牛顿线性化的动量和能量方程的瞬态项的迭代求解算法相比，固定系数线性化产生显着改善的收敛性，而线性化的平流项导致在大马赫数和大柯朗数的性能和稳定性的显着差异。它进一步表明，一致的牛顿线性化的所有瞬态和对流项的控制方程允许，在上下文中的耦合压力为基础的算法，以消除所有形式的欠松弛，并提供了一个明确的性能优势，在所有马赫数制度的流动。
The impact of different linearisation and iterative solution strategies for fully-coupled pressure-based algorithms for compressible flows at all speeds is studied, with the aim of elucidating their impact on the performance of the numerical algorithm. A fixed-coefficient linearisation and a Newton linearisation of the transient and advection terms of the governing nonlinear equations are compared, focusing on test-cases that feature acoustic, shock and expansion waves. The linearisation and iterative solution strategy applied to discretise and solve the nonlinear governing equations is found to have a significant influence on the performance and stability of the numerical algorithm. The Newton linearisation of the transient terms of the momentum and energy equations is shown to yield a significantly improved convergence of the iterative solution algorithm compared to a fixed-coefficient linearisation, while the linearisation of the advection terms leads to substantial differences in performance and stability at large Mach numbers and large Courant numbers. It is further shown that the consistent Newton linearisation of all transient and advection terms of the governing equations allows, in the context of coupled pressure-based algorithms, to eliminate all forms of underrelaxation and provides a clear performance benefit for flows in all Mach number regimes.