A mesh-free framework for high-order direct numerical simulations of combustion in complex geometries
A mesh-free framework for high-order direct numerical simulations of combustion in complex geometries
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DOI：
10.1016/j.cma.2024.116762
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发表时间：
2023-10
影响因子：
7.2
通讯作者：
Jack R. C. King
中科院分区：
文献类型：
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作者：
Jack R. C. King
湍流燃烧的多尺度特性要求采用精确、高效的直接数值模拟方法。长期以来，该领域一直被高阶有限差分所主导，这种有限差分在模拟复杂几何形状和现实环境中火焰-湍流-结构相互作用时缺乏灵活性和适应性。在这项工作中，我介绍了一种新的预混燃烧数值模拟方法，该方法基于高阶无网格离散和有限差分相结合，使得能够在非平凡几何中进行高阶模拟。该方法在一系列二维和三维流动上得到了验证，包括层流和湍流，以及反应和惰性流动。该方法(A)对层流火焰和惰性湍流具有与高阶有限差分相当精度的数值模拟能力，(B)能够捕捉非定常钝体稳定火焰的动力学，(C)能够模拟火焰-湍流相互作用，结果与已发表的数据定性地吻合得很好。这项工作为复杂几何形状的燃烧数值模拟铺平了道路，为基于具有浸没边界的结构网格或非结构网格的方法提供了一种替代方法。对本方法的进一步研究提出了建议，这将有助于理解非平凡几何中的基本火焰动力学。在适应性和将无网格结构扩展到所有三个维度方面的计划发展将增加该方法的价值，并支持推动真实几何的域名系统。
The multiscale nature of turbulent combustion necessitates accurate and computationally efficient methods for direct numerical simulations (DNS). The field has long been dominated by high-order finite differences, which lack the flexibility and adaptivity for simulations of complex geometries and flame-turbulence-structure interactions in realistic settings. In this work I introduce a new approach to DNS of premixed combustion, based on a high-order mesh-free discretisation in combination with finite differences, enabling high-order simulations in non-trivial geometries. The approach is validated against a range of two- and three-dimensional flows, both laminar and turbulent, and reacting and inert. The present method (a) has the resolving power for DNS of both laminar flames and inert turbulence with comparable accuracy to high-order finite differences, (b) can capture the dynamics of unsteady bluff body stabilised flames, and (c) is capable of simulating flame-turbulence interactions, with results comparing qualitatively well with published data. This work paves the way for DNS of combustion in complex geometries, offering an alternative approach to methods based on structured grids with immersed boundaries, or unstructured meshes. Further studies with the present method are proposed, which will aid understanding of fundamental flame dynamics in non-trivial geometries. Planned developments in adaptivity and extension of the mesh-free construction to all three dimensions will increase the value of the method, and support the push towards DNS of real geometries.