基于物理信息神经网络的翼型自适应网格加密

Adaptive Mesh Refinement for Airfoil Based on Physics-informed Neural Networks

  • 摘要: 本文利用物理信息神经网络(PINNs)对传统的自适应网格加密方法(AMR)进行扩展,将描述不可压缩流动的Navier-Stokes方程残差作为细化指标来指导非结构三角形网格加密。首先通过传统有限体积法求解粗网格对应的流场,其次提取网格上的流场数据并融合物理信息训练PINNs,利用训练好的模型预测粗网格每个单元中心的方程残差,挑选出固定数目且中心残差较大的网格单元,最后采用基于网格单元最大面积约束的Delaunay三角化算法对其细化。循环以上步骤对网格进行加密,直至所关注的物理量随着网格数目趋于收敛。在雷诺数为1000的不可压缩翼型绕流场景中,与Fluent中的传统AMR框架相比,采用本框架优化得到的升阻力系数与参考解吻合良好,且大幅减少了细化后最优网格的单元数量。

     

    Abstract: This paper adopts an extension of the traditional adaptive mesh refinement (AMR) method, speeifically combining physics-informed neural networks (PINNs) with the residuals of the Navier-Stokes equations, which describe incompressible fluids as the refinement metric, to guide the refinement of unstructured triangular meshes. We first solve the flow field corresponding to a coarse mesh by the traditional finite volume method, and then integrate the flow field data from the physical model to train PINNs. The trained model is used to predict the residuals of the Navier-Stokes equations at the center of the coarse mesh cells, and a fixed number of mesh cells with the largest residuals are selected, which are refined using the Delaunay refinement algorithm based on the constraint of the maximum area of the mesh cells. The mesh is refined by repeating the above steps cyclically until the physical quantity of interest converges with the number of meshes. In the incompressible airfoil flow scenario with Re=1000, compared to the traditional AMR framework in Fluent, the lift-drag coefficients obtained from the optimization of this framework are in good agreement with the reference solution, but the number of optimal mesh cells after refinement is significantly reduced.

     

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