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激波探测器引导的自适应黏性PINN方法研究

RESEARCH ON THE SHOCK DETECTOR-GUIDED ADAPTIVE VISCOSITY PINN METHOD

  • 摘要: 基于参数化方法的可压缩流动快速预测对航空航天领域的气动设计与优化至关重要, 物理信息神经网络(PINN)为此类问题的求解提供了新范式, 但其在求解含激波流动时仍面临激波捕捉失效、数值振荡等挑战. 针对上述问题, 本文提出一种激波探测器引导的自适应黏性PINN方法. 首先构建了“探测-引导-惩罚”的自适应黏性调控机制, 通过激波探测器生成的连续激波指示函数, 实现在激波区域自适应增加耗散提高稳定性, 在光滑区域增强惩罚减小数值耗散. 在此基础上, 引入马赫数分层与损失引导的自适应重采样策略以解决参数空间的学习失衡问题, 并采用4阶段渐进训练框架进行训练. 最后分别通过单楔和三楔进气道算例进行预测精度验证. 结果表明, 该方法无需外部数据, 有效解决了现有PINN方法在求解强间断流场问题中存在的精度与稳定性的问题. 在单楔算例Ma2.0 ~ 3.0参数域内, 激波角预测误差低于0.2°; 在三楔进气道算例中, 物理场平均绝对误差控制在1.0%以内, 激波角预测误差低于0.3°, 且能准确捕捉不同算例下的激波强度与流场结构, 验证了本文方法求解参数化强间断流动问题的有效性和鲁棒性.

     

    Abstract: Rapid prediction of compressible flows based on parametric approaches is critical for aerodynamic design and optimization in aerospace engineering. While physics-informed neural networks (PINNs) provide a novel paradigm for solving such problems, they face significant challenges in handling flows with shock waves, specifically regarding shock capturing failure and numerical oscillations. To address these issues, this paper proposes a shock detector-guided adaptive viscosity PINN method. First, a “detection-guidance-penalization” adaptive viscosity control mechanism is established. By leveraging a continuous shock indicator function generated by a shock detector, this mechanism realizes adaptive dissipation augmentation in shock regions to enhance stability, while intensifying penalization in smooth regions to minimize numerical dissipation. Furthermore, a Mach number-layered and loss-guided adaptive resampling strategy is introduced to resolve learning imbalances within the parameter space, implemented alongside a four-stage progressive training framework. Finally, the prediction accuracy is validated using single-wedge and three-wedge inlet benchmark cases. The results demonstrate that the proposed method, which requires no external data, effectively overcomes the accuracy and stability issues inherent in existing PINN methods for solving strong discontinuity flow problems. In the single-wedge case within the parameter domain of Mach 2.0 to 3.0, the shock angle prediction error remains below 0.2°. For the three-wedge inlet case, the mean absolute error of the physical fields is controlled within 1.0%, and the shock angle prediction error is below 0.3°. The method accurately captures shock strengths and flow field structures under various conditions, verifying its effectiveness and robustness in solving parameterized strong discontinuity flow problems.

     

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