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摘要:
随着机器学习的快速发展和其突出的非线性映射能力,越来越多的学者将机器学习方法应用到流体力学领域。为克服传统数学拟合不能很好的解决系统非线性问题,以及现有文献中所提及的一些基于神经网络的气动参数预测方法,需要进行参数化处理而带来的不便,同时为实现多变量多输出气动参数快速预测的目的,基于卷积神经网络考虑机翼变迎角和浮沉建立了一种多变量多输出的机翼气动参数预测模型,实现了机翼气动参数的快速预测。结果表明:所建模型具有较高且稳定的预测精度,并且计算效率较计算流体力学(CFD)提高了40倍。
Abstract:With the rapid development of machine learning and its outstanding nonlinear mapping ability, more and more scholars apply machine learning methods to the field of fluid mechanics. To overcome the obstacle that the traditional mathematical fitting cannot well present the system nonlinearity and the inconvenience of some neural network-based aerodynamic parameter prediction methods due to the need of parametric processing, and to achieve the multi-variable and multi-output aerodynamic parameters, this paper establishes a multi-variable and multi-output model based on convolutional neural network considering the variable angle of attack and the heave of the wing to realize the rapid prediction of the aerodynamic coefficient of the wing. The results show that this model has high prediction accuracy and its computational efficiency is 40 times higher than computational fluid dynamics (CFD). Moreover, the designed stability experiment results show that the proposed model has good stability.
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表 1 差积神经网络具体结构和参数设置
Table 1. Specific structure and parameter setting of CNN
层名称 参数 输入层 机翼状态改变后的原始图像(200×200×3) 卷积层1 卷积核(5×5×96)+relu 池化层1 滤波器大小(3×3)strides(步长)=2 卷积层2 卷积核(3×3×96)+relu 池化层2 滤波器大小(3×3)strides(步长)=2 卷积层3 卷积核(3×3×128)+relu 池化层3 滤波器大小(3×3)strides(步长)=2 全连接层(并列2个) relu+dropout 输出层(并列2个) 激活函数tanh -
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