基于物理约束深度学习的大跨柔性光伏阵列绕流场重构

Reconstruction of flow fields around large-span flexible PV array based on physics-informed deep learning

  • 摘要: 大跨柔性光伏阵列双向串联结构引起的排间复杂三维绕流效应是导致其发生风致破坏的重要原因之一,传统物理风洞试验很难直接捕捉到排间干扰下流场流动全过程的分布特性,深度学习方法为实现其复杂流场的精确重构与预测提供了新思路。以国电投江苏盐城柔性光伏示范基地40 m跨度五排三跨光伏阵列为研究对象,开展了大跨柔性光伏阵列脉动风场大涡模拟,在此基础上提出了一种损失函数嵌入N-S方程和连续性方程约束的全连接神经网络深度学习方法,建立了重构大跨柔性光伏阵列绕流场的数据驱动模型和数据-物理双驱动模型,实现了大跨柔性光伏阵列速度和压力绕流场的准确重构。结果表明:相比于数据驱动模型,数据-物理双驱动模型更加精确地捕捉到了大跨柔性光伏阵列绕流场流动特征,其中前两排及第四排光伏板后侧、光伏板上下缘及尾流区流向速度重构误差分别降低了60.2%和36.6%,光伏板上下缘横向速度重构误差降低了53.7%,流向速度和横向速度的全场重构误差分别为16.6%和18.5%;同时,损失函数缺乏压力项时,数据驱动模型无法从训练数据中捕捉压力信息,而数据-物理双驱动模型中的N-S方程和连续性方程引导模型通过速度场信息求解压力场,排间绕流区压力场平均重构误差仅为16.1%。本文研究为风荷载作用下复杂结构绕流场智能重构新方法提供了参考。

     

    Abstract: The complex three-dimensional inter-row flow interference induced by bidirectional series of large-span flexible PV arrays is the primary reason for the wind-induced damage. However, wind tunnel tests are difficult to capture the flow fields subjected to inter-row interference. By comparison, deep learning methods offer promising solutions for accurate reconstruction and prediction of complex flow fields. The present study focuses on the 5-row by 3-span PV array with a span of 40 meters, located at the State Power Investment Group Flexible PV Demonstration Base in Yancheng, Jiangsu. Large-eddy simulations of wind fields were performed to provide training data for a fully connected neural network deep learning method that incorporates the loss function into Navier-Stokes equations. Based on this innovative method, a data-driven model and a data-physics-driven model are established for accurately reconstructing the velocity and pressure fields around an array of large-span flexible PV. Compared to the data-driven model, the data-physics-driven model demonstrates superior efficacy in capturing the flow characteristics. Specifically, the streamwise velocity reconstruction errors upstream of the first two rows and the fourth row, at the upper and lower edges of the PV panels and in the wake region are reduced by 60.2% and 36.6%, respectively. The reconstruction errors of the lateral velocity at the upper and lower edges of the PV panels are reduced by 53.7%. Moreover, the model has full-field reconstruction errors of 16.6% and 18.5% for the streamwise and lateral velocities, respectively. Meanwhile, when the pressure term is not considered in the loss function, the data-driven model cannot learn pressure information from the training data, while the data-physics-driven model can obtain the pressure field through the velocity field, yielding an average reconstruction error of the inter-row pressure fields being only 16.1%. This study provides a reference for a new intelligent reconstruction method for the flow fields around complex structures under wind loads.

     

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