arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1802.00775physics.flu-dyn
收藏

数据驱动的基于物理的流体流场特征提取

Data-Driven, Physics-Based Feature Extraction from Fluid Flow Fields

Carlos Michelén Ströfer, Jinlong Wu, Heng Xiao, Eric Paterson

摘要:

在许多流体动力学应用中,特征识别是一项重要的任务,为此目的已经开发了各种方法。这些方法基于对特征附近的流动的基本行为的物理理解。特别是,它们依赖于定义合适的标准(即基于点或基于邻域的衍生属性)和适当的阈值选择。例如,在其他技术中,涡流识别可以通过计算Q准则或通过考虑循环流线的中心来完成。然而,这些方法依赖于特定特征和流态的物理特性的创造性可视化,使得它们不通用并且需要大量的努力来开发。在这里,我们提出了一个基于物理的,数据驱动的方法,能够识别任何流特征,它是训练。我们使用卷积神经网络,一种为图像识别开发的机器学习方法,并使其适应识别流动特征的问题。用数值模拟得到的平均流场对该方法进行了检验,其中在通过收敛-扩张通道的二维流中识别了回流区和边界层,在机翼-机身连接处的三维流中识别了马蹄涡。该方法的新颖之处在于它能够识别任何类型的特征,甚至区分相似的特征,而不需要明确定义物理学(即通过开发合适的标准和调整阈值)。这提供了一种通用方法,并消除了识别新特征的巨大负担。我们希望这种方法可以补充现有的技术,并允许更自动和更有辨别力的特征检测。该方法可以很容易地扩展到时间相关的流,在那里它可能特别有影响力。

英文摘要:

Feature identification is an important task in many fluid dynamics applications and diverse methods have been developed for this purpose. These methods are based on a physical understanding of the underlying behavior of the flow in the vicinity of the feature. Particularly, they rely on definition of suitable criteria (i.e. point-based or neighborhood-based derived properties) and proper selection of thresholds. For instance, among other techniques, vortex identification can be done through computing the Q-criterion or by considering the center of looping streamlines. However, these methods rely on creative visualization of physical idiosyncrasies of specific features and flow regimes, making them non-universal and requiring significant effort to develop. Here we present a physics-based, data-driven method capable of identifying any flow feature it is trained to. We use convolutional neural networks, a machine learning approach developed for image recognition, and adapt it to the problem of identifying flow features. The method was tested using mean flow fields from numerical simulations, where the recirculation region and boundary layer were identified in a two-dimensional flow through a convergent-divergent channel, and the horseshoe vortex was identified in three-dimensional flow over a wing-body junction. The novelty of the method is its ability to identify any type of feature, even distinguish between similar ones, without the need to explicitly define the physics (i.e. through development of suitable criterion and tunning of threshold). This provides a general method and removes the large burden placed on identifying new features. We expect this method can supplement existing techniques and allow for more automatic and discerning feature detection. The method can be easily extended to time-dependent flows, where it could be particularly impactful.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑