Spatially adaptive PIV interrogation based on data ensemble
Spatially adaptive PIV interrogation based on data ensemble
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DOI：
10.1007/s00348-009-0782-7
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发表时间：
2010-05
影响因子：
2.4
通讯作者：
R. Theunissen;F. Scarano;M. Riethmuller
中科院分区：
文献类型：
--
作者：
R. Theunissen;F. Scarano;M. Riethmuller
本文提出了一个具体的应用，作者最近提出的方法，以实现一个自主的和强大的自适应的PIV数据集的询问方法，重点是平均速度场的确定。在诸如次优流播分布和速度场特性的大变化的情况下，多重网格技术和基于瞬时条件的标准的自适应询问都不能为流场分析提供足够的鲁棒性。本文提出了一种基于数据集成的自适应询问参数选择方法，即窗口大小、纵横比、方向和重叠因子。询问窗口的大小，形状和空间分布的基础上的平均播种密度和速度矢量场的梯度。与瞬时方法相比，基于系综的标准以更稳健的方式调整窗口，特别是对于非各向同性窗口（拉伸和方向）的实现，这会产生更高的空间分辨率。如果递归地应用该过程，则可以优化相关样本的数量以满足规定的窗口重叠比水平。的相关性和适用性的方法示出的应用程序的冲击波边界层干扰问题。此外，应用于跨音速翼型尾迹的双分辨率实验验证了通过使用非各向同性询问窗口可以提高尾迹的空间分辨率。
This paper proposes a specific application of the approach recently proposed by the authors to achieve an autonomous and robust adaptive interrogation method for PIV data sets with the focus on the determination of mean velocity fields. Under circumstances such as suboptimal flow seeding distribution and large variations in the velocity field properties, neither multigrid techniques nor adaptive interrogation with criteria based on instantaneous conditions offer enough robustness for the flow field analysis. A method based on the data ensemble to select the adaptive interrogation parameters, namely, the window size, aspect ratio, orientation, and overlap factor is followed in this study. Interrogation windows are sized, shaped and spatially distributed on the basis of the average seeding density and the gradient of the velocity vector field. Compared to the instantaneous approach, the ensemble-based criterion adapts the windows in a more robust way especially for the implementation of non-isotropic windows (stretching and orientation), which yields a higher spatial resolution. If the procedure is applied recursively, the number of correlation samples can be optimized to satisfy a prescribed level of window overlap ratio. The relevance and applicability of the method are illustrated by an application to a shock-wave-boundary layer interaction problem. Furthermore, the application to a transonic airfoil wake verifies by means of a dual-resolution experiment that the spatial resolution in the wake can be increased by using non-isotropic interrogation windows.