Stereoscopic PIV on multiple color-coded light sheets and its application to axial flow in flapping robotic insect wings
Stereoscopic PIV on multiple color-coded light sheets and its application to axial flow in flapping robotic insect wings
复制标题
DOI：
10.1007/s00348-009-0687-5
复制
发表时间：
2009-06
影响因子：
2.4
通讯作者：
S. Pick;F. Lehmann
中科院分区：
文献类型：
--
作者：
S. Pick;F. Lehmann
非扫描体积流量测量技术，如3D-PTV、全息和层析粒子图像测速（PIV），允许重建流体体积（3D）中速度和涡度矢量的所有三个分量（3C）。在这项研究中，我们提出了一种新的3D 3C技术称为多色平面立体粒子图像测速（彩色PIV），它允许在六个平行的，彩色光片的3C速度矢量的瞬时测量。我们通过两个选通的白色光通过二向色滤光片产生光片，并通过两个3CCD彩色相机在Stereo-PIV配置中成像切片。通过定制软件程序处理立体彩色图像，该软件程序根据其色调、饱和度和亮度将每个彩色流体颗粒分类到六个灰度图像中的一个。我们使用传统的立体PIV互相关算法来计算每个光片的3D平面矢量场，随后从六个矢量场内插体积流图。作为第一个应用程序，我们量化的机器人昆虫（果蝇）模型机翼的涡结构中的尾流和轴向流。与以前的研究结果相反，测量数据表明在机翼上表面有很强的轴向流分量，包括前缘涡核中的轴向流。总的来说，彩色PIV对机械失准具有强大的鲁棒性，避免了激光安全问题，并在其他3D系统典型时间的一小部分内计算瞬时3D矢量场。因此，彩色PIV对于高度不稳定流的体积测量可能是有价值的。
Non-scanning volume flow measurement techniques such as 3D-PTV, holographic and tomographic particle image velocimetry (PIV) permit reconstructions of all three components (3C) of velocity and vorticity vectors in a fluid volume (3D). In this study, we present a novel 3D3C technique termed Multiple-Color-Plane Stereo Particle-Image-Velocimetry (color PIV), which allows instantaneous measurements of 3C velocity vectors in six parallel, colored light sheets. We generated the light sheets by passing white light of two strobes through dichroic color filters and imaged the slices by two 3CCD color cameras in Stereo-PIV configuration. The stereo-color images were processed by custom software routines that sorted each colored fluid particle into one of six gray-scale images according to its hue, saturation, and luminance. We used conventional Stereo PIV cross-correlation algorithms to compute a 3D planar vector field for each light sheet and subsequently interpolated a volume flow map from the six vector fields. As a first application, we quantified the wake and axial flow in the vortical structures of a robotic insect (fruit fly) model wing. In contrast to previous findings, the measured data indicate strong axial flow components on the upper wing surface, including axial flow in the leading-edge vortex core. Collectively, color PIV is robust against mechanical misalignments, avoids laser safety issues, and computes instantaneous 3D vector fields in a fraction of the time typical for other 3D systems. Color PIV might thus be of value for volume measurements of highly unsteady flows.