Martínez-González A, Moreno-Hernández D, Guerrero-Viramontes J A
Centro de Investigaciones en Óptica A.C., León, Guanajuato, Mexico.
Appl Opt. 2013 Aug 1;52(22):5562-9. doi: 10.1364/AO.52.005562.
A convective fluid flow in air could be regulated if the physical process were better understood. Temperature and velocity measurements are required in order to obtain a proper characterization of a convective fluid flow. In this study, we show that a classical schlieren system can be used for simultaneous measurements of temperature and velocity in a convective fluid flow in air. The schlieren technique allows measurement of the average fluid temperature and velocity integrated in the direction of the test beam. Therefore, in our experiments we considered surfaces with isothermal conditions. Temperature measurements are made by relating the intensity level of each pixel in a schlieren image to the corresponding knife-edge position measured at the exit focal plane of the schlieren system. The same schlieren images were also used to measure the velocity of the fluid flow by using optical flow techniques. The algorithm implemented analyzes motion between consecutive schlieren frames to obtain a tracked sequence and finally velocity fields. The proposed technique was applied to measure the temperature and velocity fields in natural convection of air due to unconfined and confined heated rectangular plates.
如果能更好地理解物理过程，那么空气中的对流流体流动就可以得到调节。为了恰当地描述对流流体流动，需要进行温度和速度测量。在本研究中，我们表明经典纹影系统可用于同时测量空气中对流流体流动的温度和速度。纹影技术允许测量在测试光束方向上积分的平均流体温度和速度。因此，在我们的实验中，我们考虑了等温条件的表面。通过将纹影图像中每个像素的强度水平与在纹影系统出射焦平面处测量的相应刀口位置相关联来进行温度测量。同样的纹影图像也用于通过光流技术测量流体流动的速度。所实现的算法分析连续纹影帧之间的运动以获得跟踪序列并最终得到速度场。所提出的技术被应用于测量由于无约束和有约束的加热矩形板引起的空气自然对流中的温度和速度场。
