Hossain Md Mosarraf, Shakher Chandra
Laser Applications and Holography Laboratory, Instrument Design Development Center, Indian Institute of Technology, Delhi, New Delhi-110016, India.
Appl Opt. 2009 Apr 1;48(10):1869-77. doi: 10.1364/ao.48.001869.
A method for measurement of temperature in laminar free convection flow of water is presented using digital holographic interferometry. The method is relatively simple and fast because the method uses lensless Fourier transform digital holography, for which the reconstruction algorithm is simple and fast, and also the method does not require use of any extra experimental efforts as in phase shifting. The quantitative unwrapped phase difference is calculated experimentally from two digital holograms recorded in two different states of water--one in the quiescent state, the other in the laminar free convection. Unknown temperature in laminar free convection is measured quantitatively using a known value of temperature in the quiescent state from the unwrapped phase difference, where the equation by Tilton and Taylor describing the variation of refractive index of water with temperature is used to connect the phase with temperature. Experiments are also performed to visualize the turbulent free convection flow.
提出了一种利用数字全息干涉测量法测量层流自由对流水中温度的方法。该方法相对简单且快速，因为它采用了无透镜傅里叶变换数字全息术，其重建算法简单且快速，并且该方法不像相移法那样需要任何额外的实验操作。通过在水的两种不同状态下记录的两个数字全息图实验计算出定量的展开相位差，一种状态是静止状态，另一种是层流自由对流状态。利用展开相位差，通过静止状态下已知的温度值对层流自由对流中的未知温度进行定量测量，其中使用蒂尔顿和泰勒描述水的折射率随温度变化的方程将相位与温度联系起来。还进行了实验以可视化湍流自由对流。
