Rainbow refractometry is widely used to measure the radius and real part of refractive index of a cylinder. However, studies on the detection of imaginary part of the refractive index with rainbow technique were scarc...Rainbow refractometry is widely used to measure the radius and real part of refractive index of a cylinder. However, studies on the detection of imaginary part of the refractive index with rainbow technique were scarce. This paper presents a new method for simultaneously measuring the radius, real and imaginary part of the refractive index of a cylinder, on the basis of the Airy theory and the Bouguer theory. The rainbows produced by the illuminated cylinder at a capillary exit are captured by a CCD camera in a lab- scale system, and then processed by the proposed method. Experimental results showed that the radius, real and imaginary part of the refractive index can be accurately determined when the SNR （signal to noise ratio） of the ripple structure is sufficiently high. However, the SNR of the ripple structure gradually decreases with decreasing scattering intensity of the cylinder, leading to larger measurement errors of the radius and real part of the refractive index. The relative error of the imaginary part of the refractive index derived from the measurement errors of the radius and real part of the refractive index, is less than 3.4%.展开更多
This paper analyzes the correctly-expanded supersonic jet from a convergent-divergent axisymmetric nozzle by using numerical simulation of turbulent flow.And the calculated density distributions in this flow are compa...This paper analyzes the correctly-expanded supersonic jet from a convergent-divergent axisymmetric nozzle by using numerical simulation of turbulent flow.And the calculated density distributions in this flow are compared with the present experimental data using rainbow schlieren deflectometry.The value of the density from the experimental data agrees well with the results calculated by this simulation.Therefore,the present method of the measurement using rainbow schlieren deflectometry is useful for the measurement of the density of the correctly-expanded supersonic jet.展开更多
基金the National Natural Science Foundation of China(No.50906012)Research Award Program for Outstanding Young Teachers in Southeast University,China(No.3203001202)+2 种基金QingLan Project(No.1103000126)Scientific Research Foundation of Graduate School of Southeast University(YBJJ1220)Research and Innovation Project for College Graduates of Jiangsu Province(CLCX-0106)
文摘Rainbow refractometry is widely used to measure the radius and real part of refractive index of a cylinder. However, studies on the detection of imaginary part of the refractive index with rainbow technique were scarce. This paper presents a new method for simultaneously measuring the radius, real and imaginary part of the refractive index of a cylinder, on the basis of the Airy theory and the Bouguer theory. The rainbows produced by the illuminated cylinder at a capillary exit are captured by a CCD camera in a lab- scale system, and then processed by the proposed method. Experimental results showed that the radius, real and imaginary part of the refractive index can be accurately determined when the SNR （signal to noise ratio） of the ripple structure is sufficiently high. However, the SNR of the ripple structure gradually decreases with decreasing scattering intensity of the cylinder, leading to larger measurement errors of the radius and real part of the refractive index. The relative error of the imaginary part of the refractive index derived from the measurement errors of the radius and real part of the refractive index, is less than 3.4%.
文摘This paper analyzes the correctly-expanded supersonic jet from a convergent-divergent axisymmetric nozzle by using numerical simulation of turbulent flow.And the calculated density distributions in this flow are compared with the present experimental data using rainbow schlieren deflectometry.The value of the density from the experimental data agrees well with the results calculated by this simulation.Therefore,the present method of the measurement using rainbow schlieren deflectometry is useful for the measurement of the density of the correctly-expanded supersonic jet.
