本文系统地慨述了近年来激光测雾技术的发展，介绍了激光多谱勒测速技术、粒子图象测速技术、激光散射技术、激光全息技术、激光荧光法以及激光衰减法的原理、特点和存在的一些问题，并指出了激光测试技术在燃油喷雾研究中的应用前景。

结合三光束激光多普勒测速仪，从理论上分析了在不同介质中测量参数的修正，推导出LDA在不同介质中的参数修正公式。以空气和水两种不同介质为例，利用修正公式求出各自的参数,在二维流道上用LDA测量减阻流体的流速，将LDA与流量计的测量结果进行比较，结果令人满意。

A real time nondestructive temperature measurement technique based on laser holographic interference tomography technique is presented. An He-Ne laser is used as light source, and a CCD video camera is used to grab the interferogram. This laser holographic tomography technique is applied to the measurement of the temperature fields generated by two heated rods. Since data error is inevitable in engineering measurement, it is necessary to study the reconstruction techniques for reconstructing the temperature field. Three techniques including convolution back projection (CBP), algebra reconstruction technique (ART) and simultaneous iterative reconstruction technique (SIRT) are studied. Based on the reconstruction techniques and experimental situation, ART is used to reconstruct the asymmetric temperature fields. The thermocouples are used to measure the temperatures of the two heated rods. Comparing the reconstructed result with the measured temperature value, a satisfactory result is obtained.

Drag reduction of turbulent water flow with surfactant (CTAC) additives was experimentally investigated. By using PIV and PDA measurements, the spatial velocity distribution of surfactant solution flow was clarified in a two-dimensional water channel. With an increasing Reynolds number, it was found that drag reduction of surfactant solution flow is enhanced within the region of drag reduction. However, in the region of post drag reduction, the drag-reducing coefficient approaches one without surfactant when Reynolds number is increased. In the near-wall region, velocity profiles of the drag-reducing fluid are similar to, but not the same as, the laminar profiles of the Newtonian fluid. When compared to the case of water flow without surfactant, the velocity contour lines of the drag-reducing fluid run approximately parallel to the wall.

The mechanism of turbulent heat transfer in the thermal boundary layer developing in the channel flow of a drag-reducing surfactant solution was studied experimentally. A twocomponent laser Doppler velocimeter and a fine-wire thermocouple probe were used to measure the velocity and temperature fluctuations simultaneously. Two layers of thermal field were found: a high heat resistance layer with a high temperature gradient, and a layer with a small or even zero gradient. The peak value of -u+θ+was larger for the flow with the drag-reducing additives than for the Newtonian flow, and the peak location was away from the wall. The profile of -u+θ+was depressed in a similar manner to the depression of the profile of -u+θ+ in the flow of the surfactant solution, i.e., decorrelation between v and θcompared with decorrelation between u and v. The depression of the Reynolds shear stress resulted in drag reduction; similarly, it was conjectured that the heat transfer reduction is due to the decrease in the turbulent heat flux in the wall-normal direction for a flow with dragreducing surfactant additives.