Exploitable results Development of optical techniques for the measurement of velocity and temperature in turbulent flows A universal setup for the study of subsonic air and water flows has been designed and manufactured. Software and technique for temperature measurement have been developed using LC thermography and digital processing of true colour images. Advanced LCT technique has been successfully applied for the measurement of temperature fields on a corrugated surface. The constants of thermal inertia of LC temperature sensors have been investigated. It has been obtained that LC detector allows one to study the processes with unsteadiness times of about 0.02-0.04 s. in water medium. PIV technique developed in Edinburgh University has been integrated with existing facilities. Velocity fields were registered by means of the technique. On the basis of a code developed in Edinburgh, software was developed to provide the data processing. Advanced methods PIV and LC thermography were tested in the water channel with standing wave. The results of combined measurements of velocity and temperature provided valuable information in researches of turbulent flows. In Moscow, the fibre optics probes were manufactured. These probes are intended for investigation of two-phase turbulent flows and acoustic fields in a gas or a liquid. The experimental study of the Doppler signal parameters dependence on the dual beam LDA optics features for large particles. It is shown that Doppler signal frequency depends on a scattered light observation angle. This dependence results from a nonlinear variation of the phase of scattered wave at particle transit through a Gaussian beam. The experimental setup was designed and investigations of acoustic field using Doppler technique were carried out. In Minsk, experiments with ST reconstruction of 3D temperature fields in a turbulent flows were performed. A high repetition rate Cu-vapour laser and single-pulse Q-switched ruby laser have been used as radiation sources. As a result, the 3D temperature field in an open turbulent four-jet propane flame was reconstructed with the help of Radon integral transform on the base of twelve projection speckle photographs. The obtained temperature distributions has rather high spatial frequencies. This illustrates the relatively high spatial resolution attained in these experiments. The results obtained demonstrate that the tomography approach extends the applicability of speckle photography to the measurement of 3D fields even in turbulent flows. As demonstrated, the Double Exposure Speckle Photography, DESP, scheme can be used as a basis for multi-directional tomographic temperature measurements for the temperature range T 1000K. With a limited number of projections (N 12), only large scale turbulent vortices can be determined by ST. The influence of the very small vorticity on the reconstruction accuracy is the subject of the future investigations. The SPESP technique was used here both in frame and streak recording mode. As in streak mode for high speed photography, a slit is installed to record a time history of a single exposure speckle pattern along selected line in the flow studied. Individual speckles in this mode will form on the moving film, streaks with different thickness, similar to interferometric fringes. This thickness at a chosen film position will be determined by the intensity of density (temperature) fluctuations at a chosen instant of time. In frame mode SPESP gives more information then DESP about turbulence parameters of the flow under study. Under this project, the whole field of the intensity of temperature fluctuations in a turbulent flame was measured by SPESP. It is shown that in some flow regions the fluctuations are dependent on direction. The value and direction of turbulence anisotropy was quantitatively measured and 2D maps of the turbulence anisotropy are derived. Searching for OpenAIRE data... There was an error trying to search data from OpenAIRE No results available
