ISSN 2079-3537      

 
 
 
                                                                                                                                                                                                                                                                                                                                                                                                                                                                             
Scientific Visualization
Issue Year: 2013
Quarter: 3
Volume: 5
Number: 3
Pages: 17 - 39
Article Name: EXPERIMENTAL RESEARCH AND COMPUTER MODELING OF REFRACTION OF THE PLANE-STRUCTURED LASER BEAM IN OPTICAL INHOMOGENEOUS MEDIUM
Authors: M. Kuzmicheva (Russian Federation), I. Raskovskaya (Russian Federation), B. Rinkevichyus (Russian Federation)
  The paper is recommended by program committee of 12th International Conference OMFI 2013 (Optical Methods of Flow Investigations).
Address: M. Kuzmicheva
m_s_h@mail.ru
National Research University MEI, Moscow, Russian Federation
 
I. Raskovskaya
raskovskail@mail.ru
National Research University MEI, Moscow, Russian Federation
 
B. Rinkevichyus
rinkevbs@mail.ru
National Research University MEI, Moscow, Russian Federation
Abstract: For experimental research of physical processes in liquids and gases can be used the method of laser refractography, consisting in probe the medium of interest with structured laser radiation, record the radiation passing through the medium with a CCD camera, and process with the aid of a computer the refraction patterns processing with a view to finding out the properties of the medium. The method of visualization and quantitative diagnostics of optically transparent inhomogeneous medium, based on the phenomenon of refraction plane structured laser radiation, is the most commonly used.
The mathematical modeling of the refraction patterns (refractograms) obtained by probing the medium under study with a structured laser radiation is fundamental to the quantitative diagnostics of the medium.
The development of specialized quantities algorithms for constructing a ray trajectory of structured radiation within the laws of geometrical optics is actual in general case of diagnostics of volume three-dimensional inhomogeneities of the refractive index in a strong refraction conditions. In the paper the results of implementation of such algorithm have been presented and ray trajectories of plane beam have been visualized in inhomogeneous mediums of different types (3D-refractograms).
However, where complex ray patterns are present or caustic surfaces are formed in the medium, or elsewhere diffraction effects must be taken into consideration, the geometrical-optics approach proves inconsistent, and so use should be made of wave methods. For this reason, a wave-equation-based refractograms processing algorithm has been developed. In the paper the results of a quantitave algorithm for computing the Kirchhoff integral presented and 2D-refractograms of plane beam in the inhomogeneous mediums of different types: thermal water inhomogeneity, and the diffusion layer in the salt stratified medium visualized.
The refroctographic schemes of computer-laser systems and the results of the experimental visualization of 2D and 3D-refractograms plane beam to visualize the near-wall thermal processes in the water have been shown. The results of quantitative diagnostics near-wall temperature surface in the water layer and the diffusion layer in salt stratified liquid have been shown. If there is a theoretical model of the process the using digital methods of recording and processing refractograms allows us to solve the inverse problem of recovering the profile of the inhomogeneity of temperature or concentration, and realize quantitative diagnostics of inhomogeneous medium in parallel with its visualization.
Developed technique of experimental visualization of structured laser radiation can be used for monitoring the thermal processes in the liquid, gas and plasma, convection in the liquid around the heated or cooled bodies, quantitative diagnostics of concentration and temperature fields in the boundary layer, process of mixing various liquids in devices of Chemical Technology, diagnosis stratified liquids, acoustic fields and other physical processes that affect the value of the refractive index.
Language: Russian