V.A. Banakh, A.A. Sukharev
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, 1, Academician Zuev square, Tomsk, 634021, Russia
Keywords: турель, ударная волна, средняя интенсивность, фокусировка оптического излучения, turret, shock wave, mean intensity, focusing of optical radiation
Subsection: OPTICS OF STOCHASTICALLY-HETEROGENEOUS MEDIA
Results of calculation of the mean intensity of an optical beam crossing a shock wave arising at the supersonic flowing the turret at the beginning of a path in a homogeneous medium are present. It is shown that the spatial inhomogeneity of the refractive index of air in the area occupied by a shock wave can cause strong anisotropic distortions of a beam intersecting a shock wave. The distortions leads to focusing and fragmentation of a beam at relatively small distances from the turret and its quick degradation during further propagation.
The structure of air turbulent motion inside closed volumes (without exchange of internal and external medium through the borders) over inhomogeneously heated underlying surfaces is studied by numerical solution of boundary value problems for hydrodynamics equations (Navier-Stokes). The solitary large vortices (coherent structures, topological solitons) are observed over an inhomogeneously heated surface. Number of vortices and its internal structure depend on the form and size of heated inhomogenities. In the case of simple forms of heating (homogeneous heating, heated single round spot), the coherent turbulence resulting from the decay of coherent vortices is observed inside a closed volume. For complex forms of heating (thermal diversity, dapple, motley), the toroidal vortices are noticeably deformed. The vortices can be extended along the surface and can have the spiral (helix) streamlines. The vortices are noticeably mixed during the evolution process. It leads to Kolmogorov (incoherent) turbulence. Our experimental data obtained earlier inside dome rooms of astronomical telescopes confirm our numerical simulations.
G.I. Gorchako1v1, V.M. Kopeikin1, A.V. Karpov1, A.A. Titov2, D.V. Buntov1, G.A. Kuznetsov1, R.A. Gushchin2, O.I. Dazenko2, G.A. Kurbatov3, A.O. Seregin2, A.V. Sokolov1 1A.M. Obukhov Institute of Atmospheric Physics Russian Academy of Sciences, Pyzhevsky per., 3, 119017, Moscow, Russia 2Moscow State University of Information Technologies, Radio Engineering and Electronics, prospect. Vernadskogo, 78, 119454, Moscow, Russia 3Lomonosov Moscow State University, GSP-1, Leninskie Gory, 1/2, Moscow, 119991, Russia
Keywords: опустынивание, ветропесчаный поток, нелинейные процессы, сальтация, электрический ток сальтации, удельный заряд, эмпирические функции распределения, спектры мощности флуктуаций, desertification, wind sand flux, nonlinear processes, saltation, electric current of saltation, specific charge, empirical function distribution, fluctuation power spectra
Subsection: OPTICS OF CLUSTERS, AEROSOLS, AND HYDROSOLES
First the specific charge probability distribution of the saltating sand over the desertified area has been obtained. The specific charge of the saltating sand was varied between 10 and 150 mC/kg (at the average 48.5 mC/kg) according to the measurement data in Kalmykia over the desertified area. An original setup has been designed whereby the synchronous measurements of the saltating sand concentrations and electric current fluctuations and also the turbulent pulsations of the wind velocity have been carried out over the desertified area in Kalmykia. First transformation pecularities determined by nonlinear processes in the wind sand flux of the statistical characteristics from the wind velocity to the sand grain concentration and further to the electric current of the saltation have been established. In particular, empirical function distributions and fluctuation power spectra were analyzed.
The method of solving the light scattering problem in the backscattering direction within the framework of physical optics approximation has been considered. The recommendations on preliminary estimate of the contribution geometrical optics beams to the backward direction that can reduce the number of the beams for the calculation has been given. Presented empirical estimates and the guidelines for choosing the optimal step of numerical integration can significantly reduce the resource consumption of the physical optics method. The results of the solutions of the light scattering problem are available free in the form of a data bank of the Mueller matrices.
Results of experiments on controlling the position and length of the filamentation zone of femtosecond laser pulses at atmospheric paths 150 m long using different initial spatial focusing and defocusing are presented. The distribution of filaments along the filamentation zone is found, the dependences of the length of the filamentation zone on the numerical aperture of the beam, its initial radius, and pulse power are measured. Emission spectra of the illumination of targets of various materials, placed in the region of the filament far from the radiation source, are recorded.
Microwave (MW) radiometers are commonly used for monitoring precipitable water vapor (PWV) - the major atmospheric greenhouse gas. The quality and accuracy of the method is assessed in various measuring campaigns. In this study, we intercompare the results of PWV measurements performed with a ground-based MW radiometer RPG-HATPRO (at the Peterhof station of Saint Petersburg State University) and radiosounding data obtained at the Voeykovo station. The dataset includes more than 850 coincident measurements (at the day and at the nighttime) for the period between March 13, 2013 and May 31, 2014. The discrepancy of the both methods is caused by the errors of methods as well as by the spatial inhomogeneity of the fields of PWV in atmosphere. These mismatches can reach tens of percent, which must be taken into account in the intercomparison and validation of different methods for PWV retrieval. The exclusion of cases with significant moisture inhomogeneity allowed the reducing of mean errors and their standard deviation between two sets of measurements up to 3-4% and 12-14%, respectively.
The phase-averaged velocity distributions were applied for calculation of parameters of a precessing vortex core; these were the input data for calculation of precession frequency by a formula derived from the helical vortex theory. It was demonstrated that the calculated frequency is within 10% error from the frequency measured in experiments. These results confirm the theory validity, and this opens opportunities for analysis of mechanisms controlling the precessing vortex core and external factors.
The constitutive effect of physical properties of liquid (pressure of saturated vapors and heat of vaporization) and the value of pressure in the vacuum chamber on the behavior of wall liquid film flowing into vacuum was determined experimentally. This behavior is characterized by liquid film rise, disintegration into droplets, and cooling down to freezing.
T. F. GRIGORIEVA1, L. N. DYACHKOVA2, S. V. VOSMERIKOV1, I. A. VORSINA1, S. V. TSYBULYA3, T. A. UDALOVA1 and N. Z. LYAKHOV1 1Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch of the Russian Academy of Sciences, Ul. Kutateladze 18, Novosibirsk 630128 (Russia) E-mail: grig@solid.nsc.ru 2Powder Metallurgy Institute, National Academy of Sciences of Belarus, Ul. Platonova 41, Minsk 220005 (Belarus) 3Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Pr. Akademika Lavrentyeva 5, Novosibirsk 630090 (Russia)
Keywords: tungsten, zirconium, mechanochemical interaction, mechanocomposites, carboxylic acids, poly(N-vinylpyrrolidone)
Pages: 23–28
Mechanocomposites composed of tungsten and zirconiums interacting with the former according to the equilibrium diagram of states were studied. The composition, structure and morphology of the samples obtained at the stages of mechanical activation are considered. The effect of the introduction of organic compounds into W/Zr mechanocomposites is studied.
