Vol. 28, issue 07, article # 3

Abstract:

Structure of air turbulent motion inside large specialized rooms of astronomical telescopes has been studied by numerical solving of several boundary value problems for hydrodynamics equations (Navier–Stokes). There are optical elements of large-aperture telescopes inside such rooms. The main attention is devoted to closed rooms with different heating the upper and lower surfaces without exchange of internal and external medium through the borders. This enables the testing under steady state conditions of the optical characteristics of astronomical telescopes including their resolution. In particular, a visualization of the air flow motion by streamlines allows one to analyze the impact of design features of telescope and the temperature regime of its optical elements.
Results of our numerical simulations demonstrate that the solitary large vortices (coherent structures, topological solitons) are observed inside specialized rooms. The cascade decay of such vortices leads to the coherent turbulence. The simulations confirm our previously experimentally stated conclusion that the mixing of coherent structures of different close-by sizes (and close-by frequencies of major vortices) results in the non-coherent Kolmogorov turbulence.

Keywords:

turbulence, coherent turbulence, coherent structure, topological soliton, simulation of coherent structures, hydrodynamics equations, Navier–Stokes equations, topological precursor

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