Variational Multiscale based dissipation models for the estimation of atmospheric seeing. (31st January 2015)

• Record Type: Journal Article
• Authors: Baiges, Joan; Codina, Ramon
• Is Part Of: Computers & fluids. Volume 107(2015)
• Page Start: 141
• Page End: 154
• Publication Date: 2015-01-31
• Subjects: Atmospheric seeing -- Numerical simulation -- Finite elements -- Large-Eddy Simulation -- Variational Multiscale -- Telescopes; Fluid dynamics -- Data processing -- Periodicals; 532.050285
• DOI: 10.1016/j.compfluid.2014.10.010
• Languages: English
• ISSNs: 0045-7930

Abstract

Highlights: We develop a new model for the estimation of atmospheric seeing parameters. The refraction index structure function is computed from the numerical dissipations. Numerical dissipations are computed from stabilization terms which model turbulence. The new model is applied to the estimation of seeing for atmospheric problems. Results are compared with the Smagorinsky model. Abstract: In this work we present a numerical model for the estimation of atmospheric seeing in observation sites. The particularity of the method is that it is based on a Variational Multiscale turbulence model, its main feature being that the numerical mechanisms which are used to deal with stability issues (convection and the inf–sup condition for incompressible flows) do also take care of the modeling of turbulence. Based on this turbulence model, we develop the expressions for the viscous and thermal dissipations, ∊ num and χ num, which are later used for evaluating the constant of structure of the refraction index C n 2 following the classical model developed by Tatarski. Numerical examples show the behavior of the proposed numerical scheme when applied to turbulent flow practical cases, which include a convective boundary layer, the flow inside a transfer optics room, and a telescope enclosure.