POD-analysis of the near field of a turbulent circular jet when mixing gases of different densities
V.A. Ivashchenko1,2, E.V. Palkin1,2, V.O. Ryzhenkov1,2, R.I. Mullyadzhanov1,2
1Kutateladze Institute of Thermophysics SB RAS, Novosibirsk, Russia
2Novosibirsk State University
Keywords: turbulence, jets, direct numerical simulation (DNS), POD
Abstract
A turbulent circular jet with variable density caused by the mixing of air with gases of different densities (air, helium, and carbon dioxide) is studied. The Reynolds number is fixed for all cases: Re = 5300. Using proper orthogonal decomposition and direct numerical simulation data, a comparative analysis of the three gases under consideration is carried out. It is shown that with a decrease in the ambient gas density, the frequency of coherent structures formation drops, and the number of proper orthogonal decomposition (POD) modes necessary for constructing a low-dimensional flow model decreases.
|
