6. Physics of a Fluid, Neutral and Ionized Gases

ON HELICAL STRUCTURES IN A ROUND TURBULENT JET

Rustam I. Mullyadzhanov
1. Novosibirsk State University Novosibirsk, Russian Federation
2. Institute of Thermophysics SB RAS Novosibirsk, Russian Federation
rustammul@gmail.com
Richard D. Sandberg
1. University of Melbourne Victoria 3010, Australia
Sergey S. Abdurakipov
1. Institute of Thermophysics SB RAS Novosibirsk, Russian Federation
2. Novosibirsk State University Novosibirsk, Russian Federation
s.s.abdurakipov@gmail.com
The material was received by the Editorial Board: 03.09.2017
Using Direct Numerical Simulation (DNS) database we performed a statistical analysis of the characteristics of coherent structures in a turbulent circular pipe jet for Reynolds number Re = 5940 at a distance up to 40 pipe diameters from an inlet. It was shown that the optimal basic functions of the Proper Orthogonal Decomposition of velocity fields have the form of spiral perturbations and correspond to the coherent vortex structures present from the near to far field of the jet. The first two mirror-symmetric POD modes containing about 5 % of the total turbulent kinetic energy describe the spatial structure and dynamics of large-scale velocity fluctuations of the first azimuthal mode m = 1 in the mixing layer of turbulent jet.

Keywords:
turbulent jet, direct numerical simulation, coherent structures.
УДК 532.517.4

ON HELICAL STRUCTURES IN A ROUND TURBULENT JET
References: Mullyadzhanov R. I., Sandberg R. D., Abdurakipov S. S., George W. K., Hanjalic K. ON HELICAL STRUCTURES IN A ROUND TURBULENT JET. Siberian Journal of Physics . 2017, vol. 12, no. 4. P. 40–50. (in Russ.). DOI: 10.25205/2541-9447-2017-12-4-40-50