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COMPUTER HYDROMECHANICS, 2024
IX International Scientific & Practical Conference "Computer Hydromechanics"
HYDRODYNAMICS AND ACOUSTICS
2022 ◊ Volume 2 (92) ◊ Issue 3 ◊ p. 300-324
V. G. Kuzmenko*
* Institute of Hydromechanics of NAS of Ukraine, Kyiv, Ukraine
Numerical simulation of separated turbulent flow with suction behind a fence and the energy evolution of three-dimensional coherent structures
Gidrodin. akust. 2022, 2(3):300-324
TEXT LANGUAGE: Ukrainian
ABSTRACT
The unsteady three-dimensional turbulent incompressible flow over a rectangular two-dimensional fence (with suction after fence) in a boundary layer is simulated using hybrid LES/URANS-approach, wall models and finite-difference method. The aspect ratio (height/length) of the fence are 4, fence Reynolds number is Re=10500, inflow Reynolds number is Reδ=10500 for turbulent boundary layer. Behind of fence in zone 17.25<x<79.25 on horizontal wall are placed array of orifices (at every knot of run grid is orifice of circular form d=0.042). Effective orifice suction velocity is constant value (VSL=-0.03) on time interval t={0; 96}. The number of grid points used in the numerical method was 5434455 ({961; 65; 87}). The large-scale coherent structures are identified by the Q-criterion (set of threshold value {Qsi} for total numerical domain). The simulation were performed to study the Q-isosurfaces, integral characteristic of the energy and coherent structure across area under suction. The coherent structures of different configurations were identified in big numerical zone. Powerful effect of constant suction on time interval ({0; 96}) was founded at the configuration of coherent structures. Sizes of coherent structures, theirs characteristics of the energy and coherent structure across areas are decreased consistently and steadfast during time run. Suction during time reduce to high decrease in coherent structure turbulent energy not only in suction zone (17.25<x<79.25), and also near the fence (9<x<12). In zone 20<x<60 on time interval t={0; 48} value of turbulent energy decreases in four times in comparison with variant for without suction (t=0).
KEY WORDS
turbulent boundary layer, fence, numerical method, coherent structures, identification criterion, evolution, suction