Statistics of the turbulent kinetic energy dissipation rate and its surrogates in a square cylinder wake flow

N. Lefeuvre (1) , F. Thiesset (1) , L. Djenidi (2) , R. A. A Antonia (2)

1 UoN - University of Newcastle [Callaghan, Australia]
2 Newcastle University [Newcastle]

A numerical simulation based on the lattice Boltzmann method is carried out in the wake of a square cylinder with the view to investigating possible surrogates for the instantaneous turbulent kinetic energy dissipation rate, ε, as well as its mean value, ε Various surrogate approximations of ε, based on local isotropy (εiso), local axisymmetry along the streamwise direction x (εa, x) and the transverse direction y (εa, y), local homogeneity (εhom), and homogeneity in the transverse plane, (ε4x), are assessed. All the approximations are in agreement with ε when the distance downstream of the obstacle is larger than about 40 diameters. Closer to the obstacle, the agreement remains reasonable only for εa,x, εhom and ε4x. The probability density functions (PDF) and joint PDFs of ε and its surrogates show that ε4x correlates best with ε while εiso and εhom present the smallest correlation. The results indicate that ε4x is a very good surrogate for ε and can be used for correctly determining the behaviour of ε.

Mots clés: Numerical simulation; Wake

Domaines: Milieux fluides et réactifs

N. Lefeuvre, F. Thiesset, L. Djenidi, R. A. A Antonia. Statistics of the turbulent kinetic energy dissipation rate and its surrogates in a square cylinder wake flow. Physics of Fluids, 2014, 26 (9), pp.095104. ⟨10.1063/1.4895637⟩. ⟨hal-01660268⟩