Energy transfer in turbulence using Lattice Boltzmann Method based on large-eddy simulation
Résumé
Turbulent flows are characterized by the emergence of simultaneous downscale and upscale energy
transfer. The challenge is to control the velocity in two complex geometries. A spectral analysis and a
fluctuation velocity were performed on the numerical data obtained from Lattice Boltzmann method
(LBM) and large-eddy simulation (LES) of the turbulent flow. In this context, the background of LBM
is presented and the construction of Navier-Stokes equations from Boltzmann equation is discussed. The
LBM-LES model was developed for solving transition and implanted turbulence modeling. A Fourier
transform was chosen to study signals from LBM-LES model and to provide a local analysis of transient
turbulent events. The flow in a cavity, as well as the flow around a cylindrical obstacle, were studied
with a focus on the evolution of these flows at a high Reynolds number. The simulation results show
that the LBM-LES model can produce results in good agreement with other numerical methods and
experimental data. It should be noted that this model is easy to apply to complex geometries. The
investigated geometries are to be considered a first step that provides, validates, and reliable simulation
of the specific properties of the turbulent regime. The behavior of streamlining plots with increasing
Reynolds number is exhibited. In the present study, a new method is developed to measure the
fluctuating velocity in the turbulent boundary layer. The analyses data were taken from a different
position inside the flows, allowing investigation of the turbulent flow. The shear effect on Kolmogorov’s
−3 power-law scaling of the energy spectrum is discussed