DOI: 10.1615/TSFP9
DNS OF A FULLY DEVELOPED TURBULENT POROUS CHANNEL FLOW BY THE LATTICE BOLTZMANN METHOD
Краткое описание
To understand the turbulent flow physics over permeable porous surfaces, a direct numerical simulation (DNS) of a turbulent channel flow over a porous layer is performed by the D3Q27 multiple-relaxation time lattice Boltzmann method. The bulk mean Reynolds number is 3000 and the presently considered porous layer, whose porosity is 0.71, consists of staggered cube arrays. Using the DNS results, the phenomenological discussions through the two-point autocorrelation, one-dimensional energy spectrum and proper orthogonal decomposition (POD) analyses are carried out. The reason why the streaky structure over the porous layer becomes shorter, wider and obscurer than that near the solid wall are discussed. It is found that the low wavenumber turbulence is enhanced over the porous layer. This low wavenumber large-scale motions are considered to stem from the Kelvin-Helmholtz instability due to the weakened wall-blocking effect and the strong shear over the porous layer.