Abstract
In order to understand the effects of the wall permeability on turbulence near permeable walls, flow field measurements are carried out for turbulent flows in a channel with permeable bottom walls by a two-component particle velocimetry (PIV) system. The porous media used axe three kinds of foamed ceramics which have almost the same porosity (〜 0.8) but different permeability.The turbulent flow fields in the x-z planes are discussed using instantaneous and statistical measurement data. At a small permeability Re (Re_K), high speed and low speed regions, which form a similar structure to that of solid-wall turbulence, are observed. In case of a large Re a:, some large scale striped patterns are observed, although it is a different structure of turbulence from that of solid walls.
