Scale estimation for turbulent flows in porous media

The results of an experimental study to determine the smallest, dissipative scales of the turbulent flow in a randomly packed porous bed are presented and discussed. Particle Image Velocimetry was used to obtain time dependent two-dimensional velocity fields within the bed, which were then used to obtain turbulent statistical measures within the flow field. Results are presented for representative pores for a range of pore Reynolds numbers, Repore, from 839 to 3964, which include integral length and velocity scales and estimates of the Kolmogorov scales of length, velocity and time. The results show an asymptotic region at sufficiently high Repore, on the order of 2800, where scaling is normalized using the bed pore scales. It is also shown that the turbulent Reynolds number for this flow in the asymptotic limit is on the order of 0.07Repore, for the range of pores studied.