Transition to unsteady flow and intensity of velocity fluctuations in a porous medium

Abstract Direct measurements of local velocity and the intensity of velocity fluctuations in a pore of a number three rhombohedral array of spheres indicate a region of increasing intensity beginning at Reynolds number of about 80 and reaching a maximum intensity of approximately 0.6 at a Reynolds number of about 200. At higher Reynolds numbers the intensity falls to a constant value between 0.4 and 0.5.