Turbulent flow in porous media

Turbulent-laminar flow transitions in porous media: solute transport in river and groundwater

Natural rivers and unpaved water channels involve turbulent surface flows over a permeable bed. Surface water enters the soil layer via infiltration and eventually becomes part of the groundwater flow. Apart from soil properties, the infiltration rate is highly dependent on the structures of the turbulent boundary layer adjacent to the porous bed. For sand beds with pore sizes of about 1mm, recent numerical studies found that the flow inside the pore matrix can become transitional and departs from the laminar Darcy flow regime; the Darcy coefficient is a function of the pore flow’s Reynolds number. Dispersion characteristics also change due to the change in flow regime. The project goal is to understand the different flow regimes and physics as a function of pore size and pore matrix using laboratory experiments. First part of the experimental program will focus on the effects of zero-mean flow, homogeneous isotropic turbulence (HIT) created above the porous bed. Second part will study the effects of a turbulent channel flow. Refractive-index matching (RIM) techniques will be used to measure flows inside the pores and a random-jet stirred tank will be built to create HIT.