Experimental investigation on macro-mesoscopic characteristics of seepage flow in transparent porous media.

• Capture the global and localized characteristics of seepage flow in porous media using visualization seepage technology. • Investigate the connection of macro and mesoscopic characteristics of seepage flow in porous media. • Reveal the reason why the global and localized seepage regions are different. Aiming to investigate the macro-mesoscopic characteristics of seepage flow in porous media, flume experiments have been conducted with the visualization technology. As comparisons, a series of numerical simulations were performed. The results show that the local flow regime of seepage in porous media can be different from the global flow regime. It is found that the seepage velocity in the middle region is lower than that near the wall of flume. This phenomenon is more obvious in the upper part of the porous media. It is proved by both numerical simulations and experiments that the small deviations in the size and position of internal pores are the reason for different flow characteristics between the local and global seepage fields. [ABSTRACT FROM AUTHOR]