On the Gravity-Driven Sliding Motion of a Planar Board on a Tilted Soft Porous Layer

In this paper, we report a novel experimental study to investigate the gravity-driven sliding motion of a planar board over a tilted soft porous layer. A laser displacement sensor was used to measure the motion of the board, while a high-speed camera was adopted to capture the detailed compression of the porous layer when the board glided over it. The pore pressure generation, as a result of the compression, was recorded by pressure sensors mounted on the bottom surface of the porous layer. One finds that, the pressure distribution agrees well with the theory developed by Wu and Sun (Med Sci Sports Exerc 43:1955-1963, 2011). Extensive parametric study was performed by varying the center of gravity of the planar board, the tilted angle and the porous material. Consistent agreement between the theoretical predictions and experimental results was obtained. It shows that, the effect of soft porous lubrication is enhanced when the center of gravity moves toward to the trailing edge of the planar board, or the tilted angle of the porous layer is increased, or a smoother fibrous surface is used. [GRAPHICS] .