Experimental Study of Fluid Flow through Model Fractures

Abstract

The pressure drop through model fractures has been studied experimentally. The model fractures are made of two parallel acrylic plates whose dimensions are 2m (length)×0.44m (width), and the created aperture has the dimension of 4mm, which is common to all model fractures. In the midportion of the opening space (lm in length) rectangular obstacles whose cross sections have the dimension of 10mm in length and the three different heights of 1, 2 and 3mm are glued to both upper and lower plates with the interval of 30mm. The obstacles are oriented normal to the flow direction. The water is pumped up from the reservoir and led to the one end of the model fracture. The pressure drops along the flow direction are monitored. Using the streakline visualization technique the nature of water flow in the model fracture, for example laminar or turbulent, is also determined. An equation to predict the friction coefficient for a given Reynolds number, a number of the obstacles and their heights has been proposed; the experimental results are compared well with the theoretical prediction.