ABSTRACT
Formulation of problem: Determine the hydraulic conductivity and permeability of a coarse
sand sample that was tested in the laboratory with a constant head permeameter. The results
of the test are given in Table 9.1. The fluid used for testing was deaired water with a
temperature of 238C. The apparatus used for testing was Darcy’s constant head permeameter, explained in Section 1.4.2 (Figure 1.33). The inside diameter of the sample tubing was 1 7=8 in. (4.8 cm) and the length of the sand sample was 6 in. (15.2 cm). The experiment consisted of
10 individual tests each with a different position of the constant head (the head difference
between the constant head and the head of the permeameter outlet is given in Table 9.1). The
flow rate for each test was determined by measuring the volume of water collected at the outlet
and the corresponding time. After determining the hydraulic conductivity for water as the test
fluid, calculate what the hydraulic conductivity of the sample would be if, instead of water,
the test fluid was gasoline at 188C (kinematic viscosity of gasoline at 188C is 6.5 107 m2=s).
The permeameter (shown in Figure 1.33) is based on Darcy’s apparatus named after Henry
Darcy, a French civil engineer who formulated the equation of flow of water through
intergranular porous media. The rate of a fluid flow (Q) through a sand sample is directly
proportional to the cross-sectional area of the flow (A) and the loss of the hydraulic head
between two points of measurements (Dh), and it is inversely proportional to the length of the sample (l):
