Page 91 - Materials Chemistry, Second Edition

74 Practical Design Calculations for Groundwater and Soil Remediation

TABLE 3.2
Physical Properties of Water under One Atmosphere
Temperature Density Viscosity
3
(°C) (g/cm ) (cP)
0 0.999842 1.787
3.98 1.000000 1.567
5 0.999967 1.519
10 0.999703 1.307
15 0.999103 1.139
20 0.998207 1.002
25 0.997048 0.890
30 0.995650 0.798
40 0.992219 0.653
Note: 1 g/cm = 1,000 kg/m = 62.4 lb/ft ; 1 centipoise
3
3
3
(cP) = 0.01 poise = 0.01 g/cm∙s = 0.001 Pa∙s = 2.1 ×
10 lb∙s/ft . 2
−5
3
essentially the same, at approximately 1 g/cm ; the viscosity of water
decreases with increasing temperature. The viscosity of water at 20°C is 1
centipoise. (Note: This is the viscosity value of the fluid used in defining
the darcy unit.)

Example 3.4: Determine Hydraulic Conductivity from
a Given Intrinsic Permeability
The intrinsic permeability of a soil core sample is 1 darcy. What is the hydrau-
lic conductivity of this soil for water at 15°C? How about at 25°C?

Solution:
(a) At 15°C,
density of water (15°C) = 0.999703 g/cm (from Table 3.2)
3
viscosity of water (15°C) = 0.01139 poise = 0.01139 g/s∙cm (from
Table 3.2)
kgρ (9.87 10 cm )(0.999703 g/cm )(980 cm/s )× − 9 2 3 2
K = = = 8.49 10 cm/s× − 4
µ 0.01139 g/scm⋅
= (8.49 10 )(2.12 10 ) 18.0 gpd/ft× − 4 × 4 = 2 = 18.0 meinzer

(b) At 25°C,
3
density of water (25°C) = 0.997048 g/cm (from Table 3.2)
viscosity of water (25°C) = 0.00890 poise = 0.00890 g/s∙cm (from
Table 3.2)