In: Civil Engineering
he pressure of water at a depth of 10 km in the ocean is measured to be 100 MN/m2. The specific weight of the sea water at the surface is 10.2 kN/m3 while the average bulk modulus is 2.4 x 106 kN/m2. Calculate a) Change in specific volume (dV) between the volume at surface and at the 10 km depth. [4] b) The specific volume [3] c) Specific weight of the sea water at 10 km
solution: (a) change in specific volume can be well calculated using formula of bulk modulus which is given by:
B = P
V /
V
Where B is bulk modulus, v is specific volume, P is pressure and
show the change
in particulars.
pressure at the surface of sea water is always atmospheric pressure which is = 101.325 KN/m2
therefor P = 100000 -
101.325 = 99898.6 KN/m2
V = volume/ mass = density-1 = 1/10.2 = 0.098 m3
now, V =
P
V / B = 99898.6
0.98 / 2.4
106 =
0.0408 m3
(b) specific volume = volume / mass = density-1 = 0.098 m3
(c) specific weight at 10 km depth is given by pressure formula, which is:
P = gh where
g =
specific weight
g = P/h = 100000 /
10000 = 10 KN/m2