Question

It is desired to understand the settling of sediments in a river. Assuming the specific gravity equals 2.2, compute the settling velocity of solid spherical particles having diameters of: 15 microns, 100 microns, 250 microns, 400 microns, 1.0 mm, 3.0 mm, 5.0 mm, 10 mm, and 40 mm. Assume standard conditions. Plot the velocity as function of the diameter. Use both linear scale and logarithmic scale.

Answer 1

3 Cd P) Diameter Vs o 0 3 m/s I mm 18 3 s 5 mm o m78 o mm 1. Ib m/s

V vs D 1.4 1.2 0.8 0.6 0.4 0.2 0 0.00E+00 5.00E-03 1.00E-02 1.50E-02 2.00E-02 2.50E-02 3.00E-02 3.50E-02 4.00E-02 4.50E-02 D (m)

V vs D 1.4- 1.2- 0.4 1.00E-05 1.00E-04 1.00E-03 1.00E-02 1.00E-01 1.00E+00 D (m)