The tube in Problem 4-20 is connected to a source of flowing water, and water is passed through the tube at a rate of 100 cm3 s-1. If the pollutant concentration in the water is constant at 2 mg L-1, what is
(a) The mass flux density of the pollutant through the tube due to advection?
(b) The total mass flux through the tube due to advection?
Problem 4-20
The concentration of a pollutant along a quiescent water-containing tube is shown in Figure 4-23. The diffusion coefficient for this pollutant in water is equal to 10-5 cm2 s-1.
(a) What is the initial pollutant flux density in the x-direction at the following locations: x - 0.5, 1.5, 2.5, 3.5, and 4.5?
(b) If the diameter of the tube is 3 cm, what is the Initial flux of pollutant mass in the x-direction at the same locations?
(c) As time passes, this diffusive flux will change the shape of the concen-tration profile. Draw a sketch of concentration in the tube versus x-axis location showing what the shape at a later time might look like.
