A tank with 2000 L of water is placed 20 m above sea level with a pipe connected to it. The connection is a sharp reduction (L_e/D = 25). The tube has a length of 16 m and a diameter of 0.1 m.

1.- Assuming a frictionless system, what is the velocity at the end of the pipe?

2.- Now, the friction is not neglected but we assume that the velocity is the same as in 1. What is the friction loss and how long does it take to empty the tank?

In order to simplify the problem, assume:

The velocity in section 1 is negligible compared to section 2.

The velocity in section 2 is constant.

Both sections 1 and 2 are at atmospheric pressure.

Additional data: