# Velocity of Flow

## Problem 06 - Bernoulli's Energy Theorem

**Problem 6**

As shown in Figure 4-03, the smaller pipe is cut off a short distance past the reducer so that the jet springs free into the air. Compute the pressure at 1 if Q = 5 cfs of water. D_{1} = 12 inches and D_{2} = 4 inches. Assume that the jet has the diameter D_{2}, that the pressure in the jet is atmospheric and that the loss of head from point 1 to point 2 is 5 ft of water.

## 02 Graph of flow velocity in tapering pipe

**Problem**

The diameter of a 6-m length pipe decreases uniformly from 450 mm to 150 mm. With a flow of 0.15 m^{3}/sec of oil, compute the mean velocity at cross section 1 m apart. Plot the velocity as ordinate against length as abscissa.

Graph of velocity of flow versus length of pipe (plotted in MS Excel)

## 01 How to calculate the discharge and the velocity of flow

**Problem 1**

Compute the discharge of water through 75 mm pipe if the mean velocity is 2.5 m/sec.

**Problem 2**

The discharge of air through a 600-mm pipe is 4 m^{3}/sec. Compute the mean velocity in m/sec.

**Problem 3**

A pipe line consists of successive lengths of 380-mm, 300-mm, and 250-mm pipe. With a continuous flow through the line of 250 Lit/sec of water, compute the mean velocity in each size of pipe.