Wetted Perimeter of a Channel

The wetted perimeter of a channel refers to the length of the boundary between the channel and the water surface. It is the sum of the lengths of the bottom and the two sides of the channel that are in contact with the water.

Given Data:
Hydraulic radius (R) = 4.5 m
Cross-sectional area (A) = 18.5 sq.m

Calculating the Wetted Perimeter:

To calculate the wetted perimeter of the channel, we can use the formula:

Wetted Perimeter = (Cross-sectional area) / (Hydraulic radius)

Wetted Perimeter = A / R

Substituting the given values into the formula:

Wetted Perimeter = 18.5 sq.m / 4.5 m
Wetted Perimeter ≈ 4.11 m

Therefore, the wetted perimeter of the channel is approximately 4.11 meters.

Explanation:
Let's understand the formula used to calculate the wetted perimeter of a channel.

The hydraulic radius (R) is defined as the ratio of the cross-sectional area (A) of flow to the wetted perimeter (P). It represents the average distance from the flow area to the channel boundary.

R = A / P

Rearranging the equation, we can find the wetted perimeter:

P = A / R

In this case, we are given the values of the hydraulic radius and the cross-sectional area, and we need to calculate the wetted perimeter.

By substituting the given values into the formula, we can find the wetted perimeter of the channel.

It is important to note that the wetted perimeter is a significant parameter in hydraulic calculations, as it affects the flow resistance and the velocity of the water in the channel. It is used in various hydraulic design calculations, such as determining the flow rate, velocity, and friction losses in open channels.

In conclusion, the wetted perimeter of the channel is approximately 4.11 meters, given the hydraulic radius and the cross-sectional area.