Created By : Vaibhavi Kumari

Reviewed By : Rajashekhar Valipishetty

Last Updated : May 15, 2023


The area, hydraulic radius, and wetted perimeter of an item are quickly calculated with this online hydraulic radius calculator. Select the object shape, enter the radius in the input section, and then push the calculate button to get the result fast.

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Height(h):
Width(B):

What is Hydraulic Radius?

The hydraulic radius is the proportion of the flow's cross-sectional area to the wetted perimeter. Rectangle, pipe with full, pipe with a partially filled, trapezoid, and triangle are the various channels.

The area of a channel that is in contact with the fluid it transports is referred to as the wetted perimeter. Hydraulic radius and wetted perimeter are significant flow parameters to consider while building a sewerage system.

The formulas for calculating the wetted perimeter and hydraulic radius of various shapes are listed below.

  • The wetted perimeter of full pipe is P = 2πr
  • Hydraulic Radius of full pipe R = A/P = πr²/2πr = r/2
  • Pipe(less than half) Wetted Perimeter P = r * θ and θ = 2 * arccos [(r - h) / r]
  • Area A = r² * (θ - sin(θ)) / 2
  • Hydraulic Radius R = A/P = [r² * (θ - sin(θ)) / 2]/[r * θ and θ = 2 * arccos [(r - h) / r]] = [r² * (θ - sin(θ)) / 2] / (r * θ)

Area, Wetted Perimeter, Hydraulic Radius of Different Channels

Triangular Channel

  • Area A = B * y / 2 = y²z
  • Wetted Perimeter P = 2 * y * √(1 + z²)
  • Hydraulic Radius R = A/P = yz / [2 * √(1 + z²)]

Rectangular Channel

  • Area A = b * y
  • Wetted Perimeter P = b + y + y = b + 2y
  • Hydraulic Radius R = A/P = (by)/(b + 2y)

Trapezoid Channel

  • Area A = y * (B + b)/2, B = b + 2zy
  • Wetted Perimeter P = b + 2 * y * √(1 + z²)
  • Hydraulic Radius R = A/P = (by + y²z)/[b + 2 * y * √(1 + z²)]

How to Compute Hydraulic Radius & Wetted Perimeter?

The steps for determining the wetted perimeter and hydraulic radius for five distinct shapes are outlined below. Examine the specifics and conform to them.

  • Step 1: Take note of the object's shape and the information provided.
  • Step 2: Get the wetted perimeter, area, and hydraulic radius formulas.
  • Step 3: To acquire the result, substitute the values in the equations and complete the computations.

For more concepts check out physicscalculatorpro.com to get quick answers by using this free tool.

FAQs on Hydraulic Radius Calculator

1. What does hydraulic radius mean?

The hydraulic radius is a measurement of the efficiency of a channel's flow. It's one of the most important characteristics that determine how much fluid a channel can discharge and how well it can carry sediments.


2. How do you distinguish between the hydraulic radius and hydraulic depth?

The ratio of cross-sectional area to the wetted perimeter is known as hydraulic radius. Hydraulic depth is defined as the depth that equals the irregular section area when multiplied by the topwater surface width. The hydraulic mean depth and radius formulas are A/T and A/P, respectively.


3. What is the trapezoidal's hydraulic radius?

A trapezoid's hydraulic radius is R = [h(b+zh)]/[(b + 2h√(1 + z2)]. Where b is the fluid's bottom width, h is its depth, and z is the channel slope's width.


4. What is the flow's hydraulic radius?

The ratio of the cross-sectional area of fluid flow, A, to the length of the wetted perimeter, P, is described as hydraulic radius, R, a measure of channel flow efficiency. The hydraulic radius is one of the most important parameters that determine how much fluid a channel can discharge and how well it can move sediments.


5. What is the definition of hydraulic radius?

The ratio of the cross-sectional area of a fluid-flowing channel or pipe to the wetted perimeter of the conduit.


6. What is the hydraulic mean depth R?

The hydraulic mean depth, also known as the hydraulic radius, is the proportion of flow area to the wetted perimeter.