Created By : Abhinandan Kumar

Reviewed By : Phani Ponnapalli

Last Updated : May 17, 2023

During a fluid flow, the Darcy Weisbach Calculator calculates the change in pressure or pressure drop caused by friction in a pipe. The Darcy Weisbach friction factor is calculated using the friction loss caused by roughness on the inner surface of a pipe. Pipes transfer fluids in a variety of applications, including water supply pumping. 

Pipe length (L)
Pipe diameter (D)
Flow velocity (V)
Density of fluid (ρ)
Darcy friction factor (f)
Choose the unit you want to calculate in

What is Darcy Weisbach's Equation?

An empirical equation is used to connect the friction in the pipe caused by surface roughness to the pressure loss. In addition to pipe dimensions like diameter and length, the equation takes into account fluid variables like density and flow velocity, as well as material properties like friction factors. The pressure loss ΔP for a pipe with diameter D and length L is stated mathematically as: ΔP = (f * L * V2 * ρ) / (2 * D),

  • Where, ρ = fluid density;
  • V = flow velocity; and
  • f = Darcy friction factor.

The Darcy Weisbach equation was named after Henry Darcy and Julius Weisbach, two engineers who worked together on the project. The pressure loss per unit length can also be expressed as follows: ΔP / L = (f * V2 * ρ) / (2 * D)

The Darcy friction factor, which is based on the material's surface and is extremely difficult to calculate, is a crucial part of the equation. A Moody diagram and the Colebrook-White equation are used in one of the solutions offered. The Colebrook equation can be used to calculate the Darcy Weisbach friction factor for a pipe with a surface roughness of k:

1/√f = -2 * log(k / (3.7 * D) + 2.51/(Re * √f)),

where Re is the fluid flow's Reynold's number. Lewis Moody proposed an approximate method known as Moody's approximation to solve the Colebrook-White equation:

f = 0.0055 (1 + (2 * 104 * k/D + 106/Re)1/3)

The friction factor is affected by surface roughness, k, and Reynold's number, which is calculated based on fluid flow parameters.

What factors Contribute to Pressure Drop?

Three types of factors influence the pressure drop in the Darcy Weisbach formula:

  • The length and diameter of a pipe are two important factors to consider.
  • Darcy Friction Factor is a material property.
  • The density and velocity of a fluid flow.

How do you find out how much pressure has dropped?

 <p>Using this Darcy Weisbach equation calculator, calculate the pressure drop as follows:</p>


            <li>Step 1: Calculate the diameter of the pipe, D.</li>

            <li>Step 2: Enter L, the pipe length.</li>

            <li>Step 3: Enter the velocity of the fluid flow, V.</li>

            <li>Step 4: Enter the density of the fluid, &rho;.</li>

            <li>Step 5: Enter the f value for the Darcy friction factor.</li>

            <li>Step 6: The pressure drop value will be returned by the Darcy Weisbach calculator.</li>


            <p>Become familiar with plenty of similar concepts of physics along with well designed calculator tools complementing the concept on <a href=""></a> a trusted reliable portal for all your needs.</p>

FAQs on Darcy Weisbach Calculator

1. What is the equation of Darcy Weisbach?

The Darcy Weisbach equation is used to calculate a fluid's pressure drop via a pipe.

ΔP = (f * L * V2 *ρ) / (2 * D) in mathematics, 

  • Where, P = pressure, 
  • f = friction factor, 
  • L = pipe length, 
  • V = flow velocity, 
  • D = pipe diameter, 
  • ρ = fluid density.

2. What is the Darcy Weisbach formula for frictional head loss?

The Formula for Darcy Weisbach's equation is as follows: hf = f l V^2/2gd.

3. Where does the Darcy-Weisbach equation come into play?

The Darcy–Weisbach equation is an empirical equation in fluid dynamics that connects the head loss, or pressure loss, generated by friction along a given length of the pipe to the average fluid flow velocity for an incompressible fluid. Henry Darcy and Julius Weisbach are the names of the equation.

4. Is the Darcy-Weisbach equation valid in turbulent flow?

For fully developed, steady-state, and incompressible flow, the Darcy-Weisbach equation is valid. The friction factor or coefficient is determined by the kind of flow (laminar, transient, or turbulent) and the roughness of the tube or duct (the Reynolds Number).

5. How to find out Pressure Drop?

Using the Darcy Weisbach formula, determine the pressure drop in a pipe:

  • Step 1: Multiply the friction factor by the length of the pipe and divide by the diameter of the pipe.
  • Step 2: Multiply the square of velocity to this product.
  • Step 3: Divide the result by two.