Fluxo Poiseuille
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
About this calculator
The Poiseuille Flow Calculator is an online tool that calculates the flow rate of a fluid through a cylindrical tube, based on the Poiseuille equation. This equation relates the flow rate (Q) to the pressure drop (ΔP), tube radius (R), fluid dynamic viscosity (μ), and tube length (L). The formula is Q = πR⁴ΔP/(8μL), providing an accurate result for laminar flow of Newtonian fluids.
The Poiseuille equation is fundamental in fluid physics and is used to predict fluid behavior in tubes. It assumes laminar flow, where fluid layers move smoothly over each other without turbulence. This is common in many practical applications, such as blood flow in veins and arteries, oil flow in pipelines, and gas flow in ducts.
The Poiseuille Flow Calculator is useful in various situations, such as designing piping systems, calculating head losses, and sizing pumps and valves. It can also be used to estimate the viscosity of an unknown fluid by measuring the flow rate and pressure drop in a tube of known length and radius.
When using the calculator, it's essential to ensure consistent units of measurement with those in the Poiseuille equation. Additionally, it's crucial to remember that the equation assumes laminar flow and a Newtonian fluid, which may not be valid in all real-world situations.
Frequently asked questions
What is laminar flow?
Laminar flow is a type of fluid flow where fluid layers move smoothly over each other without turbulence.
What are the units of measurement for the Poiseuille equation?
Common units are: Q (m³/s), R (m), ΔP (Pa), μ (Pa·s), and L (m).
Is the Poiseuille equation valid for all fluids?
No, the Poiseuille equation assumes the fluid is Newtonian, meaning its viscosity is constant and independent of shear rate.
How can I use the calculator to estimate fluid viscosity?
By measuring the flow rate and pressure drop in a tube of known length and radius, and rearranging the Poiseuille equation to solve for viscosity.