Lei de Poiseuille (vazão)

The Poiseuille Law calculator determines the volumetric flow rate Q of a viscous fluid in a cylindrical tube. The formula Q = πΔPr⁴/(8μL) relates flow rate to pressure difference ΔP, tube radius r, dynamic viscosity μ, and length L. This law describes laminar, incompressible, steady flow. It is fundamental for understanding how flow resistance depends strongly on radius (fourth power), meaning small diameter changes cause large flow variations.

To use the calculator, enter values for ΔP (in pascals), r (in meters), μ (in pascal-seconds), and L (in meters). The result is flow rate in m³/s. The calculation is straightforward from the formula. Ensure consistent units and that the flow is laminar (low Reynolds number). Otherwise, the law does not apply.

When to use? This calculator is useful in hydraulic engineering, irrigation systems, oil or gas circuits, and medical applications to assess blood flow in vessels. For example, to size pipes or analyze the effect of arterial narrowing. It is also applied in labs for viscous fluid studies.

Cautions: Poiseuille's Law assumes Newtonian fluid, laminar flow, straight and uniform tube, no turbulence. In real situations, check the Reynolds number (Re < 2000). Also, viscosity may vary with temperature. Accuracy depends on precise input parameters.