Poiseuille flow calculator
Explore poiseuille flow with the method’s inputs, acquisition guidance and source references. Open the calculator to enter measurements or try an illustrative worked example.
Method
Q = πr⁴ΔP/(8ηL); R = 8ηL/(πr⁴)
Use the measurement units shown below. Some fields apply only to a selected method or condition; follow the interactive tool’s method choices. The interactive tool keeps missing measurements incomplete and provides its method-specific results and reference context.
Measurements and acquisition
Tube radius · r mm
Enter the measured value in the displayed unit
- Confirm the variable matches the selected formula.
- Use the unit displayed beside the field.
- Keep measurements from the same representative hemodynamic state.
Tube length · L cm
Enter the measured value in the displayed unit
- Confirm the variable matches the selected formula.
- Use the unit displayed beside the field.
- Keep measurements from the same representative hemodynamic state.
Dynamic viscosity · η mPa·s
Enter the measured value in the displayed unit
- Confirm the variable matches the selected formula.
- Use the unit displayed beside the field.
- Keep measurements from the same representative hemodynamic state.
Pressure drop · ΔP mmHg
Enter the measured value in the displayed unit
- Confirm the variable matches the selected formula.
- Use the unit displayed beside the field.
- Keep measurements from the same representative hemodynamic state.
Sources and method context
OpenStax · Rice University · 2016 · Poiseuille flow in a circular tube · University Physics Vol. 1 §14.7 · viscosity and laminar flow
- Flow and resistance · OpenStax University Physics Vol. 1 §14.7
Q = πr⁴ΔP/(8ηL) for ideal laminar flow in a uniform tube. R = 8ηL/(πr⁴); holding flow fixed requires ΔP = QR.
- Circular velocity profile · Deville, An Introduction to the Mechanics of Incompressible Fluids (2022), §3.2.2, doi:10.1007/978-3-031-04683-4_3
The fully developed circular-pipe profile is parabolic, zero at the wall, with centreline speed twice the area-averaged speed.
- Explicit input units · NIST SP 811 Appendix B.9 · pressure and dynamic viscosity
One conventional mmHg is 133.3224 Pa. One mPa·s is 0.001 Pa·s, numerically equal to one centipoise.
Catalogue review status: Source mapped · clinical sign-off pending
These pages describe the educational tool. Interpret measurements with the complete clinical context and the method’s acquisition limitations.