Viscous damping, solid piston in a cylindrical bore

Damping constant of a solid (bore-less) piston sliding in a viscous-fluid-filled cylinder, given both as pressure-driven (Poiseuille) squeeze flow and as pure Couette drag flow across the radial gap.

✓ validated against legacyoriginal: /calculators/damping_1.htm

Piston radius, R₀10⁻³ mPiston length, L10⁻³ mRadial gap size, h₀10⁻³ mFluid viscosity, ηPa·s

Damping constant, pressure flow, C30.16 10³ Ns/m

Damping constant, Couette flow, C0.25 Ns/m

Method & references

Viscous damping of a solid piston in a cylindrical bore — pressure-driven (Poiseuille) squeeze flow vs. Couette shear flow across the radial gap.

The computation is a literal port of the original client-side JavaScript from /calculators/damping_1.htm. Results are verified equal to the original by an automated golden-master test. No formula has been re-derived or “improved”.

Viscous damping, solid piston in a cylindrical bore — Engineering ABC