Radius sensitivity of Poiseuille-flow uncertainty
= Radius sensitivity of Poiseuille-flow uncertainty
For $Q\propto a^4\Delta P/(\eta L)$ and independent small errors, $\sigma_Q^2/Q^2=16\sigma_a^2/a^2+\sigma_{\Delta P}^2/\Delta P^2+\sigma_\eta^2/\eta^2+\sigma_L^2/L^2$. Independent pressure errors add in quadrature before dividing by the pressure difference. Bounded worst-case errors instead add absolute <derivative> contributions.