Urinary flow through urethras with a rough lumen.
Patricia J YangTony G ChenSarah B BracherAaron HuiDavid L HuPublished in: Neurourology and urodynamics (2023)
Based on the behavior of our mimics, we conclude that the lumen roughness in mammals reduces flow speed by up to 25% compared to smooth urethras. Urine flows fastest when the urethra length exceeds 25 times its diameter. Longer urethras do not drain faster due to viscous effects counteracting the additional gravitational head. However, flows with our urethra mimics are still 6 times faster than those observed in nature, suggesting that further work is needed to understand flow resistance in the urethra.