Lundi 18 novembre 2024 à 11h, salle de séminaires IRPHE
Abstract : The ‘Rolling Paradox’ states that, according to lubrication theory, a smooth sphere cannot roll on a smooth surface due to infinite fluid resistance at the contact point. A number of possible mechanisms have been proposed to resolve this paradox, including cavitation.
In this seminar, we revisit whether surface roughness could be a preferable mechanism. Via combined experiments and computations, it is found that surface roughness could provide both a contact for non-slip as well as an effective gap to remove the singularity in resistance, thus resolving the ‘Rolling Paradox’. Intriguingly, a moderately rough sphere exhibits lower drag and higher rolling velocities than either a well-polished sphere or a substantially rough sphere.
Kerry Hourigan - Dpt. of Mechanical and Aerospace Engineering / Monash University Melbourne