14/06/2018 - Bruno Voisin
Rotation alters fundamentally the wake of a moving body, or the flow past a fixed obstacle : inertial waves are generated and vortex shedding is hindered. We present a joint theoretical and experimental study of the wake of a horizontal cylinder in uniform horizontal translation perpendicular to its axis in a fluid rotating about the vertical. The stability and structure of the wake are considered as the Reynolds and Rossby numbers vary. The theory is linear while the experiments involve PIV measurements. A remarkable feature of the theory is that, as a consequence of two-dimensionality in a rotating fluid, the moving cylinder can be considered slender even though it is not.
This work is the outcome of a collaboration with Pierre-Philippe Cortet, Nathanaë l Machicoane, Frédéric Moisy and Vincent Labarre, of the FAST laboratory at Université Paris-Saclay where the experiments were performed on the GyroFlow rotating tank.
An account has been published as "Wake of inertial waves of a horizontal cylinder in horizontal translation", Physical Review Fluids 3, 034801 (2018), https://doi.org/10.1103/PhysRevFluids.3.034801