https://hal-polytechnique.archives-ouvertes.fr/hal-01025948Ueda, YoshiakiYoshiakiUedaKida, TeruhidoTeruhidoKidaNakanishi, MasatoMasatoNakanishiSellier, AntoineAntoineSellierLadHyX - Laboratoire d'hydrodynamique - X - Ă‰cole polytechnique - CNRS - Centre National de la Recherche ScientifiqueLow-Reynolds-Number Flow around an Impulsively Started Rotating and Translating Circular CylinderHAL CCSD2001[PHYS.MECA.MEFL] Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph][SPI.MECA.MEFL] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph]Roura, Denis2014-07-18 19:27:012023-03-24 14:52:592014-07-18 19:27:01enJournal articles10.1299/kikaib.67.16261This paper describes the two-dimensional unsteady low-Reynolds-number flow past an impulslvely started rotating and translating circular cylinder. Invoking the vorticity equation, we first derive a system of two coupled integral equations that govern the stream function and a modified vorticity function. This system, singular in the low-Reynolds-number, is then asymptotically solved by using a singular perturbation method and introducing five regions in the space-time domain. The first-order solutions are found to linearly depend on the translating and rotating motions within each region. Because of its importance for applications, a special attention is paid to the lift coefficient CL which results here from intricate interactions between rotation and translation. The obtained initial asymptotic behavior of CL actually exhibits a t-1/2 singularity and thereby differs from the prediction of Badr & Dennis(1) at moderate Reynolds numbers.