Navier-Stokes flow past a rigid body: attainability of steady solutions as limits of unsteady weak solutions, starting and landing cases
arXiv:1704.00452 · doi:10.1007/s00021-017-0344-3
Abstract
Consider the Navier-Stokes flow in 3-dimensional exterior domains, where a rigid body is translating with prescribed translational velocity with constant vector . Finn raised the question whether his steady slutions are attainable as limits for of unsteady solutions starting from motionless state when after some finite time and (starting problem). This was affirmatively solved by Galdi, Heywood and Shibata for small . We study some generalized situation in which unsteady solutions start from large motions being in . We then conclude that the steady solutions for small are still attainable as limits of evolution of those fluid motions which are found as a sort of weak solutions. The opposite situation, in which after some finite time and (landing problem), is also discussed. In this latter case, the rest state is attainable no matter how large is.