{ "id": "1912.10121", "version": "v1", "published": "2019-12-20T22:13:50.000Z", "updated": "2019-12-20T22:13:50.000Z", "title": "On the global wellposedness for free boundary problem for the Navier-Stokes systems with surface tension", "authors": [ "Hirokazu Saito", "Yoshihiro Shibata" ], "categories": [ "math.AP" ], "abstract": "The aim of this paper is to show the global existence of solutions to the Navier-Stokes equations, including surface tension and gravity, with a free surface on an unbounded domain such as bottomless ocean. In addition, it is proved that the solution decays polynomially as time $t$ tends to infinity. To show these results, we first use the Hanzawa transformation in order to reduce the problem on a time-dependent domain $\\Omega_t$, $t>0$, to a problem on the lower half-space $\\mathbf{R}_-^3=\\{(x',x_3) \\mid x'=(x_1,x_2)\\in\\mathbf{R}^2,x_3<0\\}$. We then establish some time-weighted estimate of solutions, in an $L_p$-in-time and $L_q$-in-space setting, for the linearized problem around the trivial steady state with the help of $L_r\\text{-}L_s$ decay estimates of semigroup associated with the linearized problem. Next, the time-weighted estimate, combined with the contraction mapping principle, shows that the transformed problem on $\\mathbf{R}_-^3$ admits in the $L_p\\text{-}L_q$ setting a unique solution global in time and that the solution decays polynomially as time $t$ tends to infinity under the assumption that the exponents $p$, $q$ satisfy the conditions: $2