2026/08/01 by Jinkai Ni, Luqi Wang, Zhipeng Zhang
Mathematics · #math.AP #msc:35Q30 #msc:35B40 #msc:76N15
35 pages. All comments are welcome
arxiv created 2026/08/01 · arxiv updated 2026/08/04
We study the Cauchy problem for the three-dimensional barotropic compressible Navier--Stokes equations with a time-independent potential force near a spatially nonconstant stationary state. The potential is controlled in unweighted homogeneous Besov spaces; in particular, no polynomial spatial-weight condition involving (1+|x|)j∇jϕ is imposed. For initial data relative to the stationary state that are sufficiently small in H\frac12-δ∩ H3, we establish the existence and uniqueness of a global strong solution in H3, while allowing the initial L2 norm to be arbitrarily large. If the initial data are bounded in Bs2,∞ for s∈[-\frac32,-1), then the solution and its first spatial derivative decay at the optimal rates (1+t)-(k-s)/(2) with k=0 and 1, respectively. The analysis relies on refined homogeneous energy estimates and a frequency-localized description for the dissipative and asymptotic structures of the system.