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An unfitted Eulerian finite element method for the time-dependent Stokes problem on moving domains. (English) Zbl 1502.65147

Summary: We analyse a Eulerian finite element method, combining a Eulerian time-stepping scheme applied to the time-dependent Stokes equations with the CutFEM approach using inf-sup stable Taylor-Hood elements for the spatial discretization. This is based on the method introduced by C. Lehrenfeld and M. Olshanskii [ESAIM, Math. Model. Numer. Anal. 53, No. 2, 585–614 (2019; Zbl 1422.65223)] in the context of a scalar convection-diffusion problems on moving domains, and extended to the nonstationary Stokes problem on moving domains by E. Burman et al. [Numer. Math. 150, No. 2, 423–478 (2022; Zbl 07493698)] using stabilized equal-order elements. The analysis includes the geometrical error made by integrating over approximated level set domains in the discrete CutFEM setting. The method is implemented and the theoretical results are illustrated using numerical examples.

MSC:

65M60 Finite element, Rayleigh-Ritz and Galerkin methods for initial value and initial-boundary value problems involving PDEs
65M06 Finite difference methods for initial value and initial-boundary value problems involving PDEs
65N30 Finite element, Rayleigh-Ritz and Galerkin methods for boundary value problems involving PDEs
76D07 Stokes and related (Oseen, etc.) flows
35Q35 PDEs in connection with fluid mechanics
35R37 Moving boundary problems for PDEs