On the well-posedness of Banach spaces-based mixed formulations for the nearly incompressible Navier-Lamé and Stokes equations

• Published in: Computers & mathematics with applications (1987) Vol. 102; pp. 87 - 94
• Main Authors: Gatica, Gabriel N., Inzunza, Cristian
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 15.11.2021; Elsevier BV
• Subjects: Banach spaces; Continuum mechanics; Elasticity; Formulations; Inf-sup conditions; Lebesgue spaces; Linear elasticity; Mathematical analysis; Mixed formulation; Navier-Stokes equations; Operators (mathematics); Sobolev space; Sobolev spaces; Stokes; Tensors; Well posed problems; Lebesgue spaces; Stokes; Inf-sup conditions; Sobolev spaces; Linear elasticity; Mixed formulation
• ISSN: 0898-1221; 1873-7668
• DOI: 10.1016/j.camwa.2021.10.004

In this paper we introduce and analyze, up to our knowledge for the first time, Banach spaces-based mixed variational formulations for nearly incompressible linear elasticity and Stokes models. Our interest in this subject is motivated by the respective need that arises from the solvability studies of nonlinear coupled problems in continuum mechanics that involve these equations. We consider pseudostress-based approaches in both cases and apply a suitable integration by parts formula for ad-hoc Sobolev spaces to derive the corresponding continuous schemes. We utilize known and new preliminary results, along with the Babuška-Brezzi theory in Banach spaces, to establish the well-posedness of the formulations for a particular range of the indexes of the Lebesgue spaces involved. Among the aforementioned new results from us, we highlight the construction of a particular operator mapping a tensor Lebesgue space into itself, and the generalization of a classical estimate in L2 for deviatoric tensors, which plays a key role in the Hilbertian analysis of linear elasticity, to arbitrary Lebesgue spaces. No discrete analysis is performed in this work.