An immersed interface method for discrete surfaces

• Published in: Journal of computational physics Vol. 400; p. 108854
• Main Authors: Kolahdouz, Ebrahim M., Bhalla, Amneet Pal Singh, Craven, Brent A., Griffith, Boyce E.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.01.2020; Elsevier Science Ltd
• Subjects: Accuracy; Complex geometries; Computational physics; Computer simulation; Convergence; Deoxygenation; Finite element; Finite element method; Fluid-structure interaction; Hemodynamics; Immersed boundary method; Immersed interface method; Interfaces; Jump conditions; Numerical methods; Representations; System effectiveness; Velocity distribution; Velocity gradient; Wall shear stresses; Immersed boundary method; Immersed interface method; Jump conditions; Complex geometries; Fluid-structure interaction; Finite element; complex geometries; jump conditions; immersed boundary method; fluid-structure interaction; finite element; immersed interface method
• ISSN: 0021-9991; 1090-2716
• DOI: 10.1016/j.jcp.2019.07.052

Fluid-structure systems occur in a range of scientific and engineering applications. The immersed boundary (IB) method is a widely recognized and effective modeling paradigm for simulating fluid-structure interaction (FSI) in such systems, but a difficulty of the IB formulation of these problems is that the pressure and viscous stress are generally discontinuous at fluid-structure interfaces. The conventional IB method regularizes these discontinuities, which typically yields low-order accuracy at these interfaces. The immersed interface method (IIM) is an IB-like approach to FSI that sharply imposes stress jump conditions, enabling higher-order accuracy, but prior applications of the IIM have been largely restricted to numerical methods that rely on smooth representations of the interface geometry. This paper introduces an immersed interface formulation that uses only a C0 representation of the immersed interface, such as those provided by standard nodal Lagrangian finite element methods. Verification examples for models with prescribed interface motion demonstrate that the method sharply resolves stress discontinuities along immersed boundaries while avoiding the need for analytic information about the interface geometry. Our results also demonstrate that only the lowest-order jump conditions for the pressure and velocity gradient are required to realize global second-order accuracy. Specifically, we demonstrate second-order global convergence rates along with nearly second-order local convergence in the Eulerian velocity field, and between first- and second-order global convergence rates along with approximately first-order local convergence for the Eulerian pressure field. We also demonstrate approximately second-order local convergence in the interfacial displacement and velocity along with first-order local convergence in the fluid traction along the interface. As a demonstration of the method's ability to tackle more complex geometries, the present approach is also used to simulate flow in a patient-averaged anatomical model of the inferior vena cava, which is the large vein that carries deoxygenated blood from the lower and middle body back to the heart. Comparisons of the general hemodynamics and wall shear stress obtained by the present IIM and a body-fitted discretization approach show that the present method yields results that are in good agreement with those obtained by the body-fitted approach. •This paper introduces an immersed interface method for discrete surface representations.•Accurate jump conditions are evaluated along C0 interface representations using L2 projections.•Verification tests show second-order global and nearly second-order local convergence in the Eulerian velocity.•These tests show between first- and second-order global and nearly first-order local convergence for the Eulerian pressure.•Flow simulation using an anatomical inferior vena cava model demonstrates the methods ability to treat complex geometries.