Fluid-structure interaction simulation based on immersed boundary-lattice Boltzmann flux solver and absolute nodal coordinate formula

Large deformation fluid-structure interaction (FSI) is a typical nonlinear problem in aero elastics. Engineering applications can be found in aviation, marine engineering, and bio-fluid mechanics. A three-dimensional (3D) parallel FSI solver based on an immersed boundary-lattice Boltzmann flux solver (IB-LBFS) and absolute nodal coordinate formula (ANCF) is established. The computational efficiency of the parallel IB-LBFS with moving boundaries is improved by several acceleration techniques, including Euler-Lagrangian interpolation matrix parallel assembling and sparse matrix solving methods. Structure dynamics simulation discretized in high-order ANCF elements distinctly reduces the number of finite elements compared with the standard finite element method. A multiple body dynamics (MBD) solver including a rigid body, ANCF cable elements, and ANCF plate elements is developed. The IB-LBFS, MBD solver, and coupled FSI solver are tested by the corresponding validation examples. A framework of solving 3D FSI problems of complex multiple flexible structures with large deformation in incompressible flow is presented. An implicit boundary condition enforced method is applied to achieve a strong coupling approach. For application demonstration, the inflation process of several types of parachute systems is simulated in which different Young's moduli of the parachute canopy are considered. The interaction between dynamic deformation and an unsteady vortex is obtained and discussed.