Variational multiscale computational fluid–structure interaction analysis of Wells turbine passive-adaptive blades

We present an arbitrary Lagrangian–Eulerian variational multiscale (ALE-VMS) computational fluid–structure interaction (FSI) analysis of Wells turbine passive-adaptive blades. We use finite element discretization. The ALE-VMS, as the core method, is complemented with the linear-elasticity mesh moving with mesh-Jacobian-based stiffening and block-iterative FSI coupling. We explore new designs for adaptive (morphing) blades that adapt to changes in flow direction, focusing on small-size reversible turbines. We first conduct a 2D study with a blade made of low-stiffness material. The goal is to achieve a stable passive change in airfoil curvature in response to the aerodynamic forces. With this 2D cascade study, we verify the feasibility of the concept and explore the use of different materials layouts. Then, we conduct a 3D study with time-dependent flow rate, simulating the turbine’s operation in an oscillating water column facility for sea wave energy conversion. The results show that advanced computational FSI analysis provides useful insight into the functioning of these devices.