Fluid structure interaction analysis of a high aspect ratio aeroelastic wing considering geometric nonlinearity

High-aspect-ratio aeroelastic wings are essential for energy efficient greener aircraft with improved aerodynamic efficiency and performance. In this work, a computational procedure based on a coupled computational fluid dynamics (CFD)-computational structural dynamics (CSD) technique is established to study the static aeroelastic behavior of a high-aspect-ratio wing at various flow velocities. Since these wings are structurally very flexible and experience large deformations, the present fluid structure interaction (FSI) approach couples a Navier-Stokes (N-S) based CFD solver with a finite element method (FEM) based structural solver incorporating geometric nonlinearity. Here, the N-S solver is based on the finite volume method (FVM) and the nonlinear FE structural solver is based on the Newton-Raphson method. The capability of the present FSI technique is demonstrated by comparing tip displacements and twist angles of the wing with the available experimental and numerical data in the literature. The effect of wing deformations on the pressure coefficients (Cp) of the linear and geometrically nonlinear wing models is also discussed. It shows that the linear model overpredicts Cp as compared to the geometrically nonlinear wing model. Further, a detailed comparison of span-wise horizontal displacement, vertical displacement, twist distributions as well as lift and side forces is shown between the linear and nonlinear structural models at various flow velocities. Numerical results show significant difference between the linear and nonlinear structural models at higher flow velocities. It indicates that the design of high-aspect-ratio wings must consider FSI approach to capture their nonlinear static aeroelastic behaviour accurately.