A CFD/CSD model for aeroelastic calculations of large-scale wind turbines

In this paper, a CFD/CSD model coupling N-S equations and structural equations of motion in the time domain is described for aeroelastic analysis of large wind turbines. The structural modes of blades are analyzed with one-dimensional beam models. By combining point matched sliding grid for wind turbine rotation and deforming grid for structural vibrations, a hybrid dynamic grid strategy is designed for the multi-block structured grid system of a wind turbine. The dual time-stepping approach and finite volume scheme are applied to the three-dimensional unsteady preconditioned N-S equations, and DES approach is employed to simulate the unsteady massively separated flows. A modal approach is adopted to calculate the structural response, and a predictor-corrector scheme is used to solve the structural equations of motion. CFD and CSD solvers are tightly coupled via successive iterations within each physical time step. As a result, a time-domain CFD/CSD model for aeroelastic analysis of a large wind turbine is achieved. The presented method is applied to the NH1500 large wind turbine under the rated condition, and the calculated aeroelastic characteristics agree well with those of the prescribed vortex wake method.