Bifurcation Point Analysis of Airfoil Flutter with Structural Nonlinearity

This chapter presents a further investigation of nonlinear flutter of an airfoil in incompressible flow due to structural nonlinearities. The emphasis is placed on the characteristics of bifurcation points of the flutter system. The center manifold theory is used to reduce the dimension of the system under investigation. The type and stability of the bifurcation points in the subsequent reduced two-dimensional system are then analyzed by two methods: the method of succeeding function and the method of formal series. It is concluded that the bifurcation points are not centers but stable or unstable foci. The physical meanings and engineering applications of the obtained results are discussed.