A nonlinear analysis framework for bluff-body aerodynamics: From navier-stokes equations to volterra systems

The origin of nonlinear aerodynamics involved in wind-structure interactions represented by the Navier-Stokes equations is first investigated. Computational approaches employed in this study are validated through theoretical consideration, Blasius solution for the steady-state simulation and Theodorsen solution for the dynamic-state simulation. A nonlinear analysis framework for bluff-body aerodynamics based on Volterra theory is utilized to capture the linear and nonlinear aerodynamic effects. The Volterra kernel identification is based on the impulse function concept which is illustrated through computational fluid dynamics. The simulation results based on this reduced-order modeling scheme is obtained by the convolution of the identified kernels and the external inputs. It is demonstrated that the Volterra theory based nonlinear analysis framework of bluff-body aerodynamics is promising in capturing the essential features of bluff-body aerodynamics and offers an accurate approximation of the Navier-Stokes equations with minimal computational effort.