Using ANSYS-CFX, a general purpose fluid dynamics program, the vortex-induced vibration(VIV) of a variable cross-section cylinder is simulated under uniform current with high Reynolds numbers. Large eddy simulation(LE...Using ANSYS-CFX, a general purpose fluid dynamics program, the vortex-induced vibration(VIV) of a variable cross-section cylinder is simulated under uniform current with high Reynolds numbers. Large eddy simulation(LES) is conducted for studying the fluid-structure interaction. The vortex shedding in the wake, the motion trajectories of a cylinder, the variation of drag and lift forces on the cylinder are analyzed. The results show that the vortices of variable cross-section cylinder are chaotic and are varying along the cylinder. In places where cross-sections are changing significantly, the vortices are more irregular. The motion trail of the cylinder is almost the same but irregular. The drag and lift coefficients of the cylinder are varying with the changes of diameters.展开更多
A localized flexible airfoil at low Reynolds numbers is modeled and the aerodynamic performance is analyzed numerically.With characteristic based split scheme,a fluid solver for two dimensional incompressible Navier-S...A localized flexible airfoil at low Reynolds numbers is modeled and the aerodynamic performance is analyzed numerically.With characteristic based split scheme,a fluid solver for two dimensional incompressible Navier-Stokes equations is developed under the ALE framework,coupled with the theory of shallow arch,which is approximated by Galerkin method.Further,the interactions between the unsteady flow and the shallow arch are studied in detail.In particular,the effect of the selfexcited vibration of the structure on aerodynamic performance of the airfoil is investigated deeply at various angles of attack.The results show that the lift-to-drag ratio has been increased greatly compared with the rigid airfoil.Finally,the relationship between the self-excited vibration and the evolution of the flow is analyzed using FFT tools.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 51179179 and 51079136)
文摘Using ANSYS-CFX, a general purpose fluid dynamics program, the vortex-induced vibration(VIV) of a variable cross-section cylinder is simulated under uniform current with high Reynolds numbers. Large eddy simulation(LES) is conducted for studying the fluid-structure interaction. The vortex shedding in the wake, the motion trajectories of a cylinder, the variation of drag and lift forces on the cylinder are analyzed. The results show that the vortices of variable cross-section cylinder are chaotic and are varying along the cylinder. In places where cross-sections are changing significantly, the vortices are more irregular. The motion trail of the cylinder is almost the same but irregular. The drag and lift coefficients of the cylinder are varying with the changes of diameters.
基金This research is supported by Program for New Century Excellent Talents in University in China,No.NCET-07-0685.
文摘A localized flexible airfoil at low Reynolds numbers is modeled and the aerodynamic performance is analyzed numerically.With characteristic based split scheme,a fluid solver for two dimensional incompressible Navier-Stokes equations is developed under the ALE framework,coupled with the theory of shallow arch,which is approximated by Galerkin method.Further,the interactions between the unsteady flow and the shallow arch are studied in detail.In particular,the effect of the selfexcited vibration of the structure on aerodynamic performance of the airfoil is investigated deeply at various angles of attack.The results show that the lift-to-drag ratio has been increased greatly compared with the rigid airfoil.Finally,the relationship between the self-excited vibration and the evolution of the flow is analyzed using FFT tools.
