Vortex-Induced Asymmetric Loads on Slender Vehicles PDF Download

Author: Lars E. Ericsson
Publisher:
ISBN:
Category :
Languages : en
Pages : 237

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Book Description
The steady and unsteady vortex-induced asymmetric loads on slender vehicles were investigated. The study reviewed pertinent two- and three-dimensional data; developed analytic means for predicting the upper limit for vortex-induced asymmetric loads; and assessed the importance of these loads to the vehicle dynamics of slender bodies of revolution. The study showed boundary layer transition to have a dominant influence on static and dynamic vortex-induced loads. The predicted upper limit for vortex-induced asymmetric loads bounds all available experimental data from subcritical to supercritical Reynolds numbers. The most powerful dynamic effect is that of the moving wall at the separation point, which has a wall-jet-like effect on the boundary layer separation and transition. Preliminary experimental results indicate that because of this effect the dynamic stability parameters due to pitching and coning can be one order of magnitude larger than those occurring in attached flow at lower angles-of-attack. A very important effect of asymmetric vortices existing at high angles-of-attack is to provide a coupling mechanism at zero sideslip between longitudinal and lateral degrees of freedom. As these cross coupling effects are very large, highly nonlinear, often discontinuous and associated with hysteresis effects, with especially large impact on the vehicle dynamics, they are of great concern to missile and aircraft designers.