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A comprehensive three-dimensional nonlinear finite element analyses were carried out to examine the effects of the geometry and the incidence angle of canonical 4-lb bird striking a stationary fan blade using LS-DYNA. Three aspects of the work were accordingly examined. The first was concerned with the modeling framework used. The second with the constitutive law that governs the behaviour of the bird. The third was concerned with the influence of the geometry and the angle of incidence of the bird on the integrity of the blade. This article combines and extends the earlier works on both the Lagrangian modeling methodology (Mao et al. AIAA J. Aircr. 44(2), 583-596, 2007) and the bird geometry studies (Meguid et al. 2008) in systematic and integrated manner. Both the bird and the blade were simulated

Lobe-forced mixer is one typical example of the passive flow controllers owing to its corrugated trailing edge. Besides the spanwise Kelvin-Helmholtz vortex shedding, streamwise vortices are also generated within its mixing layer. The geometrical configuration of the lobe significantly affects these two types of vortices, which in turn affects the mixing performance of the mixer. In the present investigation, characteristics of mixers with five different configurations were examined and evaluated for two velocity ratios (r = 1, 0.4). The mixers have only one lobe in order to eliminate any possible interactions between neighboring vortices generated by the adjacent lobes. Hotwire anemometer was used to examine the Kelvin-Helmholtz vortices via the spectrum analysis while laser Doppler anemometer was employed to examine the streamwise vortices. It was found that there were two main frequencies for the Kelvin-Helmholtz vortices in the wake of the mixer; and the Strouhal numbers approached their respective maximum values at high Reynolds number. The rectangular mixer had similar mixing performance with the semicircular one; and both of them were better than the triangular mixer. The scalloping modification enhanced mixing by generating additional streamwise vortices while the scarfing modification could not improve the mixing performance. C I Mean streamwise circulation of the plane I, List of symbolse Penetration angle (half divergence angle) of the lobe-forced mixer k Wavelength of the lobe (m)

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