Vortex Dynamics in the Sphere Wake
نویسندگان
چکیده
A highly accurate Fourier-Chebyshev spectral collocation method has been used to simulate flow in the wake of a sphere in the Reynolds number range from 350 to 650. Flow visualizations and frequency spectra provide a glimpse of the complex vortex dynamics that are observed in the sphere wake. It is found that in addition to the vortex shedding frequency which corresponds to the shedding of large-scale vortex loops in the wake other lower and higher frequencies are also present and the complex evolution of the vortices in the wake is a result of the non-linear interaction of these frequencies. The response of the sphere wake to flow perturbations is also addressed. Interestingly, it is found that the sphere wake exhibits classic symptoms of the vortex shedding “lock-on” phenomenon which has hitherto been observed mainly in 2-D bluff-body wakes.
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