Series of animations showing the time evolution of the flow field around an oscillating no-slip sphere in an incompressible fluid for various driving frequencies ω (in units of τa−1 = ν/a2, where a denotes the sphere radius and ν the kinematic viscosity of the fluid). Streamlines (black lines with arrow heads) indicate the direction of the velocity field and the color coding its magnitude. Amplitudes of the driving force (F) acting on and the velocity (v) of the sphere are shown as red and blue arrows within the white sphere.
Related publication: Y. von Hansen, A. Mehlich, B. Pelz, M. Rief & R. R. Netz, "Auto- and cross-power spectral analysis of dual trap optical tweezer experiments using Bayesian inference", Rev. Sci. Instr. 83, 095116 (2012), link
ωτa=10-5 ωτa=10-4 ωτa=0.001 ωτa=0.01 ωτa=0.1 ωτa=1 ωτa=10