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These particles are more different to track, hence the tracks are shorter, and the concentration of dye and particles at the center of the front makes it impossible to track the particles for very small radii. Still, it is clear from this plot that the fluid at the frontal surface has the same dependence on radius, although general radial dependence. As expected, at the same radii, these particles have smaller azimuthal velocity than those at the surface. The fluid at the surface is displaced towards the center more than the fluid at lower depths is, therefore in order to preserve angular momentum the surface fluid must acquire greater azimuthal velocity.
5 Challenge: Inverting the Dome!
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