Fig. 4
Experimental apparatus and diagnostics. a Schematic of the modified Taylor-Couette device48, with the inner and outer cylinder radii of r1 = 6.9 cm and r2 = 20.3 cm, respectively, and the height of h = 39.7 cm. The device was filled with water to a depth of 31.1 cm and the top was open to allow access. A GoPro HERO4 camera was partially submerged to minimize optical distortion. The camera was supported by an attachment and co-rotated with the ring (yellow) at Ω3. A 1-inch-diameter neutrally buoyant test mass (red) was tethered by an unstretched spring to a vertical post and held by a spring-loaded jaw-clamp. At t = 0 a release line (not shown) was pulled from above allowing the vertical spring to relax, releasing the mass. b Photograph of the test mass and release mechanism. The camera is visible at the top of the image
