Figure 2: Soap-film experiments of a freely hanging body.
From: Passive appendages generate drift through symmetry breaking
(a) Schematic of the soap-film apparatus and the hanging mechanism for the cylinder with a splitter plate. The object is attached to a nylon wire at the cylinder centre. The nylon wire is then connected on both sides to a fixed rod. If the cylinder with a splitter plate experiences a drift force Fd, the object drifts away from the centre position until it reaches equilibrium with gravitational force (see Methods: Soap-film experiments of a hanging body). (b) For a low flow velocity we observe a straight, symmetric position of the plate (depicted with red line). (c) For a high flow velocity, the object turns and drifts to the right. (d) Experimental observation of the force angle versus the length of the splitter for a velocity υ=2.0 m s−1 (red dots). Model predictions in blue with parameters Bmax=2.6D and k=1.0.
