On the equilibrium configurations of flexible fibers in a flow

• The problem of a flexible fiber attached to a basal body in a flow is examined.
• The effects of flow, fiber length and initial fiber orientation upon the equilibrium bending of the fiber are studied.
• Experimental observations have been compared with two-dimensional numerical simulations.

We discuss the equilibrium configurations of a fiber clamped to a spherical body and immersed in a flow ranging between 0 and 50 cm/s. Experimental and numerical results are presented and the effects of flow speed and positioning of the fiber upon the equilibrium configuration are investigated. Our investigations reveal that the orientation of the fiber and its length has a significant impact upon its bending and drag experienced by the sphere-fiber system. We note that the longer fibers (i) bend significantly more than the shorter ones and (ii) display oscillatory or flapping motion at much lower flow speeds than their shorter counterparts. The simulations also reveal that the drag on the fiber is noticeably effected by the size of the basal body. Drag exponents (or Vogel exponents) are also computed and seen to deviate slightly from previous results.