Flexible Fibres in Wall-Bounded Turbulence

Abstract We study the dynamics of flexible fibres in turbulent channel flow by performing DNS in an Euler-Lagrange framework. We use the rod-chain model to construct fibres by linking sub-Kolmogorov rods. Jeffery 1 gave the expression describing the rotation executed by ellipsoids suspended in a viscous simple shear flow devoid of fluid inertia. We use Jeffery’s expression to calculate the orientation of the suspended rods. In addition, to account for the role of the fluid inertial forces and torques, we use the model by Dabade et al. 2. Subsequently, we perform a set of direct numerical simulations of a fibre-laden channel flow whose shear Reynolds number is 300, for a range of fibre parameters to specifically discern the effects of the fibre length, their flexibility characterised by their bending stiffness, and the inclusion of fluid-inertial forces and torques.