Further contributions to the dynamics of a freely rotating elliptical particle in shear flow

In this study, the dynamic response of a neutrally buoyant elliptical cylinder is investigated for a two-dimensional shear flow over a wide range of aspect ratios (rb=ra, where, ra and rb are the major and minor axis radii, respectively). Parametric studies were carried out for confinement ratios (k 1/4 2ra=H) that vary the distance between the particle and the domain walls (H) for shearrate (G) based Reynolds number (Re 1/4 r(2)aG.f =mu f ) : The simulations were performed using the signed distance field-immersed boundary method (SDFIBM) algorithm implemented in OpenFOAM. The motion of the particle is limited to free rotation about the z axis through the centroid without any translational freedom. This work demonstrates and affirms two distinct responses of the elliptical particle in shear flow: (1) a periodical rotating stage that exhibits a relaxation type of response and (2) a spontaneously locked stationary stage, where the net torque becomes zero. A critical Reynolds number (Recr) demarcates the transition between these two stages, and it depends on aspect ratio and confinement ratio. The prediction of Recr was found to be in excellent agreement with the experimentally reported data in the literature, validating the SDFIBM for particles subjected to shear flows.

Automated summary

This study investigates the dynamic response of a neutrally buoyant elliptical cylinder in shear flow, revealing two distinct responses and discussing the transition between them through the prediction of a critical Reynolds number. The findings validate the effectiveness of the SDFIBM method for particles subjected to shear flows.