Why Curling Stones Curl: Modelling and Numerical Experiments

Abstract

In curling, a sport played on ice, players release stones on the ice sheet at initial speeds of translation and rotation aiming to a target location with curled trajectory. To elucidate why the stones curl, we focus on the fact that asperities on the leading and trailing parts of the bottom of stone pass through the same spot on the ice surface twice within a short period of time. We also consider the fact that the ice is at a very high temperature close to its melting point and the recovery from the damaged state after the microscopic fracture and plastic deformation by the friction takes place quickly. Theoretical models for the magnitude and direction of the friction force between the stone and ice are developed and the motion of the stone was numerically analysed. Contribution of several factors that may be involved in friction on ice surfaces was investigated in detail. Analysis results were compared with experimental ones in literature and some were found to be in good agreement.