Abstract: A rotary drill bit having one or more fluid nozzles is provided. Each nozzle may include interior surfaces designed to optimize hydraulic performance and efficiency of fluid flowing through the nozzle. The interior surfaces cooperate with each other to minimize turbulent fluid flow through the respective nozzle. Each nozzle may also include a discharge port or outlet with at least one Coanda surface operable to direct fluid flow in a direction which optimizes efficiency of transferring fluid energy to adjacent portions of a wellbore. The orientation of fluid flow from each nozzle may be directed to optimize cleaning of associated cutting structures and/or to minimize or prevent balling of formation cuttings.