Science Alert  February 6, 2024 The issue of reversibility in hydromechanical sprinklers that auto-rotate while ejecting fluid from S-shaped tubes raises fundamental questions that remain unresolved. Through experiments a team of researchers in the US (New York University, Colorado School of Mines) has shown robust and persistent reverse rotation under suction and developed a model that accounted for the observed motions. They implemented an apparatus that allowed for free rotation under ejection and suction for a range of flow rates and arbitrarily long times. Flow measurements revealed a rocketlike mechanism shared by the reverse and forward modes that involved angular […]