Drag reduction in pipe flow holds significant importance due to its potential for reducing energy consumption in the transportation of gases or liquids, thereby leading to decreased pollutant emissions into the atmosphere. While the potential of pipe rotation for frictional drag reduction has been recognized since early experiments, these were hampered by severe technical complications. Similarly, numerical simulations were limited to modest Reynolds numbers.
In recent studies, noteworthy discovery has been made that, unlike in other friction reduction techniques, the friction coefficient in rotating pipe flow actually decreases with the Reynolds number, for a given rotational speed. Observations gather that drag reduction as large as 70%, marking a significant advancement with promising implications for practical technological applications. In this research, the objective is to extend investigations into the Reynolds number range typical of realistic pipelines. By doing so, the project aims to construct a comprehensive map of drag reduction as a function of Reynolds number and verify the reliability of finite-Reynolds-number extrapolations.
Sergio Pirozzoli, Sapienza University of Rome, Italy