Minimum sustainable drag for constant volume-flux pipe flows

Abstract

Comparisons are made between laminar and turbulent flows in pipes with and without flow control, and a formula is derived that shows just how much the discrepancy between the volume flux of laminar and turbulent flow at the same pressure gradient increases as the pressure gradient is increased. Related to this, we investigate the lowest bound for skin-friction drag in pipes for flow control schemes that use surface blowing and suction with zero-net volume-flux addition. © 2008 Springer.