Effect of bubble distribution on wall drag in turbulent channel flow

摘要

Skin-friction drag reduction in (water) turbulent boundary layers using bubble injection has been studied for some time. Ceccio (Annu Rev Fluid Mech 42:183-203, 2010) and Murai (Exp Fluids 55(7):1-28, 2014) have compiled drag reduction data from a number of different studies and facilities, and highlighted the large differences and scatter in the data even at the same bubble void fraction. Motivated by this, in the present work, we experimentally investigate within a single horizontal turbulent channel facility, drag modification using bubbles over a wide range of bubble void fraction (0