The fundamental mechanism of turbulent wedge spreading is investigated using combined naphthalene flow visualization and hotwire measurements. The lateral spreading rate of turbulent wedges is remarkably constant throughout the literature but the spreading mechanism remains unclear. Recent work has investigated the role of high- and low-speed streaks in lateral spreading. A streak self-regenerating mechanism is proposed to be responsible for turbulent wedge spreading as streaks are successfully regenerated along the sides of a wedge. The low-speed streak breakdown then propagates turbulence to the surrounding laminar flow. The objective of this work is to experimentally document the emergence of high- and low-speed streaks and their role in turbulent wedge spreading. In addition, spanwise streak meandering is investigated.
展开▼
