Tow tank investigation of developing turbulent boundary layers
Turbulent boundary layers play a large role in dictating the energy efficiency of many engineering systems. Up to 50% of the drag on a modern commercial aircraft is due to turbulent skin friction, and in the case of large ships, this figure can exceed 80%. Together these two industries contribute substantially to global CO2 emissions, hence it is apparent that understanding these fluid phenomena is of vital importance.
In most cases turbulent boundary layers are studied in wind-tunnels or water-channels, at one fixed streamwise location. For this study, a large 5m long flat plate has been constructed, which is towed past a a stationary high-speed measurement system (time-resolved particle image velocimetry), to obtain a unique view of the boundary layer as it develops and evolves downstream of the nose of the vehicle. This unique frame-of-reference is providing valuable insights into the recurrent features / structures that populate high Reynolds number turbulent boundary layers. For an explanation of this facility, and an example of the evolving boundary layer, refer to a recent Gallery of Fluid Motion Movie at the http://arxiv.org/abs/1210.3881
In the future it is hoped that this project can be widened to study the boundary layer developing over rough surfaces and also to investigate flow control methodologies to reduce turbulent skin friction (and hence reduce the energy penalty associated with turbulent boundary layers). In this sense this project will overlap closely with other projects listed by Hutchins and Monty on this database.
PhD students are sought to continue this work.
Leader: Nicholas Hutchins
Staff: Jason Monty
Students: Jung (Will) Lee
Sponsors: Australian Research Council
Optimisation of resources and infrastructure