- Air Wakes and Rotorcraft
Helicopter landings onto small platforms and ships are extremely challenging and dangerous. As a wind crosses over a ship it produces significant turbulent fluctuations which add greatly to pilot workload. Coupled with a severe mean flow, landing on a ship is one of the most dangerous scenarios a helicopter pilot can face. Research within the FLuD group aims to substantially improve the knowledge of the complex flows produced as a helicopter approaches to land, in collaboration with DSTO. This involves the development of helicopter blade models, advanced unsteady turbulence modelling coupled with the high order accurate algorithms in our USyd and open source CFD packages.
The image illustrates the complex vortical structures resolved in an LES of a Royal Navy vessel.
As a fluid passes over an open cavity it naturally produces noise, most commonly experienced when you open a car window. In aeronautical applications, a similar mechanism causes very high noise levels in wheel bays, optical bays, or weapons bays. These high levels of noise can be substantial enough to cause damage to structures and systems within the cavity. Research into multiple cavity configurations and applications is under way within the FLuD group together with industry partners, with an aim to improve understanding of more complex cavity shapes at a range of Mach and Reynolds numbers.
A visualisation of a complex flow-acoustic interaction over a deep cavity at Mach 0.8 is shown
Hypersonic flows pose unique challenges in both physics and numerical methods. The FLuD group has both DSMC and CFD capabilities to tackle rarefied and continuum flows at hypersonic speeds. On the continuum side this includes studies of the flow physics of high speed intakes with real gas equations of state, and shock-boundary layer interaction. DSMC methods were developed first at the University of Sydney and have been applied to rentry vehicles, micro-fluidic systems and general high Knudsen Number problems.
Reentry flow for a sphere at Mach = 9.9 is shown.