No abstract

An investigation into the effect of inlet boundary conditions choice on the solution of the time-averaged Navier-Stokes equations together with a k-6 turbulence model has been carried out for a two-dimensional internal ventilation flow. The study shows that for large ventilation areas, with associated velocity gradients, the assignment of turbulence parameters has a substantial effect on the solution.

The L1d computational fluid dynamics code is used to model numerous shock tunnel facilities worldwide. A number of free-piston driven shock tunnel facilities, such as the T4 Stalker tube at the University of Queensland, utilises a piston-braking system to prevent facility damage. However, the braking system may have some effects on the piston dynamics during operation. The L1d code currently does not account for the brake dynamics and the friction force created through the piston-brake interface. It was hypothesised that including this may lead to more accurate predictions, which would benefit any institution that models shock tunnel facilities using a piston-brake system. This thesis developed a numerical model to understand the piston-brake dynamics. The model was validated against L1d for a configuration neglecting brake dynamics. The model was then used with brake dynamics to investigate the effect on piston motion for numerous shock tunnel flow conditions and friction coefficient configurations. Simulations suggested that the friction force generated by the brakes had a slight effect on the piston motion, but was too insignificant to warrant including it in the L1d code.