Abstract:
During wind tunnel testing of jet-lift, short take-off and vertical landing (STOVL)
aircraft it is usual to simulate the jet efflux but not the intake flows. The intakes,
which are commonly faired over or are unpowered, are generally tested in separate
wind tunnel experiments. The forces acting on the wind tunnel model are determined
by the linear addition of the forces obtained from the two separate tests.
There is some doubt as to whether this is a valid approach.
A systematic experimental investigation was, therefore, conducted to determine the
magnitude of any jet/intake interference effects on a generic jet-lift STOVL aircraft
in transitional flight, out of ground effect. Comparisons made between separate and
simultaneous jet and intake testing concluded that a mutual jet/intake interference
effect does exist. The existence of this interference means that the aerodynamic wing
lift loss in transitional flight deduced from isolated jet and intake testing is less than
the lift loss obtained from simultaneous jet and intake testing.
The experimental research was supplemented by some simplified computational
fluid dynamics (CFD) studies of elements of the flow-field about the aircraft using
the k-e turbulence model. The numerical modelling enabled aspects of the flow-field
around the aircraft to be visualised which could not easily be done using the experimental
apparatus.
It is a requirement of the Eng]) programme that part of this thesis must address a
management topic linked to the research. In this case the management aspects of
wind tunnel project work were examined. A scenario was developed which established
a requirement for a large-scale, low-speed wind tunnel with a Reynolds number
capability of 20 million. A study was performed on the decision-making process
and investment appraisal methods used in the procurement of such a wind tunnel.
