Citation:
Saddington AJ, Knowles K, Cabrita PM. (2009) On the characteristics of a twin-jet STOVL fountain. The Aeronautical Journal. Volume 113, Issue 1140, February 2009, pp. 139-148.
Abstract:
The interaction of multiple jets with the ground is of
great importance for the design and operation of short
take-off, vertical landing aircraft. The fountain upwash
flow, generated by the impingement of two axisymmetric,
compressible, turbulent jets onto a ground plane
was studied using laser-based particle image velocimetry
and laser Doppler velocimetry. Measurements
were made with nozzle pressure ratios of between 1.05
and 4, nozzle height-to-diameter ratios of between 2.4
and 8.4, nozzle splay angles of between 15 degrees
and a nozzle spacing-to-diameter ratio of seven. The
effect of varying these parameters on the fountain velocity
decay, spreading rate and momentum flux ratio
are discussed. Mean fountain upwash velocity profiles
were found to be self-similar for all test conditions. A
distinct frequency of fountain oscillation was identified
but only at a nozzle height of 4.4 diameters.
