Inclined turbulent fountains

We present an experimental investigation of turbulent fountains produced when dense fluid is injected upwards into either a homogeneous or a stratified environment at an angle to the vertical. We determine the initial height above the source at which the flow first comes to rest, the final height of the fountain, and the height at which the mixed fluid finally intrudes when the environment is stratified. The initial fountain height is found to decrease monotonically as the angle of inclination is increased. In contrast, the final fountain height is found to increase and then to decrease, with the maximum height occurring at an angle of inclination of about 10°. This behaviour is due a combination of the decreased interaction between the upflow and the downflow, and the decreased vertical momentum of the injected fluid, as the angle of inclination is increased.