Experimental hot-wire characterisation of the turbulent jet produced by a sweeping jet actuator in a quiescent environment

Abstract

The present work presents the design and the characterisation of a sweeping jet, a fluidic actuator that has been shown to be able to enhance the aerodynamic performance of flow applications as transportation vehicles. The principles and operation of this type of actuator are detailed here. An experimental apparatus with hot-wire anemometry was installed to describe the flow topology produced by the sweeping jet. Basic analysis shows that the jet generates a flow with an average velocity of 60<Umean<100ms−1, a flow rate between 1.3 and 3 gs−1, and an oscillating frequency up to 2200Hz. The produced jet geometry is also analysed and shows interesting behaviour. The evolution of geometrical parameters is influenced by a transonic transition inside the actuator. To analyse the turbulent properties of the external flow, spectral triple decomposition is developed and used on the experimental data. A strong impact of the transition from a subsonic to a transonic regime on the produced flow is highlighted. The analysis of the turbulence produced by the sweeping jet shows a separation of the flow in three different zones detailed in the article. The study highlights promising results for future flow control implementations.