Turbulent jets are widely used in industrial applications such as propulsion, flow control and heat transfer enhancement. Among the various jet configurations, sweeping and precessing jets have attracted increasing attention due to their unsteady behaviour and their ability to promote flow entrainment and mixing. This thesis investigates the flow field and heat transfer performance of impinging sweeping jets, focusing on the effects of the nozzle-to-plate distance and key geometric parameters of the fluidic oscillators. Building on these results, a novel approach is proposed to stabilize the precession of a conventional precessing jet by introducing helical feedback channels wrapped around the mixing chamber. The flow field of the resulting free precessing jets, as well as their heat transfer performance in the impinging configuration, are experimentally investigated. Finally, a parametric analysis is carried out to assess the influence of the angular displacement between the inlet and outlet sections of the feedback channels.