I. Introduction weeping jet heat transfer is relatively new in heat transfer applications such as impingement cooling and film cooling. The development of additive manufacturing techniques has enabled designers to develop compact and integrated devices that can generate unsteady sweeping jets without any active controlling mechanism. A fluidic oscillator is such a device, known for generating an unsteady oscillating jet with no moving parts. The unique sweeping nature of the jet makes it a potential candidate for applications such as flow separation control1, aerodynamic drag reduction2, noise control3 and heat transfer augmentation4-5. A typical wall attachment type oscillator device consists of a power nozzle, two feedback loops, and an exit aperture, or exit nozzle. Figure 1 (a) shows a typical wall-attachment type fluidic oscillator, with the dimensions shown in terms of the throat hydraulic diameter (Dh). The schematic also shows the fan shaped exit nozzle. The general working principle of such a device is as follows. A jet enters into the cavity from a pressurized plenum via the power nozzle, expanding to fill the throat and the feedback channels. Two opposite vortices begin to form on the sides of the power jet because the flow cannot stay attached to the main mixing region walls. As the intensity of the vortices increases, one vortex becomes dominant. This causes the power stream to deflect against the opposite wall (Figure 1b). When the power stream deflects to the side wall, it attaches to the wall due to the Coanda effect. This encourages a portion of the fluid to enter into the feedback loop and flow back to the control port (Figure 1c), causing the power stream to detach from the side wall. The power stream then switches to the opposite wall and the process repeats, resulting in a selfsustaining oscillatory fluid motion at the exit of the nozzle.