The time-resolved internal and external flow field of two common oscillator designs with equal outlet diameters are acquired by employing PIV measurements and phase-averaging the results. The investigation of the flow fields and pressure measurements reveals the same underlying oscillation mechanism for both designs. The curved oscillator does not incorporate the change of the internal dynamics as observed for the angled oscillator. The oscillation frequency is similar and solely depends on the geometry-specific total volume transported through the feedback channels. The different mixing chamber geometry of the curved oscillator requires a larger recirculation bubble for the jet to attach to the other wall and prevents the reverse flow through the feedback channels which is found in the angled oscillator. Separation bubbles inside the corners of the angled oscillator are avoided by the streamlined feedback channel geometry of the curved oscillator. The required supply pressure infers a superior general performance of the curved oscillator in terms of energy requirements. Contrary to the angled oscillator, the curved oscillator’s jet attaches to the walls of the outlet nozzle’s diverging part which causes a higher maximum deflection angle and a different oscillation pattern in the external flow field. The distribution of fluid in the external flow field reveals significant differences between the designs. Similar characteristic vortices are identified in both flow fields. The curved oscillator yields slightly more entrainment than the angled oscillator. The entrainment is affected little by maximum deflection angle and oscillation pattern.