An argon radio frequency -RF- atmospheric pressure plasma jet for biomedical applications is investigated regarding its laminar and turbulent flow regimes. Additionally, the influence of the gas curtain around the plasma jet effluent on the global flow is studied. By using planar laser-induced fluorescence -PLIF- technique on tracers, observations of flow pattern with and without plasma are possible for different flow rates. The transition between laminar and turbulent is determined experimentally since the classical Reynolds number approach may be not suitable to our plasma features. Simultaneous acquisitions of PLIF signal and argon emissions from the streamer are in excellent agreement and it is shown that streamer and turbulent gas flow have an identical path.