<p>We present the first results from an original experimental setup of a 2D shock wave boundary layer interaction where the separated shear layer does not reattach downstream from the separation. This 2D configuration presents some similarities with the spatial organization of an overexpanded nozzle in the particular case where a Free Shock Separation is observed. Steady and unsteady pressure probes, hot wire anemometry, and particle image velocimetry are used to characterize the spatial organization of the flow and the frequency scales obtained in various configurations. The results are compared with the classical configurations (shock reflection and compression corner). The amplitude of the low-frequency motions is observed to increase when the flow separates in a manner similar to that in classical configurations.</p>