The performances of liners employed to reduce noise emissions, for example in nacelles of aircraft engines, are usually characterised by the acoustic impedance of the material. If this concept is well-defined without flow, this is not the case in presence of flow. Indeed, on small test-rigs, differences have been observed in presence of grazing flow between the impedance measured for the acoustic plane waves traveling in the direction of the flow and the one measured for waves travelling in the opposite direction of the flow. Thus, a new and larger test-rig has been built to investigate, among other goals and studies, if these differences are also observed for propagating modes beyond the plane wave. This facility is called MAINE Flow, for Multimodal Acoustic ImpedaNce Eduction with Flow and is a rectangular duct of section 150 x 280 mm with an acoustic field up to 150 dB and a grazing flow up to M=0.6. An important characteristic of the new test-rig is that it can measure the liner acoustic properties for different acoustic modes independently of each other. Furthermore, it can be used to qualify liners and innovative acoustic treatments in flow and acoustic conditions close to flight conditions and thereby asses their maturity for use in real conditions. We will display here the results of the validation studies performed on this new test bench, in particular concerning the modal control allowing to force the duct modes independently. The first liner measurements will also be shown, for few flow velocities and multiple incident acoustic fields.