Flow Separation Studies in a Subscale Truncated Ideal Contour Nozzle

An experimental investigation has been carried out on a subscale truncated ideal contour (TIC) nozzle to study the flow separation phenomena. Tests were made in the P6.2 cold gas subscale facility at DLR Lampoldshausen. Simultaneous wall pressure measurements and surface oil pigment technique was used to study the flow field features at various nozzle pressure ratios. The area-ratio of the nozzle is 20.66 and the test gas is nitrogen. Tests indicate that in a TIC nozzle the main contribution towards side-loads is the pressure pulsation of the flow in the separation region in combination with the flow asymmetry. Separation data also indicates a hyteresis in the Xinc movement during start up and shut down sequences and the circumferential 'rms' distribution indicates a wavy incipient separation line