Application of oil and dye flow visualization in incompressible turbomachinery flows Alexandros Terzis, Pavlos K. Zachos, Bernard A. Charnley and Anestis I. Kalfas E3S Web Conf., 345 (2022) 02003 Published online: 29 March 2022 DOI: 10.1051/e3sconf/202234502003