“…(Zachos et al, 2011;Ragni et al, 2011). Measurement techniques and instrumentation have been proposed for turbomachinery applications, either non-intrusively or intrusively, including particle image velocimetry (PIV) (Westerweel et al, 2013), laser Doppler velocimetry (LDV) , laser two-focus method (L2F) (Mousavi and Fahimeh, 2020), hot-wire anemometry (HWA) (Bailey et al, 2010), and multi-hole pressure probes (MHPs) (Heckmeier et al, 2019;Telionis et al, 2009;Argu ¨elles Dı ´az et al, 2009;Crowder et al, 1997). In turbomachinery measurements, the lack of sufficient optical access prevents the use of PIV, LDV, and L2F which are mainly driven by free-space optical techniques.…”