Propeller wake flowfield analysis by means of LDV phase sampling techniques

Two phase sampling techniques are developed for the analysis of the propellers wake by means of LDV. The first one (TTT) uses the detection of Doppler signal as trigger condition; each LDV sample, tagged with the blade angular position at the measurement time, is arranged inside angular slots. The other technique (ATT) follows an angular triggering method, with some enhancements to reduce measurement time. The implemented techniques are complementary from the accuracy and efficiency point of view. The TTT enables to quickly analyze the propellers wake, in view of the minimization of data acquisition time, particularly in poor flow seeding conditions. The ATT is instead suitable for accurate investigations of space-limited and highly turbulent flow regions.