Propeller wake flowfield analysis by means of LDV phase sampling techniques

Two phase sampling techniques are developed for the analysis of the propell ers 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 angula r position at the measurement time, is arranged inside angular slots. The o ther technique (ATT) follows an angular triggering method, with some enhanc ements to reduce measurement time. The implemented techniques are complemen tary from the accuracy and efficiency point of view. The TTT enables to qui ckly analyze the propellers wake, in view of the minimization of data acqui sition time, particularly in poor flow seeding conditions. The ATT is inste ad suitable for accurate investigations of space-limited and highly turbule nt flow regions.