Characterizing Cycle-to-Cycle Variations in Dynamic Stall Measurements

Experimental assessment of an active L-shaped tab for dynamic stall control

“…It is worth noting that the scatter of C M peaks is higher than the C L one, as pitching moment peaks occur at the beginning of downstroke where the flow is highly unsteady. Moreover, analogously to what observed by Ramasamy et al (2016), for the controlled test case 3 the phase-averaged peak of C M underestimates the average of individual cycle peaks by about 10% (see Fig. 7b).…”

“…A more accurate evaluation of the active control performance on airloads peaks were performed by calculating the average of all individual cycle peaks, as described in Ramasamy et al (2016). Indeed, the airloads peaks found from the phase-averaged data can underestimate the values occurring on individual cycles, as they could occur at different angles of attack over the set of pitching cycles considered for the measurements.…”

“…The peak analysis reported in Fig. 12b shows that the phase-average underestimates the pitching moment peak, thus providing a bad evaluation of the L-tab performance (Ramasamy et al, 2016). Indeed, the correct evaluation of C M peaks carried out averaging the individual cycle peaks shows that for case 6 the C M peak is very close to the clean one.…”

Estimation of three-dimensional aerodynamic damping using CFD

“…This variation in recovery angle is the result of cycle-to-cycle differences in the pitching moment coefficient for the quasi-3D SAS simulation. Cycle-to-cycle variations in dynamic stall experimental data has been discussed recently by Ramasamy et al (32) . They analysed two sets of experimental data and found that traditional phase-average filtering is not effective enough to represent dynamic stall load measurements.…”

Analysis of the Unsteady Surface Pressure Distribution of a Pitching Airfoil using Modal Decomposition

“…A similar analysis could be applied to instantaneous results but is beyond the scope of this paper. For a detailed analysis of the cycle-to-cycle variation of the dynamic stall process and instantaneous pressure measurements, the reader is encouraged to consult Ramasamy et al (2018) and Harms et al (2018).…”