FIGURE 5 Time histories of Cl and Cd for CA models with same frequency. The flapping was set to downstroke firstly and then upstroke. Where, the downstroke is indicated by the shaded area. (a-c) theCl of AP1 is always the highest at the three flapping frequencies. (d-f) the Cd of the AP1 is the highest at the low-frequency flapping (55 Hz). With the increase of the flapping frequency, the Cd of the AP1 begin to fall.
Table 2 The average Cl(l ), average Cd (l ) and averageCl/Cd(\(\overset{\overline{}}{C_{l}/C_{d}}\)) of CA models at different flapping frequencies