Abstract:
In this study, the mandala propulsion process is combined, and the two-dimensional Clark Y airfoil approximation is used to represent the cross-sectional shape of the manta fin and its unsteady hydrodynamic characteristics are simulated. The dynamic hybrid mesh is used to discretize the computational domain. The efficient Delaunay mapping method is used to update the flow field, which avoids the disadvantage that the traditional dynamic mesh method easily generates negative volume. The results of the lift resistance at different upper zone ratios (
p) and maximum pitch angles were obtained by the computational fluid dynamics method. The influence of different
p values on the average lift resistance was refined, and the different maximum pitch angles were compared to obtain the appropriate
p values. The effect on the lift resistance was analyzed. The results show that the average thrust is symmetric with respect to the
p value. Moreover, the standard sinusoidal flapping process (
p=0.5) can produce the maximum average thrust of the movement of the manta fin. The instantaneous maximum thrust is obtained at the equivalent angle of attack of 8.6°. At 0.5 o'clock, the maximum flapping angle is small. Taking 5° makes the average thrust and lift force reach the optimal state, and the corresponding flapping efficiency is 65.1%.