Table 2.

Dimensionless numbers at low and high flight speeds

		Flight speed U (m s⁻¹)
		4	11
Reynolds number	Re=Uc/v (×10⁴)	1.3	3.5
Reduced frequency	k=πfc/U	0.53	0.19

c, mean chord; v, kinematic viscosity; f, wingbeat frequency.