... to travel a unit distance, or cost of transport (COT), has a U -shaped relationship to speed. The relationship between propulsive kinematics and speed, summarized by the Strouhal number ( St = fA / U , where f is tail beat frequency, A is tail tip amplitude in m and U is swimming speed in m s −1 ), allows...

..., the dynamic similarity between the model flight and actual insect flight was measured using not only the non-dimensional numbers for the fluid (the Reynolds and Strouhal numbers) but also those for the fluid—structure interaction (the mass and Cauchy numbers). A difference was observed between the mass number...

...) and V , or downstroke ratio (the duration of the downstroke divided by the total stroke period) and V. On the other hand, SR decreases significantly with increasing wing beat frequency f , SR ∝ f -0.40 . The Strouhal number ( St=f ×amplitude/ V ), a dimensionless parameter describing oscillating flow...

... against the surrounding medium. The theory predicts additional features of animal design:the Strouhal number constant, which holds for running as well as flying and swimming, the proportionality between force output and mass in animal motors,and the fact that undulating swimming and flapping flight occur...

... to as a Strouhal number, which for the range between 0.20 and 0.40 has been associated with enhanced swimming efficiency for fish and cetaceans. Yet to date there has been no direct experimental substantiation of what Strouhal numbers are preferred by swimming cetaceans. To address this lack of data, a total...