The hydrodynamic characteristics of six scallops of the Super Family Pectinacea, Class Bivalvia

Abstract

Measurements have been made in a recirculating water channel of the lift and drag forces on the plaster casts of six scallops of the Super Family Pectinacea, Class Bivalvia, namely Chlamys varia, Amusium pleuronectes, Pecten irradians, Pecten senatorius, Pecten pallium and Pecten alba. The results have shown that the shape of the lift curve for the bi-convex shells is similar to that of a comparable aerofoil shape, a discus, although with lower values. The piano-convex shell had similar lift values but a lower stall angle. All the shells produced more induced drag than the discus and also had a higher form drag. Generally there was a correlation between the form drag coefficient and the thickness to chord ratio of the shell. It is suggested that Amusium pleuronectes would be the best adapted for swimming flight, because of its low drag characteristics, followed by Pecten senatorius and Pecten irradians. It is thought that, although Pecten alba was likely to be the worst swimmer of those tested, it was also likely to be best able to escape by its ability to develop lift.