Simultaneous Determination of Drag Coefficient and Added Mass

The drag coefficient and added mass (hydrodynamic mass) are the essential parameters for the dynamics analysis of submerged objects with mobility such as bio-mimicking fish robots or underwater vehicles. The shape dependence of these parameters makes them difficult to have good theoretical approximations and the parameters should be determined either numerically or experimentally. Different experiments have been proposed to obtain either the drag coefficient or added mass. This paper presents a new method to simultaneously determine the drag coefficient and added mass from a simple and economic experiment and a numerical identification procedure. An experiment was carried out to demonstrate the method and the identification error was studied analytically and numerically for some experimental uncertainties.