An efficient system identification approach to estimate unsteady loads on cavitator plates

A new and efficient model for calculation of the unsteady hydrodynamic loads on an oscillating plate in two-dimensional flow is proposed. In order to compute the hydrodynamic loads, an unsteady hydrodynamic model is derived using the boundary-element method along with the potential flow assumption. To this aim, the steady boundary of cavity is determined by a full-nonlinear iterative procedure. Thereafter, assuming that amplitude and frequency of oscillations are so that the length of cavity in unsteady flow remains intact, simulation of the unsteady hydrodynamic flow is performed by imposing some velocity perturbations over the steady cavity solutions. Consequently, based on this formulation, a system identification method is used to obtain a linear model for determination of the applied forces on the plate in unsteady flow. Results obtained using the proposed algorithm are verified. •A novel method is proposed to calculate unsteady loads on a cavitator.•A linear model for unsteady loads is obtained by using system identification method.•Supercavitating flows are captured using the BEM to solve the perturbed equations.•The proposed algorithm is fast and accurate and can be used for design purposes.