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Abstract: The problem of an elastic lifting hydrofoil in a randomly perturbed flow is considered. It appears that in these conditions the phenomenon of hydroelastic-induced vibrations is controlled by a stochastic differential operator. By using the theory of stochastic perturbation, a technique of solution for this class of problems is proposed, leading to an effective numerical solution. The fundamentals of the method are given and it is applied to the general problem of hydroelastic vibrations. A numerical application to the case of an elastic control surface for a prototype-high- speed marine vehicle is presented. Comparisons between the results obtained by the Stochastic Perturbation Method (SPM) and those provided by standard Monte Carlo simulations (MCS) show the accuracy of the proposed method and a useful saving in computational time. A method is given for comparing the computational time required by the two methods, for a given statistical accuracy. [Copyright &y& Elsevier]

The aim of this paper is to provide a theoretical and experimental analysis of the response of an elastic system carried on board a wedge-shaped body impacting the water surface. The wedge entering the water has a sudden deceleration with shock characteristics, resulting in a short-time duration and a sharp peak value. On the other hand, the carried system undergoes an oscillatory motion induced by the inertial load generated by the impact. The study of this problem reveals the occurrence of special conditions in the response of the on-board oscillator, depending on the parameters associated with the water entry problem, that lead to large elastic forces. The experiments show that when varying the characteristic natural frequency of the on-board oscillator, critical impact conditions occur characterized by very large amplitudes of the structural response that confirm the theoretical predictions. The analysis, based on the water shock spectral response developed by the authors in some previous papers, is generalized here and validated experimentally. [Copyright &y& Elsevier]