The present paper exposes the current research work carried out at LABORATOIRE DE THERMOCINE´TIQUE de NANTES within the framework of a collaborative research with DCN PROPULSION concerning the design of nuclear structures subjected to dynamic loading. The case under study consists of a cylinder strongly accelerated from rest in an infinite fluid medium. The main aim of the study is to predict forces acting on the cylinder and to provide a clear description of the flow phenomena. The duration of the mechanical impulse imposed on the cylinder is extremely short (of the order 15 milliseconds). The level of acceleration is 30 times the gravitational acceleration. These operating conditions are representative of a typical shock encountered in the environment of a military ship. This work is composed of a numerical and an experimental part. The numerical modeling is developed in a finite volume formulation. The cylinder is moved inside the computational domain using the ALE formulation for the moving mesh grid. Well-documented experiments on a cylinder impulsively started from rest are simulated to test the numerical procedure and validate our code. Then shocks with sinusoidal acceleration are simulated and compared with the theoretical model of Stokes. The experimental part presents the set-up currently under construction in the laboratory. The cylinder is put in motion by a hydraulic accelerator connected to a power hydraulic station and driven by a computer-controlled servo-valve. The metallic bar holding the cylinder is equipped with strain gauges measuring the integral forces acting on the cylinder.

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