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Nous avons mesuré les efforts exercés sur un cylindre horizontal près du fond par l'action de la houle se propageant vers la côte. Celle-ci est modélisée par une plage de pente constante qui va induire une déformation progressive de la houle. Les efforts mesurés sont influencés par la hauteur et la dissymétrie de la houle ainsi que par l'écartement du cylindre par rapport au fond. Une modélisation de l'effort en ligne par la formulation de Morison est également menée et les coefficients hydrodynamiques correspondants sont présentés. Nous montrons ainsi que l'emploi d'un modèle simplifié de la vitesse horizontale, prenant en compte la dissymétrie de l'écoulement, permet d'étendre la validité du modèle de Morison aux houles pré-déferlantes. Abstract We have measured wave forces on a horizontal cylinder near the seabed in the coastal zone. A beach of constant slope induces the progressive wave deformation. The measured forces are influenced by the wave heig..'1t, the wave asymmetry and the distance between the cylinder and the bottom. Modelling of the in-line force using the Morison formulation is also performed and the resulting hydrodynamic coefficients are presented. We show that the use of a horizontal velocity model taking into account the flow asymmetry enables to extend the validity of the Morison model to shoaling waves.

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For axisymmetric extrusion through conical dies, an admissible velocity field without discontinuities was obtained by superposition of basic flow patterns. Based on this velocity field, the upper bound to the average forming pressure and the detailed mechanics were calculated for the extrusion of a rod with a semi-cone angle of 45° and a reduction of 75 per cent in area. Three different friction conditions along the die were considered and their influence on the deformation characteristics was discussed. Flow lines, velocity components, grid distortion, strain-rate components, effective strain rate, effective strain, and stress components were plotted. A comparison of the present results with those obtained experimentally (visioplasticity) shows good agreement.

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