Hydroelastic analysis of water impact of flexible asymmetric wedge with an oblique speed

Abstract

Current paper deals with hydroelastic impact of asymmetric and symmetric wedge sections with oblique speed into calm water. It is aimed to provide a better insight regarding fluid–structure interaction of the wedge sections of a high-speed craft into water in more realistic condition, in the presence of heel angle and oblique speeds. The defined problem is numerically investigated by coupled Finite Volume Method and Finite Element Method under two-way approach consideration. Accuracy of the proposed model is assessed in different steps. The results of current method are compared against previous experimental, numerical and theoretical methods and good agreement is displayed in these comparisons. Subsequently, the method is used in order to examine the fluid and structure behavior during the elastic impact of the wedge into water. Accordingly, four different physical situations are simulated. In the first part, symmetric impact with no oblique speed is simulated. The results of this part show fluctuations in vertical force and pressure of the midpoint during the impact time. Also, the relation of deadrise with deflection and pressure is observed in this part. In the second part, heel angle is also taken into consideration. It is concluded that the pressure and deflections at the right side of the wedge reduce, but these parameters increase at the left side. Moreover, it is observed that, the pressure at the midpoint of the left side of the wedge with deadrise angle of 10°, becomes negative, when the wall of the flexible wedge reaches its largest deflection. It is also observed that, the pressure at left side of the wedge with deadrise angle of 20°, reaches zero. Such behavior does not occur for the wedges of 30° and 45° deadrise angles. In the third part of simulations, oblique water entry of a flexible wedge of 20° deadrise angle is simulated, and no heel angle is considered. Harmonic behavior is observed for the vertical force, horizontal force, pressure of the midpoint and its deflection. First peaks of all of these variables are larger than the second peak. The obtained results lead us to conclude that an increase in oblique speed yields larger deflection and pressure at the right side. Meanwhile, no significant effect is observed for the left side of the wedge. Also, larger oblique speed is found to yield larger forces and angular moment. Final part of simulations involves the oblique water entry of a flexible wedge of 5° heel angle. Comparison of the results in the final part with that of third part, show that heel angle affects the pressure and deflection at both sides of the wedge. It is also observed that pressure and deflections of the left side increase, while those of right side increase. It is also seen that, similar as in the case of no heel angle, an increase in oblique speed leads to an increase of pressure and deflection at the starboard. It also leads to an increase in frequency of the vibration at right side.