Wave impact on a horizontal elastic plate

Faltinsen, Odd M.; Kvalsvold, Jan; Aarsnes, J

doi:10.1007/bf02491523

Cited by 64 publications

(40 citation statements)

References 3 publications

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“…This problem has been intensively studied experimentally during the last ten years [1,2], numerically [2][3][4][5][6] and theoretically [2,7]. The study carried out by Norwegian researchers is based exclusively on the experiments by Aarsners [1].…”

Section: Introductionmentioning

confidence: 99%

“…In addition to the theoretical analysis already carried out by Faltinsen and his group: we (1) use a modified method of normal modes. After the proposed modifications: calculations of the hydrodynamic loads are not required; the matrix of hydrodynamics coefficients is evaluated analytically; the positions of the contact points are governed by ordinary differential equations, which are incorporated into the system for the principal coordinates of the normal modes; there are no obstacles to start numerical simulations from the initial moment, at which the size of the wetted area is zero; there is no need to introduce the acoustic stage to describe formation of the contact region from a single point; (2) focus on global characteristics of the interaction, which make it possible to explain energy redistribution during the impact and to estimate maximum stress amplitude; (3) consider a range of the problem parameters to reveal peculiarities of the interaction. This may be helpful to design future experiments on elastic-plate impact.…”

Section: Introductionmentioning

confidence: 99%

“…The study carried out by Norwegian researchers is based exclusively on the experiments by Aarsners [1]. Attempts to generalize the derived predictions to other experiments (see, for example, [8,9]) were not done (see [2]). It should be noted that other experiments have not been subjected to such intensive theoretical analysis as the Norwegian ones.…”

Section: Introductionmentioning

confidence: 99%

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Regular wave impact onto an elastic plate

Korobkin

Хабахпашева

2006

J Eng Math

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A computational analysis of an elastic plate dropped against regular long waves is presented. The problem is considered within the linear potential-flow theory. The liquid flow is two-dimensional and the plate is modelled by an Euler beam. The analysis is based on the normal-mode method with hydroelastic behavior of the plate being of main interest. Different impact conditions are considered to study the dependence of the total energy of the plate-liquid system on impact geometry and plate properties. The contributions of kinetic and potential energies to the total energy are analyzed. It is shown that the kinetic part of the system energy is small at the instant of time when bending stresses in the beam approach their maximum values. Estimations of both the total energy and the maximum of bending stresses are presented. Most of the calculations are performed for the conditions of experiments carried out in MARINTEK. A range of the problem parameters is also considered, to reveal peculiarities of the unsteady interaction between a falling elastic plate and surface waves.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Regular wave impact onto an elastic plate

Korobkin

Хабахпашева

2006

J Eng Math

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“…In these papers the vertical impact of an elastic symmetric wedge was addressed using a normal-mode expansion of the body deflection. A similar approach was used in the problem of wave impact onto an elastic plate, as studied by Faltinsen, Kvålsvold & Aarsnes (1997), Korobkin (1998) and Korobkin & Khabakhpasheva (2006). Owing to the elastic deformation of the plate, the contact-point motion and the loads acting on the plate can differ significantly from those for a rigid plate.…”

Section: Elastic-plate Interaction With Water During Impactmentioning

confidence: 99%

Water entry of a flat elastic plate at high horizontal speed

2013

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The two-dimensional problem of an elastic-plate impact onto an undisturbed surface of water of infinite depth is analysed. The plate is forced to move with a constant horizontal velocity component which is much larger than the vertical velocity component of penetration. The small angle of attack of the plate and its vertical velocity vary in time, and are determined as part of the solution, together with the elastic deflection of the plate and the hydrodynamic loads within the potential flow theory. The boundary conditions on the free surface and on the wetted part of the plate are linearized and imposed on the initial equilibrium position of the liquid surface. The wetted part of the plate depends on the plate motion and its elastic deflection. To determine the length of the wetted part we assume that the spray jet in front of the advancing plate is negligible. A smooth separation of the free-surface flow from the trailing edge is imposed. The wake behind the moving body is included in the model. The plate deflection is governed by Euler's beam equation, subject to free-free boundary conditions. Four different regimes of plate motion are distinguished depending on the impact conditions: (a) the plate becomes fully wetted; (b) the leading edge of the plate touches the water surface and traps an air cavity; (c) the free surface at the forward contact point starts to separate from the plate; (d) the plate exits the water. We could not detect any impact conditions which lead to steady planing of the free plate after the impact. It is shown that a large part of the total energy in the fluid-plate interaction leaves the main bulk of the liquid with the spray jet. It is demonstrated that the flexibility of the plate may increase the hydrodynamic loads acting on it. The impact loads can cause large bending stresses, which may exceed the yield stress of the plate material. The elastic vibrations of the plate are shown to have a significant effect on the fluid flow in the wake.

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“…The function p~(x',y',t') is harmonic in the lower half-plane y~ < 0 and is zero at the free boundary by virtue of the dynamic condition. On the segment Ix ~] < L and yJ = 0, after the no-flow condition has been differentiated with respect to time, it gives (Op~/Oy') (x ',O, (x ', t') pVL/T is used for the pressure, and VL for the velocity potential.…”

mentioning

confidence: 99%

Plane linear problem of the immersion of an elastic plate in an ideal incompressible fluid

Korobkin¹,

Хабахпашева²

1999

J Appl Mech Tech Phys

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Introduction. A plane unsteady-state problem of the immersion of an elastic plate of finite length in an ideal incompressible weightless fluid is considered. At the initiM moment (t ~ = 0), the fluid occupies the lower half-plane (yl ~< 0); the segments of its boundary -L < x ~ < L and y~ = 0 correspond to the elastic plate, and the segments z ~ > L, x ~ < -L, and y~ = 0 to the free boundary of the fluid (Fig. 1). The dimensional variables are primed. The plate is hinged to a structure which is being immersed in the fluid with constant velocity V. The impact phenomena, which are connected with the beginning of the motion, determine the initial plate deflection w'(x', 0) and the velocity of its points (Ow'/Ot)(x', 0), which are assumed to be known and are denoted by W~o(X ') and w~(x'), respectively. At the initial stage of immersion, when the structure is displaced to a much smaller extent than the length of the plate, one needs to determine the plate deflection and the distribution of bending stresses in it.The problem is considered within the framework of a linear approximation. The fluid flow is assumed to be plane and potential. The plate is modeled by an Euler beam, and the bending stresses in the transverse direction are assumed to be negligible.The impact by a shallow wave on a plate of finite size is divided into two stages [1]. At the first (impact) stage, the plate is wetted only partially, and the hydrodynamic loads on the plate are great and depend on the rate of expansion of the region of contact between the plate and the fluid. Generally, for shallow waves, this stage is short, and the stresses in the plate do not reach maximum values. At the second stage (immersion), the plate is wetted completely and continues to be immersed in the fluid. Here, the hydrodynamic loads on the plate are already insignificant and cannot be classified as impact. The plate vibrates mainly owing to the potential energy of elastic strains and to the kinetic energy accumulated in the plate during the impact stage. At both stages, the fluid boundary can be replaced by a plane boundary if the wave is quite shallow, and the depth of immersion of the plate is small compared with its size. The last remark explains the problem formulation for the second stage considered in the present work as a problem of immersion of a floating plate in an ideal weightless fluid for which the initial deflection and the velocity distribution are given.

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Wave impact on a horizontal elastic plate

Cited by 64 publications

References 3 publications

Regular wave impact onto an elastic plate

Regular wave impact onto an elastic plate

Water entry of a flat elastic plate at high horizontal speed

Plane linear problem of the immersion of an elastic plate in an ideal incompressible fluid

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