Free Elastic Plate Impact into Water

Reinhard, Moritz (2013) Free Elastic Plate Impact into Water. Doctoral thesis, University of East Anglia.

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The Wagner theory, developed 80 years ago, is an analytical method for solving problems
where a body with small deadrise angle impacts onto an undisturbed water surface of infinite
depth. In this study, two-dimensional impact models based on the Wagner theory are
developed which account for the elasticity of the body, for large horizontal speed of the body
and flow separation from the body.
In chapter 3, the problems of inclined rigid and elastic plates, impacting the fluid vertically,
are solved. The elastic plate deflection is governed by Euler’s beam equation, subject
to free-free boundary conditions. In chapter 4 and 5, impact problems of rigid and elastic
plates and blunt bodies with high horizontal speed are considered. A smooth separation of
the free surface flow from the body is imposed by Kutta’s condition and the Brillouin-Villat
condition. In chapter 6, we account for fluid separation from the body in the free vertical
fall of a rigid plate and a blunt body. In all problems considered in this thesis, the rigid
and elastic plate motions, the fluid flow, and the positions of the turnover regions and the
separation points are coupled.
We found that hydrodynamic forces on an elastic body can be significantly different
from those on a rigid body. In particular, the elasticity of the body can promote cavitation
and ventilation. It is shown that horizontal speed of the body increases the hydrodynamic
forces on the body and the jet energy significantly. For free-fall problems at high horizontal
speed, the body can exit the fluid after entering if the forward speed is large enough. It is
illustrated that the hydrodynamic forces on the body and the motion of the body strongly
depend on the separation model. For the Brillouin-Villat separation criterion, we found that
the position of the separation point is sensitive to the body vibration.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Mathematics
Depositing User: Users 2259 not found.
Date Deposited: 05 Mar 2014 12:26
Last Modified: 05 Mar 2014 12:26

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