We study inertial motions of the coupled system, \({\mathscr{S}}\), constituted by a rigid body containing a cavity entirely filled with a viscous liquid. We show that for arbitrary initial data having only finite kinetic energy, every corresponding weak solution (a la Leray–Hopf) converges, as time goes to infinity, to a uniform rotation, unless two central moments of inertia of \({\mathscr{S}}\) coincide and are strictly greater than the third one. This corroborates a famous “conjecture” of N.Ye. Zhukovskii in several physically relevant cases. Moreover, we show that, in a known range of initial data, this rotation may only occur along the central axis of inertia of \({\mathscr{S}}\) with the larger moment of inertia. We also provide necessary and sufficient conditions for the rigorous nonlinear stability of permanent rotations, which improve and/or generalize results previously given by other authors under different types of approximation. Finally, we present results obtained by a targeted numerical simulation that, on the one hand, complement the analytical findings, whereas, on the other hand, point out new features that the analysis is yet not able to catch, and, as such, lay the foundation for interesting and challenging future investigation.

This book presents some of the papers presented at the XIXth Conference of the Technical Committee 7 of the International Federation of Information Processing (IFIP). It was held in Cambridge, England, during the period 12-16 July, 1999. This conference is the most important of the specialized IFIP’s congresses in the theme. Some submitted papers are published in the book. It is a small sample of the delivered talks which was determined through an exigent reviewing process.

To preserve a number of physically relevant invariants is a major concern when considering long time integration of the Vlasov equation. In the present work we consider the semi-Lagrangian discontinuous Galerkin method for the Vlasov-Poisson system. We discuss the performance of this method and compare it to cubic spline interpolation, where appropriate. In addition, numerical simulations for the two-stream instability are shown.

I. Mathematical Foundation of the Stokes Problem.- 1. Generalities on Some Elliptic Boundary Value Problems.- 1.1. Basic Concepts on Sobolev Spaces.- 1.2. Abstract Elliptic Theory.- 1.3. Example 1: Dirichlet's Problem for the Laplace Operator.- 1.4. Example 2: Neumann's Problem for the Laplace Operator.- 1.5. Example 3: Dirichlet's Problem for the Biharmonic Operator.- 2. Function Spaces for the Stokes Problem.- 2.1. Preliminary Results.- 2.2. Some Properties of Spaces Related to the Divergence ...

#2Václav Mácha(CAS: Academy of Sciences of the Czech Republic)H-Index: 8

Last. Šárka Nečasová(CAS: Academy of Sciences of the Czech Republic)H-Index: 2

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We prove the existence of a weak solution to the equations describing the inertial motions of a coupled system constituted by a rigid body containing a viscous compressible fluid. We then provide a weak-strong uniqueness result that allows us to completely characterize, under certain physical assumptions, the asymptotic behavior in time of the weak solution corresponding to smooth data of restricted "size" and show that it tends to a uniquely determined steady-state.

#2Jan Prüss(MLU: Martin Luther University of Halle-Wittenberg)H-Index: 47

Last. Gieri Simonett(Vandy: Vanderbilt University)H-Index: 28

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We consider the inertial motion of a rigid body with an interior cavity that is completely filled with a viscous incompressible fluid. The equilibria of the system are characterized and their stability properties are analyzed. It is shown that equilibria associated with the largest moment of inertia are normally stable, while all other equilibria are normally hyperbolic. We show that every Leray–Hopf weak solution converges to an equilibrium at an exponential rate. In addition, we determine the ...

We study the motion of the system, ${\mathcal S} , constituted by a rigid body, {\mathcal{B}} , containing in its interior a viscous compressible fluid, and moving in absence of external forces. Our main objective is to characterize the long time behavior of the coupled system body-fluid. Under suitable assumptions on the “mass distribution” of {\mathcal{S}} , and for a sufficiently “small” Mach number and initial data, we show that every corresponding motion (in a suitable regularity...

Last. Gieri Simonett(Vandy: Vanderbilt University)H-Index: 28

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We consider the inertial motion of a rigid body with an interior cavity that is completely filled with a viscous incompressible fluid. The equilibria of the system are characterized and their stability properties are analyzed. It is shown that equilibria associated with the largest moment of inertia are normally stable, while all other equilibria are normally hyperbolic. We show that every Leray-Hopf weak solution converges to an equilibrium at an exponential rate. In addition, we determine the ...

A rigid body, with an interior cavity entirely filled with a Navier-Stokes liquid, moves in absence of external torques relative to the center of mass of the coupled system body-liquid (inertial motions). The only steady-state motions allowed are then those where the system, as a whole rigid body, rotates uniformly around one of the central axes of inertia (permanent rotations). Objective of this article is twofold. On the one hand, we provide sufficient conditions for the asymptotic, exponentia...

Last. Paolo Zunino(University of Pittsburgh)H-Index: 28

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We study inertial motions of the coupled system, \({\mathscr{S}}\), constituted by a rigid body containing a cavity entirely filled with a viscous liquid. We show that for arbitrary initial data having only finite kinetic energy, every corresponding weak solution (a la Leray–Hopf) converges, as time goes to infinity, to a uniform rotation, unless two central moments of inertia of \({\mathscr{S}}\) coincide and are strictly greater than the third one. This corroborates a famous “conjecture” of N....

In this paper we investigate the existence of time-periodic motions of a system constituted by a rigid body with an interior cavity completely filled with a viscous liquid, and subject to a time-periodic external torque acting on the rigid body. We then show that the system of equations governing the motion of the coupled system liquid-filled rigid body, has at least one corresponding time-periodic weak solution. Furthermore if the size of the torque is below a certain constant, the weak solutio...

Last. George Weiss(TAU: Tel Aviv University)H-Index: 43

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Abstract We consider the mathematical model of a rigid ball moving in a viscous incompressible fluid occupying a bounded domain Ω, with an external force acting on the ball. We investigate in particular the case when the external force is what would be produced by a spring and a damper connecting the center of the ball h to a fixed point h 1 ∈ Ω . If the initial fluid velocity is sufficiently small, and the initial h is sufficiently close to h 1 , then we prove the existence and uniqueness of gl...