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Updated: Oct 3, 2025

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Impacts of Free-falling Spheres on a Deep Liquid Pool with Altered Fluid and Impactor Surface Conditions
Published on: February 17, 2019
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Mechanics of floating bodies
Robert Beig1, Bernd G Schmidt2
1Gravitational Physics, Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria.
Summary
This study analyzes the stability of rigid bodies floating in fluids. Equilibria are proven stable if they meet a condition similar to the metacentric criterion.
Area of Science:
- Fluid dynamics
- Solid mechanics
- Hydrostatics
Background:
- Archimedes' principle and buoyancy are foundational to fluid mechanics.
- Standard equilibrium theories often assume simplified body geometries.
- Understanding the stability of floating bodies is crucial in naval architecture and engineering.
Purpose of the Study:
- To develop and analyze a mechanical system for rigid bodies of constant density in a calm incompressible fluid.
- To investigate the statics and dynamics of floating convex bodies.
- To establish conditions for the stability of floating rigid bodies.
Main Methods:
- Formulation of a mechanical system for rigid body dynamics and statics.
- Analysis of equilibria for convex bodies, avoiding assumptions beyond convexity.
- Application of Lyapunov stability theory.
Main Results:
- The study introduces a mechanical system for floating rigid bodies.
- It demonstrates that convex bodies can be analyzed without assuming higher regularity.
- A key finding is the Lyapunov stability of equilibria meeting a metacentric criterion-equivalent condition.
Conclusions:
- The developed mechanical system provides a rigorous framework for studying floating bodies.
- The results confirm the stability of equilibria under specific geometric and physical conditions.
- This work extends classical hydrostatics with modern stability analysis techniques.
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