Wave Viscosity Interaction in Nonlinear Roll Motion
Abstract
The objective of the our research program is to develop rationally- based hydrodynamic models for describing and analyzing viscous flows about ship sections, particularly, in the context of nonlinear roll motion of ships, where viscous damping is known to be important. (1) Grid-generation mathematics for free-surface flows consists of developing the necessary grid-generation mathematics for finite difference methods that would enable the researcher to handle skewed geometries in steep water waves. (2) Hydrodynamic resonance in a closed domains and towing tanks. Some fundamental understanding of the resonant behavior of the fluid in a tank with the presence of floating bodies was indispensable. This is related to the fact that any eventual validation of the theoretical models developed in this research program would require tank testing. The hydrodynamic properties of bodies in a finite-width tank was a subject not well treated. (3) Time harmonic oscillating body in a viscous fluid would allow one to incorporate the effects of viscosity in a framework that can be unified with the formulation of existing, traditional ship-motion theories, thus facilitating eventual practical applications. This research has led to a new theory for calculating added mass and damping of two-dimensional sections in a viscous fluid. Under the appropriate assumptions, we were able to linearize the Navier Stokes Equations to obtain a problem, in which the precise effects of viscosity appear as a frequency-based Reynolds number. (4) High separated flows about blunt bodies examines the behavior of fully nonlinear separated flow based on a grid-independent method. The highlights of some of our recent accomplishment by using a Random Vortex Method (RVM) were given on a graphic sheet.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 27, 1991
- Accession Number
- ADA245756
Entities
Organizations
- University of California, Berkeley