Accession Number:

ADA158053

Title:

Effects of Waves on the Boundary Layer of a Surface-Piercing Body

Descriptive Note:

Technical rept. Nov 1983-May 1985

Corporate Author:

IOWA INST OF HYDRAULIC RESEARCH IOWA CITY

Personal Author(s):

Report Date:

1985-05-01

Pagination or Media Count:

69.0

Abstract:

The boundary-value problem associated with the boundary-layer development on a surface-piercing body is formulated in a rigorous manner in which proper consideration is given both to the kinematic and dynamic boundary conditions and to the deformation of the potential-flow free surface within the boundary layer. Simplifications that are appropriate for small amplitude waves are then investigated. The flow flow field in the neighborhood of the body-boundary-layerfree-surface juncture is divided into five regions and order-of-magnitude estimated for each region are provided. Of particular interest is the bodyfree-surface boundary layer in the region very close to the free surface in which the free-surface boundary conditions have a significant influence. In this region, it is shown that, for laminar flow, the parameter Ake where Ak is the wave-steepness parameter and e deltaL is the nondimensional boundary-layer thickness is an important parameter for characterizing the flow. Different solution regimes are identified depending on the magnitude of Ake. In particular, for Ake sufficiently large such that the free-surface boundary conditions have a significant influence a consistent formulation requires the solution of the partially-parabolic Navier-Stokes equations. For turbulent flow, these conclusions cannot be reached with the same degree of certainty due to the present uncertainties in turbulence modelling, especially when a free surface is present. Numerical results are provided for the idealized geometry of a combination Stokes-waveflat-plate. Keywords Waveboundary layer interaction 3-D boundary layer Ship boundary layer.

Subject Categories:

  • Numerical Mathematics
  • Marine Engineering
  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE