Effects of waves on the boundary layer of a surfacepiercing body
Abstract
The boundaryvalue problem associated with the boundarylayer development on a surfacepiercing 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 potentialflow free surface within the boundary layer. Simplifications that are appropriate for small amplitude waves are then investigated. The flow field in the neighborhood of the bodyboundarylayer/freesurface juncture is divided into five regions and orderofmagnitude estimated for each region are provided. Of particular interest is the body freesurface boundary layer in the region very close to the free surface in which the freesurface boundary conditions have a significant influence. In this region, it is shown that, for laminar flow, the parameter Ak/e (where Ak is the wavesteepness parameter and e = delta/L is the nondimensional boundarylayer thickness) is an important parameter for characterizing the flow. Different solution regimes are identified depending on the magnitude of Ak/e. In particular, for Ak/e the magnitude is sufficiently large such that the freesurface boundary conditions have a significant influence. A consistent formulation requires the solution of the partiallyparabolic NavierStokes 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 Stokeswave/flatplate.
 Publication:

Iowa University Progress Report
 Pub Date:
 May 1985
 Bibcode:
 1985iowa.reptR....S
 Keywords:

 Boundary Layers;
 Boundary Value Problems;
 Deformation;
 Kinematics;
 Laminar Flow;
 NavierStokes Equation;
 Penetration;
 Ships;
 Surface Layers;
 Three Dimensional Boundary Layer;
 Amplitudes;
 Boundary Conditions;
 Consistency;
 Dynamic Models;
 Flow Distribution;
 Interfaces;
 Potential Flow;
 Thickness;
 Turbulence;
 Water Waves;
 Fluid Mechanics and Heat Transfer