Accession Number : ADA188356

Title :   Effects of Waves on the Boundary Layer of a Surface-Piercing Flat Plate: Experiment and Theory.

Descriptive Note : Technical rept.,

Corporate Author : IOWA INST OF HYDRAULIC RESEARCH IOWA CITY

Personal Author(s) : Stern, F ; Hwang, W S ; Jaw, S Y

PDF Url : ADA188356

Report Date : Sep 1987

Pagination or Media Count : 67

Abstract : Results are presented from a towing tank experiment conducted in order to document the effects of waves on the boundary layer of a surface piercing body. A unique, simple model geometry is utilized which makes it possible to identify and isolate the most important features of the wave induced effects. Measurements were made of wave profiles as well as detailed boundary layer velocity profiles for three wave steepness conditions: zero, medium, and large. The effects of the waves for both the medium and large steepness conditions are shown to be significant. In particular, the variations of the external flow piezometric pressure gradients cause acceleration and deceleration phases of the streamwise velocity component and alternating direction of the cross flow which result in large oscillations of the displacement thickness and wall shear stress as compared to the zero steepness condition. The magnitude of these trends increases with increasing wave steepness. Wave induced separation, which is present under certain conditions in the experiments, and other relevant phenomena are discussed. The measurements are compared and close agreement is demonstrated with results from first-order boundary layer calculations with a symmetry condition approximation for the free-surface boundary conditions.

Descriptors :   *BOW SHOCK, *WATER WAVES, *BOUNDARY LAYER FLOW, *THREE DIMENSIONAL FLOW, ACCELERATION, BOUNDARIES, BOUNDARY LAYER, COMPUTATIONS, CROSS FLOW, DECELERATION, DISPLACEMENT, DOCUMENTS, DOWNSTREAM FLOW, FLAT PLATE MODELS, FLOW, MODEL BASINS, OSCILLATION, PATTERNS, PHASE, PRESSURE GRADIENTS, PROFILES, SEPARATION, SHEAR STRESSES, SURFACES, SYMMETRY, THICKNESS, VELOCITY

Subject Categories : Physical and Dynamic Oceanography
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE