Accession Number : ADA115489

Title :   Stern Boundary-Layer Flow on a Three-Dimensional Body of 3:1 Elliptic Cross Section.

Descriptive Note : Final rept.,


Personal Author(s) : Groves,Nancy C ; Belt,Garnell S ; Huang,Thomas T

PDF Url : ADA115489

Report Date : May 1982

Pagination or Media Count : 122

Abstract : A comprehensive set of experimental pressure, velocity, and turbulence data are presented across the stern of a three-dimensional model having 3:1 elliptic transverse cross sections. The axisymmetric displacement body concept is extended to three-dimensions and the pressure and velocity data are compared with the predictions of existing three-dimensional theoretical methods. The surface pressures for the displacement body are found to model, satisfactorily, the measured pressure coefficients in all regions except over the aft 7 percent of body length. In this tail region, the boundary layer is much thicker than the cross section dimensions and the theory overpredicts the measured distributions of the mean velocity. Agreement is particularly poor in the inner region of the tail boundary layer, indicating a need to examine the eddy viscosity model currently used in computing the thick stern boundary layer of three-dimensional models. As was found in the axisymmetric case, the measured values of turbulence intensity, eddy viscosity, and mixing-length parameters in the stern region are much smaller than those of a thin boundary layer. (Author)

Descriptors :   *Boundary layer flow, *Ship sterns, *Ellipses, *Cross sections, *Turbulent boundary layer, Wind tunnel tests, Three dimensional, Wind tunnel models, Ship models, Boundary layer, Thickness, Thinness, Eddy currents, Viscosity, Turbulence, Mathematical models

Subject Categories : Marine Engineering
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE