SOLID FREE-SURFACE JUNCTURE BOUNDARY-LAYER AND WAKE/

The Reynolds-averaged flow for a solid/free-surface juncture boundary layer and wake is documented. The three mean-velocity components and f ive of the Reynolds stresses are measured for a surface-piercing flat plate in a towing tank using a laser-Doppler velocimeter system for bo th boundary-layer and wake planes in regions close to the free surface . The experimental method is described, including the foil-plate model , laser-Doppler velocimeter system, conditions, and uncertainty analys is. The underlying flow data is in excellent agreement with benchmark data. Inner (near the plate and wake centerplane and below the free su rface) and outer (near the free surface) regions of high streamwise vo rticity of opposite sign are observed, which transport, respectively, high mean velocity and low turbulence from the outer to the inner and low mean velocity and high turbulence from the inner to the outer port ions of the boundary layer and wake. For the wake, the inner region of vorticity is relatively weak. The physical mechanism for the streamwi se vorticity is analyzed with regard to the Reynolds-averaged streamwi se vorticity equation. The anisotropy of the crossplane normal Reynold s stresses closely correlates with the vorticity and, additionally, in dicates similarity, i.e., its nature is such that it only depends on t he proximity to the plate and free surface boundaries or wake centerpl ane symmetry plane. Free-surface effects on the Reynolds stresses are analyzed with regard to the behavior close to the free surface of the turbulent kinetic energy and the normal components of the anisotropy t ensor and the anisotropy invariants. Close to the free surface, the tu rbulent kinetic energy is nearly constant and increases for the inner and outer portions, respectively, of the boundary layer and wake and t he normal components of the anisotropy tensor and the anisotropy invar iants roughly correspond to the limiting values for two-component turb ulence. The similarities and differences between the present results a nd analysis with those from related studies are discussed. The data an d analysis should have practical application with regard to the develo pment of turbulence models for computational fluid dynamics methods fo r the Reynolds-averaged Navier-Stokes equations.