Tangential and normal velocity profiles of the boundary layer surrounding live swimming fish were determined by digital particle tracking velocimetry, DPTV. Two species were examined: the scup Stenotomus chrysops, a carangiform swimmer, and the smooth dogfish Mustelus canis, an anguilliform swimmer. Measurements were taken at several locations over the surfaces of the fish and throughout comple...

A laminar boundary layer separates in a region of adverse pressure gradient on a flat plate, undergoes transition, and finally the turbulent boundary layer reattaches. Laminar-turbulent transition within this laminar separation bubble (LSB) is investigated by means of measurements with a Laser-Doppler-Anemometer (LDA), flow visualization in water and direct numerical simulation (DNS). The role ...

We formulate the mass transfer problem for a passive additive in a turbulent boundary layer based on the recently proposed model of the turbulent boundary layer at very large Reynolds numbers. The solutions of three basic problems are obtained. These solutions are self-similar asymptotics describing the mass exchange at its initial stages. The solutions obtained can be used for the construction...

A new dynamical subgrid model for turbulent flow is used to derive the structure of the heat and momentum fluxes, mean wind and temperature profiles, and temperature and velocity variances, as a function of the Richardson number, in the surface layer of the planetary boundary layer. Analytical solutions are obtained for stationary, homogeneous surface layers and are compared with field observat...

Bottom boundary layer effects on the linear wave propagation over mild slope bottoms are analyzed. A modifiedWKB approximation is presented including boundary layer effects. Within the boundary layer, two cases are considered: laminar (constant viscosity) and turbulent. Boundary layer effects are introduced by coupling the velocity inside the boundary layer to the irrotational velocity in the c...

Swifts are aerodynamically sophisticated birds with a small arm and large hand wing that provides them with exquisite control over their glide performance. However, their hand wings have a seemingly unsophisticated surface roughness that is poised to disturb flow. This roughness of about 2% chord length is formed by the valleys and ridges of overlapping primary feathers with thick protruding ra...

Direct numerical simulations were performed to investigate the physics of a spatially-developing turbulent boundary layer flow subjected to spanwise oscillating electromagnetic force. The electromagnetic force beneath the flat plate was locally given with a finite length. A fully implicit fractional step method was employed to simulate the flow. The mean flow properties and the Reynolds stresse...

in this research, shock wave motion, shock/boundary layer interaction, and flow separation in a transonic flow over a naca0012 airfoil were investigated experimentally. thirteen kulite sensors were utilized for measurement of pressure fluctuations over the airfoil. experiments were performed for angles of attack between -4 to 4 degrees and flow mach numbers of m= 0.39 to 0.82. the kulite sensor...

Scaling of the interface that demarcates a turbulent boundary layer from the non-turbulent free stream is sought using theoretical reasoning and experimental evidence in a zero-pressure-gradient boundary layer. The data-analysis, utilising particle image velocimetry (PIV) measurements at four different Reynolds numbers (δuτ/ν = 1200–14 500), indicates the presence of a viscosity dominated inter...

This communication presents the results and conclusions of an experimental study of the near-separation region of a single-stream shear layer. The momentum thickness at separation (x=0) was θ0 = 9.6mm, with Reynolds number Reθ =4650. Boundary layer separation was caused by a sharp 90◦ edge. Detailed singleand multipoint measurements of the velocity field were acquired at the streamwise location...