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A database for the complex turbulent flow of a confined double annular burner in cold conditions is presented here. In the region close to the exit of the annular nozzles LDV measurements at 5515 grid points in the meridional plane were conducted. At each measurement position, validated data for 3000–16,000 particles were recorded, and the mean axial and radial velocities, axial and radial turbulence intensity and Reynolds stresses were computed. The resulting mean flow field is axisymmetric within an uncertainty of 2 percent. The contour plots of turbulent quantities on the fine grid, as well as the streamlines based on the mean flow field, are presented for the flow.

The variation of intermittency factors in the transition region of a C4 leading edge flat plate is measured at three incidence angles in a low-turbulence free stream. During the determination of intermittency factor, the threshold value of the detector function and the validity of conditional averaging are verified by a method based on the direct application of PDF of the hot-wire output. As the angle of incidence is increased, the transition progressively moves through all the three modes on the suction surface: at zero incidence the bypass transition, at 2 deg incidence the natural transition, and at 4 deg incidence the separated-flow transition occur, respectively. All three modes of transition exhibited the chordwise intermittency factor variation in accordance with Narasimha’s universal intermittency distribution; thus, the method based on spot production rate is applicable to all the three modes of transition. In the transition zone of the attached boundary layers, the conditionally averaged interturbulent profiles are fuller than the Blasius profile, while the conditionally averaged turbulent profiles follow a logarithmic profile with a variable additive parameter.

The three-dimensional flow in the blade end wall corner region was investigated. The techniques used in the investigation included flow visualization, static and total pressure measurements with conventional probes, and mean velocity profile measurements with a single sensor inclined hot-wire probe. Six critical axial stations along the blade chord were chosen for detailed measurements based on the flow visualization resdults. A large number of data points were obtained very close to the corner walls at each axial location including all the components of the mean velocity. Based on the measurements, three vortices were identified. A horseshoe vortex started near the leading edge. A comer eddy was formed between the horseshow vortex and the corner. Another vortex was formed at the rear portion of the corner due to the secondary flow of the second kind. The relative size and the rate of spread of the vortices in the streamwise direction are discussed. Z M Height above the flat plate at which maximum occurs. Z m Height above the flat plate at which minimum occurs, δ Distance at which U/Uoo is 0.995 (boundary layer thickness) θ Momentum thickness Superscript RMS value of the fluctuating quantity Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 7/31/15 4:21 PM

The flow around a circular leading edge airfoil is investigated in an incompressible, low turbulence freestream. Hot-wire measurements are performed through the separation bubble, the reattachment and the recovery region till development of the fully turbulent boundary layer. The results of the experiments in the range of Reynolds numbers 1.7×103 to 11.8×103 are analysed and presented in this paper. A separation bubble is present near the leading edge at all Reynolds numbers. At the lowest Reynolds number investigated, the transition is preceded by strong low frequency oscillations. The correlation given by Mayle for prediction of transition of short separation bubbles is successful at the lower Reynolds number cases. The length of the separation bubble reduces considerably with increasing Reynolds number in the range investigated. The turbulence in the reattached flow persists even when the Reynolds number based on momentum thickness of the reattached boundary layer is small. The recovery length of the reattached layer is relatively short and the mean velocity profile follows logarithmic law within a short distance downstream of the reattachment point and the friction coefficient conforms to Prandtl-Schlichting skin-friction formula for a smooth flat plate at zero incidence.