Flow measurements downstream of a single bleed hole in a subsonic, turbulent boundary layer using a new 5-hole pressure probe

1999 ◽  
Author(s):  
M. Schoenenberger ◽  
I. Greber ◽  
D. Davis
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Pressure Probe ◽  
Flow Measurements ◽  
Hole Pressure

Heat Transfer Effects of a Longitudinal Vortex Embedded in a Turbulent Boundary Layer

1987 ◽  
Vol 109 (1) ◽  
pp. 16-24 ◽  
Author(s):  
P. A. Eibeck ◽  
J. K. Eaton
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Delta Wing ◽  
Stanton Number ◽  
Longitudinal Vortex ◽  
Test Facility ◽  
Pressure Probe ◽  
Transfer Effects ◽  
Heat Transfer Effects

The heat transfer effects of an isolated longitudinal vortex embedded in a turbulent boundary layer were examined experimentally for vortex circulations ranging from Γ/U∞δ99 = 0.12 to 0.86. The test facility consisted of a two-dimensional boundary-layer wind tunnel, with a vortex introduced into the flow by a half-delta wing protruding from the surface. In all cases, the vortex size was of the same order as the boundary-layer thickness. Heat transfer measurements were made using a constant-heat-flux surface with 160 embedded thermocouples to provide high resolution of the surface-temperature distribution. Three-component mean-velocity measurements were made using a four-hole pressure probe. Spanwise profiles of the Stanton number showed local increases as large as 24 percent and decreases of approximately 14 percent. The perturbation to the Stanton number was persistent to the end of the test section, a length of over 100 initial boundary-layer thicknesses. The weakest vortices examined showed smaller heat transfer effects, but the Stanton number profiles were nearly identical for the three cases with circulation greater than Γ/U∞δ99 = 0.53 cm. The local increase in the Stanton number is attributed to a thinning of the boundary layer on the downwash side of the vortex.

scholarly journals An experiment on the adiabatic compressible turbulent boundary layer in adverse and favourable pressure gradients

1972 ◽  
Vol 51 (4) ◽  
pp. 657-672 ◽  
Author(s):  
J. E. Lewis ◽  
R. L. Gran ◽  
T. Kubota
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Pressure Gradients ◽  
Mean Flow ◽  
Adiabatic Wall ◽  
Flow Measurements ◽  
Low Speed ◽  
Velocity Transformation ◽  
Tunnel Model ◽  
Gradient Parameter

A wind-tunnel model was developed to study the two-dimensional turbulent boundary layer in adverse and favourable pressure gradients with out the effects of streamwise surface curvature. Experiments were performed at Mach 4 with an adiabatic wall, and mean flow measurements within the boundary layer were obtained. The data, when viewed in the velocity transformation suggested by Van Driest, show good general agreement with the composite boundary-layer profile developed for the low-speed turbulent boundary layer. Moreover, the pressure gradient parameter suggested by Alber & Coats was found to correlate the data with low-speed results.

On turbulent boundary layers in oscillatory flow

1977 ◽  
Vol 353 (1672) ◽  
pp. 121-144 ◽  
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Boundary Layers ◽  
Travelling Wave ◽  
Convection Velocity ◽  
Mean Flow ◽  
Mean Velocity ◽  
Flow Measurements ◽  
Freestream Velocity ◽  
The Mean

An experimental investigation has been made of turbulent boundary layer response to harmonic oscillations associated with a travelling wave imposed on an otherwise constant freestream velocity and convected in the freestream direction. The tests covered oscillation frequencies of 4-12 Hz for freestream amplitudes of up to 11% of the mean velocity. Additional steady flow measurements were used to infer the quasi-steady response to freestream oscillations. The results show a welcome insensitivity of the mean flow and turbulent intensity distributions to the freestream oscillations tested. An approximate analysis based on these results has been developed. It is probably of limited validity but it does provide a useful guide to the physical processes involved. The effects on boundary layer response of varying the travelling wave convection velocity and frequency of oscillation are illustrated by the analysis and show a behaviour broadly similar to that of laminar boundary layers. The travelling wave convection velocity exhibits a dominant influence on the turbulent boundary layer response to freestream oscillations.

A Four Hole Pressure Probe for Fluid Flow Measurements in Three Dimensions

1981 ◽  
Vol 103 (4) ◽  
pp. 590-594 ◽  
Author(s):  
I. C. Shepherd
Keyword(s):  
Fluid Flow ◽  
Three Dimensions ◽  
Central Hole ◽  
Pressure Probe ◽  
Redundant Information ◽  
Mean Flow ◽  
Flow Measurements ◽  
Hole Pressure ◽  
Dependent Flow

A pressure probe which facilitates measurement of mean flow quantities in three dimensions simultaneously is described. Its main feature is a tip shaped like the frustrum of a pyramid, with three-side holes equispaced around a central hole. Flow quantities are related to the hole pressures by calibration, so that the tedious procedure of nulling or pressure balancing can be avoided. The advantages of this configuration over five-hole probes are that a simpler probe with a smaller head results, fewer pressures need to be recorded and because no redundant information is collected, determination of the dependent flow quantities is simpler and unambiguous.

The Turbulent Boundary Layer on an Axial Compressor Blade

1982 ◽  
Author(s):  
G. J. Walker
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Turbulent Boundary Layer ◽  
Convex Surface ◽  
Axial Compressor ◽  
Reynolds Numbers ◽  
Positive Pressure ◽  
Mean Flow ◽  
Flow Measurements ◽  
Moderate Reynolds Number

Time-mean flow measurements of turbulent boundary layer development on the convex surface of an outlet stator blade in a single-stage axial compressor are presented. There is no evidence of logarithmic wall similarity at blade chord Reynolds numbers from 3 × 104 to 2 × 105, and its absence appears due to the combined effects of low Reynolds number, large positive pressure gradient and rapidly changing boundary conditions. Conventional skin friction laws compare very poorly with experiment. The performance of local equilibrium and entrainment-type calculation methods is examined and serious errors are found to develop at blade Reynolds numbers below 105. The best results are obtained from a lag-entrainment method of Green, Weeks and Brooman, which can be recommended for predicting axial turbomachine blade boundary layers at moderate Reynolds number.

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