scholarly journals Compressible turbulent boundary layers with heat transfer and pressure gradient in flow direction

1959 ◽  
Vol 63B (1) ◽  
pp. 53 ◽  
Author(s):  
Alfred Walz
Keyword(s):  
Heat Transfer ◽  
Pressure Gradient ◽  
Boundary Layers ◽  
Flow Direction ◽  
Turbulent Boundary Layers

Prediction of Heat Transfer in Turbulent, Transpired Boundary Layers

1999 ◽  
Vol 121 (1) ◽  
pp. 186-190 ◽  
Author(s):  
J. Sucec
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Pressure Gradient ◽  
Boundary Layers ◽  
Energy Equation ◽  
Integral Form ◽  
Turbulent Boundary Layers ◽  
Equation Solving ◽  
Turbulent Boundary Layer Flow ◽  
Layer Flow

Considered here is turbulent boundary layer flow with injection or suction and pressure gradient along the surface. The velocity and thermal inner laws for transpired turbulent boundary layers are represented by simple power law forms which are then used to solve the integral form of the thermal energy equation. Solving this equation leads to the variation of Stanton number with position, x, along the surface. Predicted Stanton numbers are compared with experimental data for a number of different cases. These include both blowing and suction with constant blowing fractions, F, in zero and non-zero pressure gradient and more complicated situations in which the blowing fraction, F, varies with position or where F or the surface temperature have step changes in value.

scholarly journals Skin Friction and the Inner Flow in Pressure Gradient Turbulent Boundary Layers

2006 ◽  
Author(s):  
Katherine Newhall ◽  
Brian Brzek ◽  
Raul Bayoan Cal ◽  
Gunnar Johansson ◽  
Luciano Castillo
Keyword(s):  
Pressure Gradient ◽  
Skin Friction ◽  
Boundary Layers ◽  
Turbulent Boundary Layers

Effects of Embedded Vortices on Film-Cooled Turbulent Boundary Layers

1989 ◽  
Vol 111 (1) ◽  
pp. 71-77 ◽  
Author(s):  
P. M. Ligrani ◽  
A. Ortiz ◽  
S. L. Joseph ◽  
D. L. Evans
Keyword(s):  
Heat Transfer ◽  
Boundary Layers ◽  
Film Cooling ◽  
Free Stream ◽  
Flow Behavior ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Turbulent Boundary Layers ◽  
Stream Velocity ◽  
Longitudinal Vortices

Heat transfer effects of longitudinal vortices embedded within film-cooled turbulent boundary layers on a flat plate were examined for free-stream velocities of 10 m/s and 15 m/s. A single row of film-cooling holes was employed with blowing ratios ranging from 0.47 to 0.98. Moderate-strength vortices were used with circulating-to-free stream velocity ratios of −0.95 to −1.10 cm. Spatially resolved heat transfer measurements from a constant heat flux surface show that film coolant is greatly disturbed and that local Stanton numbers are altered significantly by embedded longitudinal vortices. Near the downwash side of the vortex, heat transfer is augmented, vortex effects dominate flow behavior, and the protection from film cooling is minimized. Near the upwash side of the vortex, coolant is pushed to the side of the vortex, locally increasing the protection provided by film cooling. In addition, local heat transfer distributions change significantly as the spanwise location of the vortex is changed relative to film-cooling hole locations.

Measurements in adverse-pressure-gradient turbulent boundary layers with a step change in surface roughness

1975 ◽  
Vol 70 (3) ◽  
pp. 573-593 ◽  
Author(s):  
W. H. Schofield
Keyword(s):  
Surface Roughness ◽  
Pressure Gradient ◽  
Boundary Layers ◽  
Leading Edge ◽  
Adverse Pressure Gradient ◽  
Turbulent Boundary Layers ◽  
Step Change ◽  
Internal Layer ◽  
Mean Velocity ◽  
Law Of The Wall

The response of turbulent boundary layers to sudden changes in surface roughness under adverse-pressure-gradient conditions has been studied experimentally. The roughness used was in the ‘d’ type array of Perry, Schofield & Joubert (1969). Two cases of a rough-to-smooth change in surface roughness were considered in the same arbitrary adverse pressure gradient. The two cases differed in the distance of the surface discontinuity from the leading edge and gave two sets of flow conditions for the establishment and growth of the internal layer which develops downstream from a change in surface roughness. These conditions were in turn different from those in the zero-pressure-gradient experiments of Antonia & Luxton. The results suggest that the growth of the new internal layer depends solely on the new conditions at the wall and scales with the local roughness length of that wall. Mean velocity profiles in the region after the step change in roughness were accurately described by Coles’ law of the wall-law of the wake combination, which contrasts with the zero-pressure-gradient results of Antonia & Luxton. The skin-friction coefficient after the step change in roughness did not overshoot the equilibrium distribution but made a slow adjustment downstream of the step. Comparisons of mean profiles indicate that similar defect profile shapes are produced in layers with arbitrary adverse pressure gradients at positions where the values of Clauser's equilibrium parameter β (= δ*τ−10dp/dx) are similar, provided that the pressure-gradient history and local values of the pressure gradient are also similar.

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