Non-Equilibrium and Equilibrium Boundary Layers without Pressure Gradient

2008 ◽  
pp. 197-202
Author(s):  
Takatsugu Kameda ◽  
Shinsuke Mochizuki ◽  
Hideo Osaka
Keyword(s):  
Pressure Gradient ◽  
Boundary Layers ◽  
Non Equilibrium

scholarly journals Mean flow structure of non-equilibrium boundary layers with adverse pressure gradient

Sadhana ◽  
2014 ◽  
Vol 39 (5) ◽  
pp. 1211-1226
Author(s):  
B C MANDAL ◽  
H P MAZUMDAR ◽  
S S DUTTA
Keyword(s):  
Pressure Gradient ◽  
Boundary Layers ◽  
Flow Structure ◽  
Adverse Pressure Gradient ◽  
Mean Flow ◽  
Non Equilibrium

scholarly journals The Second Mode in High-enthalpy Boundary Layers in Chemical Non-equilibrium

2015 ◽  
Vol 14 ◽  
pp. 45-47
Author(s):  
Jill Klentzman ◽  
Anatoli Tumin
Keyword(s):  
Boundary Layers ◽  
High Enthalpy ◽  
Second Mode ◽  
Non Equilibrium

Direct total skin-friction measurement of a flat plate in zero-pressure-gradient boundary layers

2009 ◽  
Vol 41 (2) ◽  
pp. 021406 ◽  
Author(s):  
Kiyoto Mori ◽  
Hiroki Imanishi ◽  
Yoshiyuki Tsuji ◽  
Tomohiro Hattori ◽  
Masaharu Matsubara ◽  
...  
Keyword(s):  
Pressure Gradient ◽  
Flat Plate ◽  
Skin Friction ◽  
Boundary Layers ◽  
Friction Measurement

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

Modeling of External Pressure Gradient Influence on the Stability of Disturbances in the Boundary Layers of Compressed Gas

2013 ◽  
Vol 8 (4) ◽  
pp. 64-75
Author(s):  
Sergey Gaponov ◽  
Natalya Terekhova
Keyword(s):  
Mach Number ◽  
Pressure Gradient ◽  
Boundary Layers ◽  
Leading Edge ◽  
External Pressure ◽  
Transition To Turbulence ◽  
Compressed Gas ◽  
High Mach ◽  
The Stability ◽  
Very High

This work continues the research on modeling of passive methods of management of flow regimes in the boundary layers of compressed gas. Authors consider the influence of pressure gradient on the evolution of perturbations of different nature. For low Mach number M = 2 increase in pressure contributes to an earlier transition of laminar to turbulent flow, and, on the contrary, drop in the pressure leads to a prolongation of the transition to turbulence. For high Mach number M = 5.35 found that the acoustic disturbances exhibit a very high dependence on the sign and magnitude of the external gradient, with a favorable gradient of the critical Reynolds number becomes smaller than the vortex disturbances, and at worst – boundary layer is destabilized directly on the leading edge

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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