Closure to “Discussion of ‘Investigations of Boundary Layer Transition in an Adverse Pressure Gradient’” (1989, ASME J. Turbomach., 111, p. 374)

1989 ◽  
Vol 111 (4) ◽  
pp. 374-375 ◽  
Author(s):  
J. P. Gostelow ◽  
A. R. Blunden
Keyword(s):  
Boundary Layer ◽  
Pressure Gradient ◽  
Adverse Pressure Gradient ◽  
Boundary Layer Transition ◽  
Layer Transition

scholarly journals Bypass Boundary Layer Transition on Flat Plate by Adverse Pressure Gradient

2019 ◽  
Vol 213 ◽  
pp. 02077
Author(s):  
Vladislav Skála ◽  
Václav Uruba ◽  
Pavel Antoš ◽  
Pavel Jonáš
Keyword(s):  
Boundary Layer ◽  
Wind Tunnel ◽  
Pressure Gradient ◽  
Flat Plate ◽  
Free Stream ◽  
Adverse Pressure Gradient ◽  
Boundary Layer Transition ◽  
Hot Wire ◽  
Layer Transition ◽  
Hot Wire Anemometry

Bypass boundary layer transition in flows on flat plate by adverse pressure gradient was investigated experimentally. It was measuered cases with combination of adverse pressure gradient by different free stream turbulence intenzity. Hot wire anemometry technique was used. Measuerement were made on flat plate in closed wind tunnel. Adverse pressure gradient was set by diffuser in tested section of wind tunnel. Grid turbulence of free stream was controlled by screen. Hot wire anemometry technique was used, intermitency factor was evaluated. Results were compared wih cases with simpliest conditions.

Investigations of Boundary Layer Transition in an Adverse Pressure Gradient

1989 ◽  
Vol 111 (4) ◽  
pp. 366-374 ◽  
Author(s):  
J. P. Gostelow ◽  
A. R. Blunden
Keyword(s):  
Boundary Layer ◽  
Pressure Gradient ◽  
Formation Rate ◽  
Adverse Pressure Gradient ◽  
Boundary Layer Transition ◽  
Strong Increase ◽  
Pressure Gradients ◽  
Turbulent Spot ◽  
Layer Transition ◽  
Spot Formation

Boundary layer transition was measured on a flat plate for four different turbulence levels. A range of adverse pressure gradients was imposed for one of these. The zero pressure gradient results were in agreement with accepted data for transition inception, length, and turbulent spot formation rate. They were also well represented by Narasimha’s universal intermittency distribution. A surprisingly strong similarity was also exhibited by intermittency distributions under adverse pressure gradients. Dimensionless velocity profiles were reasonable for the zero pressure gradient cases but difficulties with skin-friction prediction were experienced under adverse pressure gradient conditions. For this moderate turbulence level the transition inception Reynolds number remained reasonably constant with pressure gradient. Transition lengths, however, were greatly reduced by the imposition of even a weak adverse pressure gradient. This was associated with a strong increase in turbulent spot formation rate.

Influence of Stream Turbulence and Pressure Gradient upon Boundary Layer Transition

1972 ◽  
Vol 14 (2) ◽  
pp. 134-146 ◽  
Author(s):  
D. J. Hall ◽  
J. C. Gibbings
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Pressure Gradient ◽  
Boundary Layer Transition ◽  
Experimental Results ◽  
Prediction Methods ◽  
Layer Transition ◽  
Approximate Nature

In considering boundary layer transition, the available experimental data and prediction methods are reviewed and further experimental results are presented. Some empirical rules are suggested for the separate effects of stream turbulence and of pressure gradient and of both combined. The approximate nature of these rules is described and the causes indicated.

Investigation of the Laminar-Turbulent Transition of Boundary Layers Disturbed by Wakes

1982 ◽  
Author(s):  
H. Pfeil ◽  
R. Herbst ◽  
T. Schröder
Keyword(s):  
Boundary Layer ◽  
Pressure Gradient ◽  
Boundary Layers ◽  
Transition Process ◽  
Boundary Layer Transition ◽  
Layer Transition ◽  
Turbulent Spots ◽  
Turbulent Transition ◽  
Time Space ◽  
Favorable Pressure Gradient

The boundary layer transition under instationary afflux conditions as present in the stages of turbomachines is investigated. A model for the transition process is introduced by means of time-space distributions of the turbulent spots during transition and schematic drawings of the instantaneous boundary layer thicknesses. To confirm this model, measurements of the transition with zero and favorable pressure gradient are performed.

scholarly journals Effects of Periodic Unsteady Wake Flow and Pressure Gradient on Boundary Layer Transition Along the Concave Surface of a Curved Plate

1994 ◽  
Author(s):  
M. T. Schobeiri ◽  
R. E. Radke
Keyword(s):  
Boundary Layer ◽  
Pressure Gradient ◽  
Turbulence Intensity ◽  
Boundary Layer Transition ◽  
Wake Flow ◽  
Concave Surface ◽  
Experimental Investigations ◽  
Ensemble Averaging ◽  
Layer Transition ◽  
Lateral Direction

Boundary layer transition and development on a turbomachinery blade is subjected to highly periodic unsteady turbulent flow, pressure gradient in longitudinal as well as lateral direction, and surface curvature. To study the effects of periodic unsteady wakes on the concave surface of a turbine blade, a curved plate was utilized. On the concave surface of this plate, detailed experimental investigations were carried out under zero and negative pressure gradient. The measurements were performed on an unsteady flow research facility using a rotating cascade of rods positioned upstream of the curved plate. Boundary layer measurements using a hot-wire probe were analyzed by the ensemble-averaging technique. The results presented in the temporal-spatial domain display the transition and further development of the boundary layer, specifically the ensemble-averaged velocity and turbulence intensity. As the results show, the turbulent patches generated by the wakes have different leading and trailing edge velocities and merge with the boundary layer resulting in a strong deformation and generation of a high turbulence intensity core. After the turbulent patch has totally penetrated into the boundary layer, pronounced becalmed regions were formed behind the turbulent patch and were extended far beyond the point they would occur in the corresponding undisturbed steady boundary layer.

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