Effect of Isolated Roughness Elements on Boundary-Layer Transition for Shuttle Orbiter

1997 ◽  
Vol 34 (4) ◽  
pp. 426-436 ◽  
Author(s):  
John J. Bertin ◽  
Kenneth F. Stetson ◽  
Stanley A. Bouslog ◽  
Jose M. Caram
Keyword(s):  
Boundary Layer ◽  
Boundary Layer Transition ◽  
Layer Transition ◽  
Roughness Elements

Infrared thermography of hypersonic boundary layer transition induced by isolated roughness elements

2021 ◽  
Author(s):  
Shicheng Liu ◽  
Meng Wang ◽  
Hao Dong ◽  
Tianyu Xia ◽  
Lin Chen ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Infrared Thermography ◽  
Roughness Element ◽  
Transition Process ◽  
Boundary Layer Transition ◽  
Hypersonic Boundary Layer ◽  
Layer Transition ◽  
Leading Role ◽  
Roughness Elements ◽  
Element Shape

Roughness element induced hypersonic boundary layer transition on a flat plate is investigated using infrared thermography at Ma = 5 and 6 flow condition. Surface Stanton number is acquired to analyze the effect of roughness element shape and height on the transition process. The correlation between the vortex structure induced by roughness element and the wall heat streaks is established. The results indicate that higher roughness element would induce stronger streamwise heat flux streaks, lead to transition advance in streamwise centerline and increase the width of spanwise wake. Moreover, for low roughness element, the effect of the shape is not obvious, and the height plays a leading role in the transition; for tall roughness element, the effect on accelerating transition for the diamond roughness element is the best, the square is the worst, and the shape plays a leading role in the transition.

Parameterization of Boundary-Layer Transition Induced by Isolated Roughness Elements

AIAA Journal ◽  
2014 ◽  
Vol 52 (10) ◽  
pp. 2261-2269 ◽  
Author(s):  
Matteo Bernardini ◽  
Sergio Pirozzoli ◽  
Paolo Orlandi ◽  
Sanjiva K. Lele
Keyword(s):  
Boundary Layer ◽  
Boundary Layer Transition ◽  
Layer Transition ◽  
Roughness Elements

The Effects of a Trip Wire and Unsteadiness on a High-Speed Highly Loaded Low-Pressure Turbine Blade

2004 ◽  
Vol 127 (4) ◽  
pp. 747-754 ◽  
Author(s):  
M. Vera ◽  
H. P. Hodson ◽  
R. Vazquez
Keyword(s):  
Boundary Layer ◽  
High Speed ◽  
Low Pressure ◽  
Boundary Layer Transition ◽  
Layer Transition ◽  
Low Pressure Turbine ◽  
Roughness Elements ◽  
Unsteady Inflow ◽  
Mach Numbers ◽  
Inflow Conditions

This paper presents the effect of a single spanwise two-dimensional wire upon the downstream position of boundary layer transition under steady and unsteady inflow conditions. The study is carried out on a high turning, high-speed, low pressure turbine (LPT) profile designed to take account of the unsteady flow conditions. The experiments were carried out in a transonic cascade wind tunnel to which a rotating bar system had been added. The range of Reynolds and Mach numbers studied includes realistic LPT engine conditions and extends up to the transonic regime. Losses are measured to quantify the influence of the roughness with and without wake passing. Time resolved measurements such as hot wire boundary layer surveys and surface unsteady pressure are used to explain the state of the boundary layer. The results suggest that the effect of roughness on boundary layer transition is a stability governed phenomena, even at high Mach numbers. The combination of the effect of the roughness elements with the inviscid Kelvin–Helmholtz instability responsible for the rolling up of the separated shear layer (Stieger, R. D., 2002, Ph.D. thesis, Cambridge University) is also examined. Wake traverses using pneumatic probes downstream of the cascade reveal that the use of roughness elements reduces the profile losses up to exit Mach numbers of 0.8. This occurs with both steady and unsteady inflow conditions.

Influence of distributed roughness elements on boundary layer transition for NACA0012 airfoil

2018 ◽  
Vol 32 (29) ◽  
pp. 1850349 ◽  
Author(s):  
Hao Dong ◽  
Shicheng Liu ◽  
Xi Geng ◽  
Kun Zhang ◽  
Keming Cheng
Keyword(s):  
Boundary Layer ◽  
Friction Coefficient ◽  
Wind Tunnel ◽  
Skin Friction Coefficient ◽  
Boundary Layer Transition ◽  
Layer Transition ◽  
Supersonic Wind Tunnel ◽  
Oil Film ◽  
Naca0012 Airfoil ◽  
Roughness Elements

The influence of distributed cylinder roughness elements on boundary layer transition for NACA0012 airfoil at Ma = 0.6 has been investigated by subsonic/transonic/supersonic wind tunnel experiment with oil-film interferometry. Three different heights and two different distances of cylinder roughness elements on the airfoil model were used, and the skin friction coefficient was measured by the oil-film interferometry. The experimental results show that higher roughness elements promote the transition earlier. In addition, narrower distance of roughness elements can delay the transition compared with the case of wider distance.

The Effects of a Trip Wire and Unsteadiness on a High Speed Highly Loaded Low-Pressure Turbine Blade

2004 ◽  
Author(s):  
M. Vera ◽  
H. P. Hodson ◽  
R. Vazquez
Keyword(s):  
Boundary Layer ◽  
High Speed ◽  
Low Pressure ◽  
Boundary Layer Transition ◽  
Layer Transition ◽  
Low Pressure Turbine ◽  
Roughness Elements ◽  
Unsteady Inflow ◽  
Mach Numbers ◽  
Inflow Conditions

This paper presents the effect of a single spanwise 2D wire upon the downstream position of boundary layer transition under steady and unsteady inflow conditions. The study is carried out on a high turning, high-speed, low pressure turbine (LPT) profile designed to take account of the unsteady flow conditions. The experiments were carried out in a transonic cascade wind tunnel to which a rotating bar system had been added. The range of Reynolds and Mach numbers studied includes realistic LPT engine conditions and extends up to the transonic regime. Losses are measured to quantify the influence of the roughness with and without wake passing. Time resolved measurements such as hot wire boundary layer surveys and surface unsteady pressure are used to explain the state of the boundary layer. The results suggest that the effect of roughness on boundary layer transition is a stability governed phenomena, even at high Mach numbers. The combination of the effect of the roughness elements with the inviscid Kelvin-Helmholtz instability responsible for the rolling up of the separated shear layer (Stieger [1]) is also examined. Wake traverses using pneumatic probes downstream of the cascade reveal that the use of roughness elements reduces the profile losses up to exit Mach numbers of 0.8. This occurs with both steady and unsteady inflow conditions.

On the Mechanics and Control of Boundary Layer Transition induced by Discrete Roughness Elements

2017 ◽  
Author(s):  
Saikishan Suryanarayanan ◽  
David B. Goldstein ◽  
Garry L. Brown ◽  
Alexandre R. Berger ◽  
Edward B. White
Keyword(s):  
Boundary Layer ◽  
Boundary Layer Transition ◽  
Layer Transition ◽  
Roughness Elements ◽  
And Control ◽  
Discrete Roughness Elements
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