Flow visualization and pressure measurements on an airfoil in high Reynolds number transonic flow

2002 ◽  
Author(s):  
H. Olivier ◽  
T. Reichel ◽  
M. Zechner
Keyword(s):  
Reynolds Number ◽  
Flow Visualization ◽  
Transonic Flow ◽  
High Reynolds Number ◽  
Pressure Measurements ◽  
High Reynolds

Airfoil Flow Visualization and Pressure Measurements in High-Reynolds-Number Transonic Flow

AIAA Journal ◽  
2003 ◽  
Vol 41 (8) ◽  
pp. 1405-1412 ◽  
Author(s):  
Herbert Olivier ◽  
Thomas Reichel ◽  
Mitja Zechner
Keyword(s):  
Reynolds Number ◽  
Flow Visualization ◽  
Transonic Flow ◽  
High Reynolds Number ◽  
Pressure Measurements ◽  
Airfoil Flow ◽  
High Reynolds

Measurements of the Tip Clearance Flow for a High-Reynolds-Number Axial-Flow Rotor

1995 ◽  
Vol 117 (4) ◽  
pp. 522-532 ◽  
Author(s):  
W. C. Zierke ◽  
K. J. Farrell ◽  
W. A. Straka
Keyword(s):  
Reynolds Number ◽  
Flow Visualization ◽  
Vortex Core ◽  
Rotor Blade ◽  
High Reynolds Number ◽  
Tip Clearance ◽  
Tip Leakage Vortex ◽  
Tip Leakage ◽  
Blade Tip ◽  
High Reynolds

A high-Reynolds-number pump (HIREP) facility has been used to acquire flow measurements in the rotor blade tip clearance region, with blade chord Reynolds numbers of 3,900,000 and 5,500,000. The initial experiment involved rotor blades with varying tip clearances, while a second experiment involved a more detailed investigation of a rotor blade row with a single tip clearance. The flow visualization on the blade surface and within the flow field indicate the existence of a trailing-edge separation vortex, a vortex that migrates radially upward along the trailing edge and then turns in the circumferential direction near the casing, moving in the opposite direction of blade rotation. Flow visualization also helps in establishing the trajectory of the tip leakage vortex core and shows the unsteadiness of the vortex. Detailed measurements show the effects of tip clearance size and downstream distance on the structure of the rotor tip leakage vortex. The character of the velocity profile along the vortex core changes from a jetlike profile to a wakelike profile as the tip clearance becomes smaller. Also, for small clearances, the presence and proximity of the casing endwall affects the roll-up, shape, dissipation, and unsteadiness of the tip leakage vortex. Measurements also show how much circulation is retained by the blade tip and how much is shed into the vortex, a vortex associated with high losses.

Well Resolved Wall Pressure Measurements in a High Reynolds Number Turbulent Boundary Layer

2004 ◽  
Author(s):  
Brendan F. Perkins
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Turbulent Boundary Layer ◽  
Surface Pressure ◽  
High Reynolds Number ◽  
Wall Pressure ◽  
Pressure Measurements ◽  
Boundary Layer Turbulence ◽  
High Reynolds ◽  
Salt Playa

In order to better understand boundary layer turbulence at high Reynolds number, the fluctuating wall pressure was measured within the turbulent boundary layer that forms over the salt playa of Utah’s west desert. Pressure measurements simultaneously acquired from an array of nine microphones were analyzed and interpreted. The wall pressure intensity was computed and compared with low Reynolds number data. This analysis indicated that the variance in wall pressure increases logarithmically with Reynolds number. Computed autocorrelations provide evidence for a hierarchy of surface pressure producing scales. Space-time correlations are used to compute broadband convection velocities. The convection velocity data indicate an increasing value for larger sensor separations. To the author’s knowledge, the pressure measurements are the highest Reynolds number, well resolved measurements of fluctuating surface pressure to date.

Development of a New Algorithm for Modeling Viscous Transonic Flow on Unstructured Grids at High Reynolds Numbers

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Rozie Zangeneh
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Turbulent Flows ◽  
Transonic Flow ◽  
High Reynolds Number ◽  
Unstructured Grids ◽  
Separation Bubble ◽  
Aircraft Design ◽  
Finite Volume Scheme ◽  
High Reynolds

Abstract This study investigates a new algorithm for modeling viscous transonic flow at high Reynolds number cases suitable for unstructured grids. The challenge of modeling viscous transonic flow around airfoils becomes intense at high Reynolds number cases due to a variety of flow regimes encountered, such as boundary layer growth and the shockwave/turbulent boundary-layer interaction, accompanied by large separation bubble. Therefore, it is highly demanded to develop robust and efficient models that can capture the shock-induced problems of turbulent flows for aircraft design purposes. The new model is essentially a hybrid algorithm to address the conflict between turbulence modeling and shock-capturing requirements. A skew-symmetric form of a collocated finite volume scheme with minimum aliasing errors was implemented to model the turbulent region in the combination of a semidiscrete, central difference scheme to capture discontinuities with adequately low numerical dissipation for the minimal effect on turbulent flows. To evaluate the effectiveness of the model, it was tested in three conventional cases. The computational results are close to measured data for predicting the shock locations. This implies that the model is able to predict the scale of the separation bubble and the main characteristics of turbulent transonic flow adequately.

scholarly journals Shock-vortex shear-layer interaction in the transonic flow around a supercritical airfoil at high Reynolds number in buffet conditions

2015 ◽  
Vol 55 ◽  
pp. 276-302 ◽  
Author(s):  
Damien Szubert ◽  
Fernando Grossi ◽  
Antonio Jimenez Garcia ◽  
Yannick Hoarau ◽  
Julian C.R. Hunt ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Shear Layer ◽  
Transonic Flow ◽  
High Reynolds Number ◽  
Supercritical Airfoil ◽  
Layer Interaction ◽  
High Reynolds

Measurements of the Tip Clearance Flow for a High Reynolds Number Axial-Flow Rotor: Part 1 — Flow Visualization

1994 ◽  
Author(s):  
W. C. Zierke ◽  
K. J. Farrell ◽  
W. A. Straka
Keyword(s):  
Reynolds Number ◽  
Flow Visualization ◽  
Rotor Blade ◽  
High Reynolds Number ◽  
Rotor Blades ◽  
Tip Clearance ◽  
Trailing Edge ◽  
Tip Leakage ◽  
High Reynolds ◽  
Edge Separation

A high Reynolds number pump (HIREP) facility has been used to acquire flow measurements in the rotor blade tip clearance region-with blade chord Reynolds numbers of 3,900,000 and 5,500,000. The initial experiment involved rotor blades with varying tip clearances, while a second experiment involved a more detailed investigation of a rotor blade row with a single tip clearance. This paper focuses on flow visualization, employing techniques unique for use in water. The flow visualization on the blade surface and within the flow field indicate that the combination of centripetal acceleration and separation near the trailing edge of the rotor blade suction surface results in the formation of a trailing-edge separation vortex-a vortex which migrates radially upwards along the trailing edge and then turns in the circumferential direction near the casing, moving in the opposite direction of blade rotation. Flow visualization also helps in establishing the trajectory of the tip leakage vortex core. The trailing-edge separation vortex, which lies closer to the endwall than the tip leakage vortex, seems to have an influence on this trajectory. Finally, the periodic interaction of the rotor blades with wakes from the upstream inlet guide vanes-as well as freestream turbulence and vortex structure instabilities-affects the unsteadiness of the vortex.

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