scholarly journals Validation of High-Speed Turbulent Boundary Layer and Shock-Boundary Layer Interaction Computations with the OVERFLOW Code

2006 ◽  
Author(s):  
A. Brandon Oliver ◽  
Randolph Lillard ◽  
Gregory Blaisdell ◽  
Anastasios Lyrintzis
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
High Speed ◽  
Layer Interaction ◽  
Shock Boundary Layer Interaction ◽  
Boundary Layer Interaction

Three-dimensional instantaneous structure of a shock wave/turbulent boundary layer interaction

2009 ◽  
Vol 622 ◽  
pp. 33-62 ◽  
Author(s):  
R. A. HUMBLE ◽  
G. E. ELSINGA ◽  
F. SCARANO ◽  
B. W. van OUDHEUSDEN
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Turbulent Boundary Layer ◽  
High Speed ◽  
Large Scale ◽  
Three Dimensional ◽  
Reflected Shock Wave ◽  
Layer Interaction ◽  
Reflected Shock ◽  
Boundary Layer Interaction

An experimental study is carried out to investigate the three-dimensional instantaneous structure of an incident shock wave/turbulent boundary layer interaction at Mach 2.1 using tomographic particle image velocimetry. Large-scale coherent motions within the incoming boundary layer are observed, in the form of three-dimensional streamwise-elongated regions of relatively low- and high-speed fluid, similar to what has been reported in other supersonic boundary layers. Three-dimensional vortical structures are found to be associated with the low-speed regions, in a way that can be explained by the hairpin packet model. The instantaneous reflected shock wave pattern is observed to conform to the low- and high-speed regions as they enter the interaction, and its organization may be qualitatively decomposed into streamwise translation and spanwise rippling patterns, in agreement with what has been observed in direct numerical simulations. The results are used to construct a conceptual model of the three-dimensional unsteady flow organization of the interaction.

scholarly journals Experimental Unsteady Shock-Boundary Layer Interaction at Single Blades and in Linear Cascades

1986 ◽  
Author(s):  
H. E. Gallus ◽  
K.-D. Broichhausen ◽  
J. M. Henne
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Unsteady Flow ◽  
High Speed ◽  
Layer Interaction ◽  
Shock Boundary Layer Interaction ◽  
Boundary Layer Interaction ◽  
Gradient Technique ◽  
Unsteady Viscous Flow ◽  
Flow Effects

Self-excited vibrations of transonic blading in turbomachines are partly due to unsteady viscous flow effects and shock-boundary layer interaction. To investigate the unsteady flow, experiments have been performed in a transonic windtunnel at single blades and in a cascade, where the central blade is either mounted elastically or driven by electromagnetic shakers to torsional vibration. The unsteady flow is measured by a stroboscopic schlieren-method including high-speed movies and a recently developed laser-density gradient-technique. The vibration of the blade is controlled by strain gauges. The test results reveal: - severe shock wave and boundary layer oscillations occur with separation alternating between shock-induced and trailing edge separation, - the unsteadiness of the flow largely depends on Mach- and Reynolds number, - with pitching vibration of the blade, forced and self-excited shock wave oscillations interfere with each other.

scholarly journals Shock Boundary Layer Interaction on High Turning Transonic Turbine Cascades

1979 ◽  
Author(s):  
C. G. Graham ◽  
F. H. Kost
Keyword(s):  
Boundary Layer ◽  
High Speed ◽  
Work Capacity ◽  
Layer Interaction ◽  
Shock Boundary Layer Interaction ◽  
Boundary Layer Interaction ◽  
High Speed Film ◽  
Transonic Turbine ◽  
Performance Penalty ◽  
Rotor Profiles

In recent years, the increase in turbine entry temperature, coupled with the capability of higher blade speeds, has led to greater interest in the high work capacity single-stage transonic high pressure turbine. However, the transonic turbine has a performance penalty compared with an equivalent subsonic unit due mainly to shock induced losses. A cascade investigation into the influence of supersonic shocks on turbine blade performance is reported. Two different rotor profiles designed for the same duty were tested in the rectilinear cascade wind tunnel at DFVLR-AVA Goettingen. The results indicate the sensitivity of the cascade performance to shock boundary layer interaction. The importance of Schlieren optics flow visualization (including high-speed film to show the unsteady behavior of the flow) in evaluating the results is discussed.

Highly separated axisymmetric step shock-wave/turbulent-boundary-layer interaction

2017 ◽  
Vol 828 ◽  
pp. 236-270 ◽  
Author(s):  
Gaurav Chandola ◽  
Xin Huang ◽  
David Estruch-Samper
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Turbulent Boundary Layer ◽  
High Speed ◽  
Large Scale ◽  
Scale Separation ◽  
Time Resolved ◽  
Layer Interaction ◽  
Boundary Layer Interaction ◽  
High Reynolds

The unsteadiness of a shock-wave/turbulent-boundary-layer interaction induced by an axisymmetric step (cylinder/$90^{\circ }$-disk) is investigated experimentally at Mach 3.9. A large-scale separation of the order of previously reported incoming turbulent superstructures is induced ahead of the step ${\sim}30\unicode[STIX]{x1D6FF}_{o}$ and followed by a downstream separation of ${\sim}10\unicode[STIX]{x1D6FF}_{o}$ behind it, where $\unicode[STIX]{x1D6FF}_{o}$ is the incoming boundary-layer thickness. Narrowband high-frequency instabilities shift gradually to more moderate frequencies along the upstream separation region exhibiting a strong predominance of shear-induced disturbance levels – arising between the outer high-speed flow and the subsonic bubble. Through spectral/time-resolved analysis of this high Reynolds number and large-scale separation, results offer new insights into the shear layer’s inception and evolution (convection, growth and instability) and its influence on interaction unsteadiness.

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