Investigation of unsteady wake-separated boundary layer interaction using particle-image-velocimetry

Date

2007-05-17

Author

Uzol, Oğuz
Cranstone, Alex
Hodson, Howard

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

301
views

0
downloads

The current paper presents an experimental investigation of the interaction between unsteady wakes and the separated boundary layer on the suction side of an ultra-high-lift low-pressure turbine airfoil. Two-dimensional Particle Image Velocimetry (PIV) measurements of the unsteady boundary layer over the T106C LP turbine profile were performed in a low speed linear cascade facility, at selected phases of passing wakes. The wakes are created by moving cylindrical bars across the inlet of the test section. Various phenomena were investigated such as separation and transition characteristics, vortex structures within the unsteady boundary layer, their interaction and effects on the transition process, the corresponding vortex shedding mechanisms and the unsteady behaviour of the separation bubble due to the wake- boundary layer interaction. The current measurements suggest that rollup vortices are generated as the wake approaches the separated shear layer on the suction surface before the wake centerline starts impinging on the blade. At this instant, the bubble is sufficiently high for the free shear layer to roll up into a vortex and the incoming wake is highly distorted (strained) due to the velocity field within the blade passage, and the turbulence distribution within the wake is not symmetrical. Vortices within the boundary layer, identified using the swirl strength distributions calculated from the eigenvalues of the velocity gradient tensor, seem to be coalescing and forming bigger scale structures, which in turn break up into smaller but higher swirl strength eddies. In between the passing wakes, the separation bubble grows in both in height and length, trying to return to its steady state shape.

Subject Keywords

AXIAL-FLOW TURBINE, TRANSITION, BLADE, FIELD

URI

https://hdl.handle.net/11511/40190

DOI

https://doi.org/10.1115/gt2007-28099

Conference Name

52nd ASME Turbo Expo 2007

Collections

Department of Aerospace Engineering, Conference / Seminar

Suggestions

OpenMETU
Core

Measurement of the elliptic anisotropy of charged particles produced in PbPb collisions at root s(NN)=2.76 TeV Chatrchyan, S.; et. al. (2013-01-01) The anisotropy of the azimuthal distributions of charged particles produced in root s(NN) = 2.76 TeV PbPb collisions is studied with the CMS experiment at the LHC. The elliptic anisotropy parameter, upsilon(2), defined as the second coefficient in a Fourier expansion of the particle invariant yields, is extracted using the event-plane method, two- and four-particle cumulants, and Lee-Yang zeros. The anisotropy is presented as a function of transverse momentum (p(T)), pseudorapidity (eta) over a broad kinema...
Estimation of lining thickness around circular shafts Ozturk, H; Unal, E (2001-06-22) In this paper, the broken zone developing, around a circular mine shafts and lining pressure is estimated by integrating the results of numerical analysis and the "rock-load height" equation derived from empirical analysis. During numerical modelling studies, the computer program FLAC(2D) was utilized. In order to estimate equivalent Mohr failure Envelope from the generalised Hoek Brown failure criterion, a new FISH function was written within FLAC(2D). Parametric studies were carried out by considering mRM...
Investigation of the effect of structural damping on wind turbine wind-induced fatigue loads Kocan, Cagri; Özgen, Gökhan Osman (2022-09-01) This paper presents a quantitative investigation of the effect of structural damping ratios of the tower and blade vibration modes of wind turbines on wind-induced fatigue loads at critical blade and tower sections. Fatigue loads are used as a relative measure of fatigue life in wind turbine design applications. By increasing the structural damping ratio of each one of the critical structural modes which highly contribute to the overall vibration response, short-term and lifetime fatigue loads at critical t...
Experimental investigation of surface roughness effects on the flow boiling of R134a in microchannels Jafari, Rahim; Okutucu Özyurt, Hanife Tuba; Ünver, Hakkı Özgür; Bayer, Özgür (2016-12-01) This study experimentally investigates the effect of surface roughness on the hydrodynamic and thermal performance of microchannel evaporators. Three micro-evaporators of the same dimensions and different surface roughness have been fabricated by micro-WEDM. Each micro-evaporator consists of forty rectangular microchannels of 700 mu m height, 250 mu m width, and 19 mm length. A microscale vapor compression refrigeration cycle has been constructed to carry out the experiments. R134a is used as the refrigeran...
Experimental and numerical analysis of a bolted connection in steel transmission towers Baran, Eray; Sen, Gokmen; Draisawi, Ammar (2016-06-01) This paper presents an integrated numerical and experimental study on a bolted splice connection used in main legs of steel lattice transmission towers. At specific locations, where the number of angle sections in built-up cross section of main leg members changes, the complex geometry around the connection region results in eccentricities in the load path and indirect load transfer. Such complex configurations and uncertainties in the load path have led to overdesigned connections with increased number of ...

Citation Formats

O. Uzol, A. Cranstone, and H. Hodson, “Investigation of unsteady wake-separated boundary layer interaction using particle-image-velocimetry,” presented at the 52nd ASME Turbo Expo 2007, Montreal, CANADA, 2007, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/40190.