Structure of turbulence within a sheared wake of a rotor blade

Date

2006-07-17

Author

Soranna, Francesco
Chow, Yi Chih
Uzol, Oğuz
Katz, Joseph

Metadata

Show full item record

Item Usage Stats

130
views

0
downloads

Stereoscopic PIV measurements examine the flow structure and turbulence within a rotor near wake located within a non-uniform field generated by a row of Inlet Guide Vanes (IGVs). The experiments are performed in a refractive index matched facility that provides unobstructed view of the entire flow field. The data are acquired at 10 closely spaced radial planes located near mid-span, enabling measurements of all the components of the phase averaged velocity and strain rate, as well as the Reynolds stress and the triple correlation tensors. The rotor wake is sheared and bent towards the pressure (inner) side by a non-uniform flow field generated by IGV wake segments that propagate along the suction and pressure sides of the rotor passage with different speeds. The axial velocity fluctuations increase along the suction/outer side of the wake, while the other components decay. On the pressure/inner part of the bent wake the circumferential velocity fluctuations are higher. The Reynolds shear stress has a complex distribution, but is higher on the suction side. The turbulent kinetic energy is also consistently higher on the outer (suction) side of the wake. This trend is fundamentally different from those observed in prior studies of curved wakes where turbulence is enhanced on the inner side of the wake due to the destabilizing effect of curvature. To explain the difference, we examine the contributors to turbulent kinetic energy production rate in a curvilinear coordinate system aligned with the wake-centerline. The contribution of streamwise curvature to the production rate of turbulent kinetic energy, although consistent with expected trends, is overwhelmed by effects of wake shearing. The primary contributor to turbulent kinetic energy production rate is the product of Reynolds shear stress with cross-stream gradients of streamwise (in a frame of reference relative to the rotor blade) velocity in the wake. The location of peak in turbulent kinetic energy is almost aligned with that of production rate. The turbulence diffusion term opposes the production rate peaks, but also has high values along the edge of the wake. Copyright © 2006 by ASME.

Subject Keywords

Flow field, Velocity fluctuations

URI

https://hdl.handle.net/11511/86453
https://www.scopus.com/record/display.uri?eid=2-s2.0-33845777987&origin=resultslist&sort=plf-f&src=s&st1=&st2=&sid=d86e55d4f52b37d92cf5ce19f217faff&sot=b&sdt=b&sl=80&s=TITLE-ABS-KEY+%28%22Structure+of+turbulence+within+a+sheared+wake+of+a+rotor+blade%22%29&relpos=0&citeCnt=0&searchTerm=

Conference Name

2nd ASME Joint U.S.-European Fluids Engineering Summer Meeting, FEDSM 2006

Collections

Department of Aerospace Engineering, Conference / Seminar

Suggestions

OpenMETU
Core

Transformation of flow structure on a delta wing of moderate sweep angle during pitch-up maneuver Yavuz, Mehmet Metin (2012-08-01) The transformation of flow structure on a delta wing of moderate sweep angle is investigated during pitch-up via quantitative imaging in crossflow planes, in relation to qualitative dye visualization. The comparisons are made with the corresponding stationary wing. The effects of different pitch-up maneuver rates and Reynolds numbers on evolution of flow patterns are also addressed. A technique of high-image-density particle image velocimetry is employed for the quantitative analysis. The transformation of ...
Effect of thickness-to-chord ratio on aerodynamics of non-slender delta wing Ghazijahani, Mohammad Sharifi; Yavuz, Mehmet Metin (2019-05-01) The effect of thickness-to-chord (t/C) ratio on aerodynamics of a non-slender delta wing with sweep angle of 45 degree is characterized in a low-speed wind tunnel using laser illuminated smoke visualization, surface pressure measurements, particle image velocimetry, and force measurements. The delta wings of t/C ratios varying from 2% to 15% with 45 degree windward beveled leading edges are tested. The results indicate that the effect of t/C ratio on flow structure is quite substantial. Considering the low ...
Effect of particle shape on fall velocity of angular particles Göğüş, Mustafa; Kokpinar, MA (2001-10-01) In this study, fall velocities of 174 regularly shaped angular particles-namely cylindrical, cubic, wedge-shaped prisms, and box-shaped prisms-made of five different materials were measured in calm water conditions in a cylindrical settling column. Reynolds numbers based on particle fall velocity and characteristic length were varied, in the range from 10(3) to 4.2 x 10(4). A new shape factor and characteristic length were defined from a transformed form of the original particle. Variation of experimentally...
TURBULENT BOUNDARY-LAYER AND THE EFFECT OF CRITICAL ROUGHNESS REYNOLDS-NUMBERS ON THE RECOVERY LENGTH BEHIND AN ISOLATED SPHERICAL ROUGHNESS ELEMENT UNDER VARIABLE PRESSURE-GRADIENT Albayrak, Kahraman (1990-03-01) The transition characteristics and the boundary layer development behind an isolated spherical roughness element were investigated in an open-circuit, suction-type wind tunnel. The experiments were performed upon a smooth aluminiuim flat plate placed in the test section of the tunnel. The desired pressure gradient was obtained by means a false roof placed in the test section. In this article, emphasis is given to the recovery length of the turbulent boundary layer behind an isolated spherical roughness ele...
High Speed Couette—Poiseuille Flow Stability in Reverse Flow Conditions Ebrinç, Ali Aslan; Özgen, Serkan; Dursunkaya, Zafer (2006-08-21) The linear stability of reverse high speed-viscous plane Couette – Poiseuille flow is investigated numerically. The conservation equations along with Sutherland’s viscosity law are studied using a second order finite difference scheme. Basic velocity and temperature distributions are perturbed by a small amplitude normal-mode disturbance. Small amplitude disturbance equations are solved numerically using a global method to find all the eigenvalues at finite Reynolds numbers. The results indicate that instab...

Citation Formats

F. Soranna, Y. C. Chow, O. Uzol, and J. Katz, “Structure of turbulence within a sheared wake of a rotor blade,” presented at the 2nd ASME Joint U.S.-European Fluids Engineering Summer Meeting, FEDSM 2006, Miami, FL; United States, 2006, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/86453.