Inboard Stall Delay Due to Rotation

Dumitrescu, Horia; Cardoş, Vladimir

doi:10.5772/18632

Cited by 9 publications

(8 citation statements)

References 33 publications

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“…The flow field at the blade root can be divided as a potential and a viscous flow regions where the latter includes the boundary layer of the blade and the wake. Many studies performed in the root region focus on the analysis of the boundary layer mechanisms such as stall delay (e.g., Dumitrescu & Cardos , Dumitrescu et al ., and Hu et al . ).…”

Section: Introductionmentioning

confidence: 99%

“…). For example, Dumitrescu et al analyzed the boundary layer characteristics of a wind turbine blade root region by discussing the 3‐D and rotational effects for both attached and separated flows. Schreck et al combined the surface pressure measurements with the computations enabled to have high‐resolution boundary layer topologies and detailed above surface flow field structures.…”

Section: Introductionmentioning

confidence: 99%

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Experimental investigation of the root flow in a horizontal axis wind turbine

et al. 2013

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This research investigates the flow behavior and its features in the blade's root region of a horizontal axis wind turbine by using stereoscopic particle image velocimetry (PIV) technique. Wind tunnel tests are conducted to measure the velocity field, phase-locked with the blade motion, at different azimuth angles and at different spanwise positions. The pressure distribution is obtained from PIV velocity field by solving the Navier-Stokes momentum equations. In this paper, we aim to answer two questions: (i) How is the flow behavior in the root region? (ii) How is the evolution of the root vortex? The analysis of the velocity fields shows an outboard radial flow motion in the root region and a vorticity driven inboard motion at the bladeŠs maximum chord position. As a result of this vorticity driven flow, an increase in the axial velocity close to nacelle is measured. Wake sheets are observed and further discussed in the measured velocity and vorticity distributions. The formation and evolution of the root vortices conveyed downstream by the axial velocity are analyzed through vorticity and pressure distributions. Although the azimuthal vorticity in 3D representation is showing the trailing vorticity, the tilting of the root vortex tube is observed in the axial vorticity distribution. Moreover, the radial vorticity and azimuthal velocity from chordwise measurements show separation on the suction surface of the blade. This research concluded that the flow in the blade wake is driven by the root vortex; hence, the local effects of the root vortex cannot be ignored.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental investigation of the root flow in a horizontal axis wind turbine

et al. 2013

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“…The limiting streamlines of the surface help to see the blade tip and root flows generated by low and high-speed winds [11]. Dumitrescu and Cardos [12] concluded that the flow visualization was attached over the rotor, at low wind speed conditions. At about 0.17 to 0.31 of the radius of the rotor, the secondary stream reaches the fastest.…”

Section: Introductionmentioning

confidence: 99%

“…Several simulation studies on the 3-D effect of stall delays have been discussed. For low velocities HAWT, some researchers [12] have found that stall propagates from the base of the blade to the tip. Wu et al have completed a study of the dynamic eddy arrangement during stall postponements [13].…”

Section: Introductionmentioning

confidence: 99%

Investigation of Rolled-Up Effect of the Forward-Swept 3-D Wind Turbine Blades

Sutrisno¹

2018

IJRET

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Noiseless aerodynamics of a rotor blade is a vital research objective towards environmentally friendly wind turbine technology and military advancement of helicopter blades. Blade planform of a wind turbine determines the limiting streamline that responsible for the aerodynamic characteristics. This paper focused on the aerodynamic flow visualization showing the flow pattern around forward swept horizontal axis wind turbine (HAWT) for different radius and different wind velocities. The experiments were conducted in a wind tunnel. Tuft patterns were used for flow visualization, and rope brake dynamometer was employed for measuring the performances in different wind speeds. It is found that the planforms can form 3-D folds streamline that show the detailed mechanism of rolling-up effect, and give different performances in the cases of different radius and wind speeds.

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“…Corten, through an order of magnitude analysis of the Navier–Stokes equations for non‐inertial boundary layers, predicted that in the case of rotation, the separation point moves downstream. Dumitreschu et al also called the effect ‘stall‐delay’, suggesting that Coriolis force causes a downstream shift in the location of the separation point in rotation.…”

Section: Introductionmentioning

confidence: 99%

Comments on the research article by Grosset al.(2012)

Guntur

Sørensen

2013

Wind Energ.

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The purpose of this Letter to the Editor is to present a discussion on the physics of rotational augmentation based on existing work. One of the latest works by Gross et al. (2012) is highlighted here, and its conclusions are discussed. Based on the existing understanding of rotational augmentation, some inconsistencies seem to be present in the analysis of Gross et al. These are identified and discussed here, along with a brief survey of relevant literature.

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Inboard Stall Delay Due to Rotation

Cited by 9 publications

References 33 publications

Experimental investigation of the root flow in a horizontal axis wind turbine

Experimental investigation of the root flow in a horizontal axis wind turbine

Investigation of Rolled-Up Effect of the Forward-Swept 3-D Wind Turbine Blades

Comments on the research article by Grosset al.(2012)

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