Dynamic Stall Experiments on Oscillating Airfoils

Mccroskey, W. J.; Carr, L. W.; Mcalister, K. W.

doi:10.2514/3.61332

Cited by 398 publications

(159 citation statements)

References 10 publications

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“…Experimental studies have continued to provide very important insights into the physics of the dynamic stall process. McCroskey et al [24] studied incompressible boundary layer separation using oil smoke visualization and described the three different types of boundary layer separation observed in the case of an oscillating airfoil. Acharya and Metwally [1] categorized and quantified the sources of vorticity and identified the key mechanisms in the initiation, development, growth and movement of the dynamic stall vortex.…”

Section: Literature Surveymentioning

confidence: 99%

Effects of compressibility, pitch rate, and Reynolds number on unsteady incipient leading-edge boundary layer separation over a pitching airfoil

Choudhuri

Knight

1996

J. Fluid Mech.

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Public reporting burden for this collection of information is estimated to average 1 hour per respoinse. including the time for reviewing instructions. searching existing data sources. gathering and maintaining the data needed, and comoleting anrd ryaevwing the collection of information. Send comments re< arding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden. SUPPLEMENTARY NOTESThe view, opinions and/or findings contained in this report are those of the author(s) and should not be construed as an official Department of the Army position, policy,--or decision, -unless so designated by other documentation. 12a. DISTRIBUTION /AVAILABILITY STATEMENT 12b. DISTRIBUTION CODEApproved for public release; distribution unlimited. ABSTRACT (M-xiMum200words)The effects of compressibility, pitch rate and Reynolds number on the initial stages of 2-D unsteady separation of laminar subsonic flow over a pitching NACA-0012 airfoil have been studied numerically. Computations have been performed using two separate algorithms (structured grid algorithm of Beam and Warming, and unstructured grid algorithm employing fluxdifference splitting method of Roe) for the compressible laminar NavierStokes equations. The simulations show the appearance of a primary recirculating region near the leading edge, followed by a secondary and tertiary recirculating regions. The primary and secondary recirculating regions interact with each other to give rise to the unsteady separation of the boundary layer. Increasing the Mach number from 0.2 to 0,5 causes a delay in the formation of the primary recirculating region. Increasing the pitch rate also delays the formation. Increasing the Reynolds number hastens the appearance of the primary recirculating region and leads to the appearance of a shock on the top surface alon g with the formation of multiple recirculating regions near the leading edge. A linear stability anal ,sis has shown that the appearance of the primary recirculating region is related

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Section: Literature Surveymentioning

confidence: 99%

Effects of compressibility, pitch rate, and Reynolds number on unsteady incipient leading-edge boundary layer separation over a pitching airfoil

Choudhuri

Knight

1996

J. Fluid Mech.

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“…We shall call this limitfollows: (1) static data at discrete ing case 'deep dynamic stall"; it corvalues of a for X. -0.11, 0.185, 0.25, responds to the 4fully-developed" vortex, and 0.30; (2) unsteady data with or vortex-dominated, cases that were a- 15 Table 1. The airloads 3 max is slightly greater than the static typically exhibit significant amounts of stall angle and dynamic stall occurs at hysteresis, and negative aerodynamic low frequencies but possibly disappears damping is more likely to occur than in as k increases; (6) variations in both a.…”

Section: As~ J CLmentioning

confidence: 99%

Dynamic Stall on Advanced Airfoil Sections

Mccroskey¹,

Mcalister²,

Carr³

et al. 1981

j am helicopter soc

160

104

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Abstractwall interference, and experimental uncertainties. These are serious problems even The dynamic stall characteristics of for static stall, as indicated by the eight airfoils have been investigated in results plotted in Fig. 1 for two very sinusoidal pitch oscillations over a wide different airfoils. The shaded band shows, range of two-dimensional unsteady flow for the classical NACA 0012, the spread of conditions. The results provide a unique measured values of the maximum lift coefcomparison of the effects of section geomficient from our experiment and from those etry in a simulated rotor environment, reported previously.

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“…McCroskey et al (McCroskey et al 1976) explained this behaviour as the phase shift and it is strongly influenced by the reduced frequency. Bangga and Sasongko (Bangga and Sasongko 2012) performed CFD simulations of an oscillating rotocraft airfoil at a reduced frequency of 0.62.…”

Section: Dynamic Stall Mechanismmentioning

confidence: 99%

“…In the late of 1970s, Friedmann (Friedmann 1983) described three models and, afterwards, mathematical modelling on dynamic stall was developing (Hansen et al 2004). The models ranged from fromsimple to complex such as ONERA (Petot 1989), Boeing (Friedmann 1983), Johnson (Johnson and Ham 1972;McCroskey et al 1976), Øye (Øye 1991), Risø (Hansen et al 2004) and also Leishman-Beddoes models (Leishman and Beddoes 1989;Hansen et al 2004).…”

Section: Introductionmentioning

confidence: 99%

Dynamic Stall Prediction of a Pitching Airfoil using an Adjusted Two-Equation URANS Turbulence Model

Bangga

Sasongko

2017

JAFM

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The necessity in the analysis of dynamic stall becomes increasingly important due to its impact on many streamlined structures such as helicopter and wind turbine rotor blades. The present paper provides Computational Fluid Dynamics (CFD) predictions of a pitching NACA 0012 airfoil at reduced frequency of 0.1 and at small Reynolds number value of 1.35e5. The simulations were carried out by adjusting the k − ε URANS turbulence model in order to damp the turbulence production in the near wall region. The damping factor was introduced as a function of wall distance in the buffer zone region. Parametric studies on the involving variables were conducted and the effect on the prediction capability was shown. The results were compared with available experimental data and CFD simulations using some selected two-equation turbulence models. An improvement of the lift coefficient prediction was shown even though the results still roughly mimic the experimental data. The flow development under the dynamic stall onset was investigated with regards to the effect of the leading and trailing edge vortices. Furthermore, the characteristics of the flow at several chords length downstream the airfoil were evaluated.

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Dynamic Stall Experiments on Oscillating Airfoils

Cited by 398 publications

References 10 publications

Effects of compressibility, pitch rate, and Reynolds number on unsteady incipient leading-edge boundary layer separation over a pitching airfoil

Effects of compressibility, pitch rate, and Reynolds number on unsteady incipient leading-edge boundary layer separation over a pitching airfoil

Dynamic Stall on Advanced Airfoil Sections

Dynamic Stall Prediction of a Pitching Airfoil using an Adjusted Two-Equation URANS Turbulence Model

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