Résumé of the AIAA FDTC Low Reynolds Number Discussion Group's Canonical Cases

Ol, Michael V.; Altman, Aaron; Eldredge, Jeff D.; Garmann, Daniel J.; Lian, Yongsheng

doi:10.2514/6.2010-1085

Cited by 50 publications

(51 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A strong dependence of the LEV circulation and the resulting forces on the reduced frequency (defined as πfc/U ∞ ) has been well documented (Ol et al 2010;Baik et al 2012;Granlund et al 2013;Jantzen et al 2014). For example, Baik et al (2012) and Jantzen et al (2014) concluded that the reduced frequency is the primary parameter governing the flow evolution and the unsteady force generation on a flat plate with sufficient forcing and large effective angle of attack.…”

Section: Leading-edge Vortex Dynamicsmentioning

confidence: 94%

Vortex formation and shedding from a cyber-physical pitching plate

Onoue

Breuer

2016

J. Fluid Mech.

View full text Add to dashboard Cite

We report on the dynamics of the formation and growth of the leading-edge vortex and the corresponding unsteady aerodynamic torque induced by large-scale flow-induced oscillations of an elastically mounted flat plate. All experiments are performed using a high-bandwidth cyber-physical system, which enables the user to access a wide range of structural dynamics using a feedback control system. A series of two-dimensional particle image velocimetry measurements are carried out to characterize the behaviour of the separated flow structures and its relation to the plate kinematics and unsteady aerodynamic torque generation. By modulating the structural properties of the cyber-physical system, we systematically analyse the formation, strength and separation of the leading-edge vortex, and the dependence on kinematic parameters. We demonstrate that the leading-edge vortex growth and strength scale with the characteristic feeding shear-layer velocity and that a potential flow model using the measured vortex circulation and position can, when coupled with the steady moment of the flat plate, accurately predict the net aerodynamic torque on the plate. Connections to previous results on optimal vortex formation time are also discussed.

show abstract

Section: Leading-edge Vortex Dynamicsmentioning

confidence: 94%

Vortex formation and shedding from a cyber-physical pitching plate

Onoue

Breuer

2016

J. Fluid Mech.

View full text Add to dashboard Cite

show abstract

“…As such, a flat-plate boundary layer with corresponding boundary-layer vorticity is the initial condition for this first test case. Note that the insensitivity of the chosen ramp-up motion on the resulting lift forces has been shown by Jones & Babinsky (2010) and Ol et al (2010) for rotating and translating wings, respectively.…”

Section: Experimental Methodsmentioning

confidence: 94%

On the persistence of memory: do initial conditions impact vortex formation?

2013

View full text Add to dashboard Cite

An investigation into redistribution of vorticity for rapidly accelerating plates with varying kinematics and initial conditions has been performed. Both threedimensional particle tracking velocimetry and direct force measurements were applied simultaneously. The effective velocity of the feeding shear layer has been identified as the appropriate characteristic velocity rather than the commonly used plunge or free stream velocity. Based on this new normalization for circulation, it has been demonstrated that the existence of initial boundary-layer vorticity on the plunging plate -at least in the near-midplane region -does not contribute to the eventual vortex formation process. In accordance with the literature, however, the tip vortex positioning relative to the plate surface has been identified as an important contributor in the overall force production, particularly once the plate acceleration has ceased.

show abstract

“…The accuracy of these prediction methods depends on a thorough understanding of the flow around airfoils, specifically, the evolution of leading edge vortices (LEVs). Several studies have also been dedicated to the investigation of how the LEV develops on the suction side of the airfoil during the pitch motion Yilmaz and Rockwell (2012); Ol et al (2010); Hord and Lian (in press); Shyy et al (2009);Baik et al (2012). These studies investigated the number of items that affect LEV development; however, few attempts have been tried to understand the relationship between LEV size and the pitch rate and it's resulting in lift generation.…”

Section: Introductionmentioning

confidence: 99%

Leading edge vortex development on a pitch-up airfoil

Hord¹,

Lian²

2015

IJAD

Self Cite

View full text Add to dashboard Cite

Abstract:The development of the lift generated by a leading edge vortex (LEV) across a flat plate experiencing a pitch-up motion is investigated to understand the LEV's influence on lift generation. The flow field around the pitch-up plate is simulated by solving the Navier-Stokes equations on composite overlapping grids. The pitch-up angle was from 0 to 45 degrees and the Reynolds number was 500. The Q-criterion method was used to isolate vortex structures from shear layer vortices in order to assess the circulation of the LEV. The calculated circulation due to LEV was then compared to the computed lift from simulation for a better understanding of the effect of the LEV on lift generation. Using the non-circulatory component of Theodorsen's theory, we separate the total lift into lift due to the plate rotation (non-circulatory lift) and lift due to aerodynamic effects (circulatory lift). Our results showed that the non-circulatory force only contributes 10-20% of the total lift and the remaining is due to the LEV. We also found that the LEV growth mainly depends on time but not the angle of attack. However, the circulation strength of the LEV depends on the pitch rate.

show abstract

Résumé of the AIAA FDTC Low Reynolds Number Discussion Group's Canonical Cases

Cited by 50 publications

References 10 publications

Vortex formation and shedding from a cyber-physical pitching plate

Vortex formation and shedding from a cyber-physical pitching plate

On the persistence of memory: do initial conditions impact vortex formation?

Leading edge vortex development on a pitch-up airfoil

Contact Info

Product

Resources

About