An unsteady airfoil theory applied to pitching motions validated against experiment and computation

Ramesh, Kiran; Gopalarathnam, Ashok; Edwards, Jack R.; Ol, Michael V.; Granlund, Kenneth

doi:10.1007/s00162-012-0292-8

Cited by 102 publications

(91 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As the pivot location is varied along the chord from leading to trailing edge, the pitch angle at LEV initiation is seen to increase. This behavior is due to the effect of increased motion-induced "downwash" at the leading edge as the pivot is moved aftward, a trend known from earlier works [46,57]. Clearly, there is no obvious relation between initiation of LEV formation and the values of the pitch angle at that time instant.…”

Section: Case Study 1: Effect Of Pivot Locationmentioning

confidence: 88%

“…The computations were performed on a 2-D body-fitted mesh containing 92,400 cells. REACTMB-INS has been used for a wide variety of CFD problems, including unsteady aerodynamics [52,57], two-phase flows [10], human-induced contaminant transport [12,13], and moving-body flows [14].…”

Section: Computational and Experimental Methodsmentioning

confidence: 99%

“…A new theoretical method based on the unsteady thin-airfoil theory developed by Katz and Plotkin [38], accounting for large amplitudes of motion and nonplanar wakes was developed by the Ramesh et al [57] and applied to a ramp-hold-return pitching maneuver. The results from this model were compared against those from Reynolds-averaged Navier-Stokes computational fluid dynamics (CFD) and experimental (water tunnel) methods.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Leading-edge flow criticality as a governing factor in leading-edge vortex initiation in unsteady airfoil flows

Ramesh

Granlund

et al. 2017

Theor. Comput. Fluid Dyn.

Self Cite

View full text Add to dashboard Cite

A leading-edge suction parameter (LESP) that is derived from potential flow theory as a measure of suction at the airfoil leading edge is used to study initiation of leading-edge vortex (LEV) formation in this article. The LESP hypothesis is presented, which states that LEV formation in unsteady flows for specified airfoil shape and Reynolds number occurs at a critical constant value of LESP, regardless of motion kinematics. This hypothesis is tested and validated against a large set of data from CFD and experimental studies of flows with LEV formation. The hypothesis is seen to hold except in cases with slow-rate kinematics which evince significant trailing-edge separation (which refers here to separation leading to reversed flow on the aft portion of the upper surface), thereby establishing the envelope of validity. The implication is that the critical LESP value for an airfoil-Reynolds number combination may be calibrated using CFD or experiment for just one motion and then employed to predict LEV initiation for any other (fast-rate) motion. It is also shown that the LESP concept may be used in an inverse mode to generate motion kinematics that would either prevent LEV formation or trigger the same as per aerodynamic requirements.

show abstract

Section: Case Study 1: Effect Of Pivot Locationmentioning

confidence: 88%

Section: Computational and Experimental Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Leading-edge flow criticality as a governing factor in leading-edge vortex initiation in unsteady airfoil flows

Ramesh

Granlund

et al. 2017

Theor. Comput. Fluid Dyn.

Self Cite

View full text Add to dashboard Cite

show abstract

“…In previous work, the authors developed an unsteady airfoil theory which accounted for large amplitudes and nonplanar wakes, 25 and proposed the Leading Edge Suction Parameter (LESP) criterion 26 to predict the onset of LEV formation. For a given Reynolds number and airfoil, it was shown that LEV formation is always initiated at the same value of LESP (calculated from inviscid theory), regardless of motion kinematics.…”

mentioning

confidence: 99%

Theoretical Analysis of Perching and Hovering Maneuvers

Ramesh

Gopalarathnam

Edwards

et al. 2013

31st AIAA Applied Aerodynamics Conference

Self Cite

View full text Add to dashboard Cite

“…MPI is used to achieve parallel computation on a cluster. The original version of the solver has been used in the study of a wide variety of CFD problems, including unsteady aerodynamics [13,14], two-phase flows [15], and human-induced contaminant transport [16,17]. An immersed-boundary method [11] is incorporated to enable computations of flow about moving objects.…”

Section: Introductionmentioning

confidence: 99%