Computational Study of the Abrupt-Wing-Stall Characteristics of F/A-18E and F-16C

Parikh, Paresh; Chung, James

doi:10.2514/1.2857

Cited by 5 publications

(6 citation statements)

References 9 publications

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“…7) shows the most sensitivity to the model. Because the current grid has no tails, the moment coefficients are quite different than those presented by Parikh and Chung, 23 which included the empenage. The adapted DES grid shows quite good agreement throughout the entire angle of attack range.…”

Section: Steady/time-averaged Resultsmentioning

confidence: 73%

Unsteady Computations of Abrupt Wing Stall Using Detached-Eddy Simulation

Forsythe

Woodson

2005

Journal of Aircraft

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Unsteady computational fluid dynamics calculations are presented of the abrupt wing stall phenomenon on the preproduction F/A-18E using detached-eddy simulation. Detached-eddy simulation combines the efficiency of a Reynolds-averaged turbulence model near the wall with the fidelity of large-eddy simulation in separated regions. Because it uses large-eddy simulation in the separated regions, it is capable of predicting the unsteady motions associated with separated flows. Detached-Eddy Simulation has been applied to predict the unsteady shock motion present on the F/A-18E at transonic speeds over several angles of attack. Solution-based grid adaption is used on unstructured grids to improve the resolution in the separated region. Mean flow results are compared to leading Reynolds-averaged models showing improved predictive capability. Unsteady surface pressures are shown to be in good agreement with experimental measurements. The presence of low-frequency pressure oscillations due to shock motion in the current simulations and the experiments motivated a full aircraft calculation, which showed low-frequency high-magnitude rolling moments that could be a significant contributor to the abrupt wing stall phenomenon.

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Section: Steady/time-averaged Resultsmentioning

confidence: 73%

Unsteady Computations of Abrupt Wing Stall Using Detached-Eddy Simulation

Forsythe

Woodson

2005

Journal of Aircraft

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“…Contrast the sectional lift characteristics 11 between the F-16C and the F/A-18E presented in Figure 5 for several AoA at Mach 0.9. As the AoA increases for the F-16C, the maximum wing loading moves inboard in a continuous, smooth manner, and the maximum sectional lift is achieved about mid-span at the highest AoA.…”

Section: Cfd Figures Of Merit (Fom)mentioning

confidence: 94%

“…This parameter has proven to be a reliable indicator of the onset of AWS for each of the aircraft configurations considered in this study, and provides numerous insights into where the problem occurs, both in terms of AoA and location along the wingspan. 8,10,11 Figures 6 and 7, taken from reference 10, show plots of the sectional lift coefficient and its derivative with respect to AoA for two different aircraft configurations. Figure 6 gives the results for the baseline F/A-18C and Figure 7 presents the results for the baseline F/A-18C with the addition of a LE snag of the same normalized dimensions and location as that used on the F/A-18E.…”

Section: Cfd Figures Of Merit (Fom)mentioning

confidence: 99%

Recommendations for CFD Procedures for Predicting Abrupt Wing Stall

Woodson¹,

Green²,

Chung³

et al. 2003

41st Aerospace Sciences Meeting and Exhibit

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This paper summarizes the lessons learned from the computational fluid dynamics (CFD) effort of the joint NASA/Navy/Air Force Abrupt Wing Stall (AWS) Program, discusses the results, and makes recommendations for approaches to be used in future aircraft programs to identify uncommanded lateral characteristics early in the design phase of an aircraft development program. The discussion also suggests CFD procedures and figures of merit for use in predicting and quantifying AWS tendencies and vulnerabilities of the proposed designs. Topics addressed include critical parameters that can be used to identify uncommanded lateral activity in the transonic flow regime, and the geometric parameters that were the primary contributors to the adverse lateral activity observed on pre-production F/A-18E/F aircraft. In addition, differences in steady-state and averaged time-accurate CFD solutions for the F/A-18E in the AWS region of interest are analyzed and compared with existing unsteady experimental data to determine the utility and accuracy of the unsteady approach. Lastly, proposed CFD figures of merit are critically evaluated as indicators of possible AWS tendencies, and screening procedures for the identification of AWS are suggested.

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“…Although the change in slope of the C WB curve has been shown previously to be a more reliable indicator of AWS than the slope of the lift curve, Parikh and Chung 11 have shown that the halfplane rolling-moment coefficient C l provides identical information, as illustrated in Fig. 8.…”

Section: Cfd Fommentioning

confidence: 94%

“…This parameter has proven to be a reliable indicator of the onset of AWS for each of the aircraft configurations considered in this study and provides numerous insights into where the problem occurs, both in terms of AoA and location along the wingspan. 8,10,11 Figures 6 and 7, taken from Ref. 10, show plots of the sectional lift coefficient and its derivative with respect to AoA for two different aircraft configurations.…”

Section: Cfd Fommentioning

confidence: 99%

Recommendations for Computational-Fluid-Dynamics Procedures for Predicting Abrupt Wing Stall

Woodson

Green

Chung

et al. 2005

Journal of Aircraft

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This paper summarizes the lessons learned from the computational-fluid-dynamics effort of the joint NASA/Navy/Air Force Abrupt Wing Stall Program, discusses the results, and makes recommendations for approaches to be used in future aircraft programs to identify uncommanded lateral characteristics early in the design phase of an aircraft development program. The discussion also suggests procedures and figures of merit for use in predicting and quantifying rapid and severe wing-stall tendencies and vulnerabilities of the proposed designs. Topics addressed include critical parameters that can be used to identify uncommanded lateral activity in the transonic flow regime and the geometric parameters that were the primary contributors to the adverse lateral activity observed on preproduction F/A-18E/F aircraft. In addition, differences in steady-state and averaged time-accurate computational solutions for the F/A-18E in the abrupt-wing-stall region of interest are analyzed and compared with existing unsteady experimental data to determine the utility and accuracy of the unsteady approach. Lastly, proposed computational figures of merit are critically evaluated as indicators of possible abrupt separation tendencies, and screening procedures for the identification of those tendencies are suggested.

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Computational Study of the Abrupt-Wing-Stall Characteristics of F/A-18E and F-16C

Cited by 5 publications

References 9 publications

Unsteady Computations of Abrupt Wing Stall Using Detached-Eddy Simulation

Unsteady Computations of Abrupt Wing Stall Using Detached-Eddy Simulation

Recommendations for CFD Procedures for Predicting Abrupt Wing Stall

Recommendations for Computational-Fluid-Dynamics Procedures for Predicting Abrupt Wing Stall

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