Aerodynamic characteristics of NACA 4412 airfoil section with flap in extreme ground effect

Ockfen, Alex E.; Matveev, Konstantin I.

doi:10.2478/ijnaoe-2013-0001

Cited by 33 publications

(11 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The findings of morphing the airfoil in the ground effect are shown to agree with those of Ockfen and Matveev (2009), who tested an airfoil with a trailing-edge flap in the ground effect.…”

Section: Effects Of Morphing Trailing-edge Deflectionsupporting

confidence: 77%

Aerodynamic Performance of Morphing and Periodic Trailing-Edge Morphing Airfoils in Ground Effect

Clements

Djidjeli

2023

J. Aerosp. Eng.

View full text Add to dashboard Cite

Applying fish bone active camber morphing to the wing-in-ground effect to improve the aerodynamic efficiency was investigated 6 using computational fluid dynamics (CFD) at a Reynolds number of 320,000. Steady-static morphing was first carried out with Reynolds-7 averaged Navier-Stokes (RANS) equations in two dimensions for morphing start locations off (60%, 80%, and 90% chord), ground clear-8 ances (h=c ¼ 0.1, 0.2, 0.4, 1), and angles of attack (AoAs) 0°, 2°, 3°, 4°, and 12°. A morphing displacement (w te ) of 0.5% increased the 9 efficiency by 2.8% (compared to non-morphing in the ground effect) for the 3°AoA and 90% start location, and by 62% in comparison to the baseline unmorphed airfoil in freestream. Reducing h=c ¼ 1 to 0.1 increased the lift between 10% and 17%; the larger gain was with the highest morphing deflection. A key finding was that morphing the airfoil reduced the distance between the trailing edge and ground, enhancing the ground effect. Also, morphing at an earlier start location in the chord direction resulted in a smaller area beneath the airfoil, reducing the total pressure, which reduced the overall lift compared to a later morphing start location. Dynamic morphing at 1 Hz using URANS K-Omega-SST showed a similar amount of lift as static morphing but a slightly higher amount of drag. Reducing the period caused an initial overshoot in drag before settling. The dynamic ground effect showed higher efficiency at low AoAs compared to dynamic morphing in freestream, which is beneficial for aircraft to fly with less pitch. Finally, periodic morphing for h=c ¼ 0.1 using sinusoidal motion with morphing starting at 25% along the chord and 4°AoA was investigated between 0.05% to 0.15% w te and 0.5 to 3.5 Strouhal number.Periodically morphing at 0.125% w te and Strouhal number of 0.9 using DES simulations increased the efficiency by 5.4%; however, it reduced the lift by 0.7%, the drag reduced by 5.8%, and it showed Kelvin-Helmholtz instability at 9.8 Strouhal number.

show abstract

“…The findings of morphing the airfoil in the ground effect are shown to agree with those of Ockfen and Matveev (2009), who tested an airfoil with a trailing-edge flap in the ground effect.…”

Section: Effects Of Morphing Trailing-edge Deflectionsupporting

confidence: 77%

Aerodynamic Performance of Morphing and Periodic Trailing-Edge Morphing Airfoils in Ground Effect

Clements

Djidjeli

2023

J. Aerosp. Eng.

View full text Add to dashboard Cite

show abstract

“…This applies to both airfoils with a small relative thickness [72,73] and thick profiles [71]. Moreover, this also applies to airfoils operating at low Reynolds number regimes [72] as well as high ones, similar to those analyzed in this paper [71,73,74]. Therefore, in this work the domain shown in Figure 1b was used, in which the distance between the airfoil and the edge of the domain is 20 c. Moreover, by comparing the results of the aerodynamic force coefficients obtained with the ANSYS Fluent code with the results obtained with the FLOWer code, where the domain size L/c is 100, no significant differences were noticed.…”

Section: Computational Domain Mesh and Boundary Conditionssupporting

confidence: 61%

Accuracy of the Gamma Re-Theta Transition Model for Simulating the DU-91-W2-250 Airfoil at High Reynolds Numbers

et al. 2021

View full text Add to dashboard Cite

Accurate computation of the performance of a horizontal-axis wind turbine (HAWT) using Blade Element Momentum (BEM) based codes requires good quality aerodynamic characteristics of airfoils. This paper shows a numerical investigation of transitional flow over the DU 91-W2-250 airfoil with chord-based Reynolds number ranging from 3 × 106 to 6 × 106. The primary goal of the present paper is to validate the unsteady Reynolds averaged Navier-Stokes (URANS) approach together with the four-equation transition SST turbulence model with experimental data from a wind tunnel. The main computational fluid dynamics (CFD) code used in this work was ANSYS Fluent. For comparison, two more CFD codes with the Transition SST model were used: FLOWer and STAR-CCM +. The obtained airfoil characteristics were also compared with the results of fully turbulent models published in other works. The XFOIL approach was also used in this work for comparison. The aerodynamic force coefficients obtained with the Transition SST model implemented in different CFD codes do not differ significantly from each other despite the different mesh distributions used. The drag coefficients obtained with fully turbulent models are too high. With the lowest Reynolds numbers analyzed in this work, the error in estimating the location of the transition was significant. This error decreases as the Reynolds number increases. The applicability of the uncalibrated transition SST approach for a two-dimensional thick airfoil is up to the critical angle of attack.

show abstract

“…Moreover, the occurrence of flow separation over the upper surface also contributes to the overall larger drag. Ockfen and Matveev [12] found that a small flap deflection (h f /c = 0.025) yielded the largest increase in the L/D ratio. In the case of flap deflections larger than (h f /c = 0.05), the aerodynamic efficiency was reduced due to the relative increase in the pressure drag compared to the additional aerodynamic lift.…”

Section: Chord-dominated Effectsmentioning

confidence: 98%

“…Since the key factor for the WIG effect appears to be predominantly caused by an increase in the pressure underneath the wing, research has been conducted to further enhance the lower-side pressure. Ockfen and Matveev [12] investigated the use of a trailing edge flap to enhance lift generation. Utilizing a numerical study involving RANS, the use of either a split flap or a plain flap was investigated.…”

Section: Chord-dominated Effectsmentioning

confidence: 99%

Experimental and Numerical Analyses of a Novel Wing-In-Ground Vehicle

et al. 2022

View full text Add to dashboard Cite

The AeroCity is a new form of transportation concept that has been developed to provide high-speed ground transportation at a much lower cost than the existing high-speed railway. Utilizing the Wing-in-Ground (WIG) effect, the AeroCity vehicle does not require complex infrastructures like other contemporary concepts, such as the Hyperloop or Maglev trains. In the current work, the aerodynamic characteristics of the AeroCity vehicle are examined through a Computational Fluid Dynamics (CFD) analysis. The results from the CFD analysis qualitatively match with the findings of wind tunnel experiments. Surface streamlines and boundary layer measurements correspond well with the numerical data. However, the force measurements show a discrepancy. It is found that the separation bubble over the side plates is not captured by the CFD, and this is responsible for an under-prediction of the drag at higher free-stream velocities. The Transition SST model improved the matching between the experiments and numerical simulations. The influence of the moving ground is numerically investigated, and the effect of non-moving ground on the vehicle aerodynamics was found not to be significant. Finally, the inclusion of the track wall is examined. It is found that the merging of the wingtip vortices is responsible for a significant drag increase and, therefore, an alternative track geometry should be investigated.

show abstract

Aerodynamic characteristics of NACA 4412 airfoil section with flap in extreme ground effect

Cited by 33 publications

References 13 publications

Aerodynamic Performance of Morphing and Periodic Trailing-Edge Morphing Airfoils in Ground Effect

Aerodynamic Performance of Morphing and Periodic Trailing-Edge Morphing Airfoils in Ground Effect

Accuracy of the Gamma Re-Theta Transition Model for Simulating the DU-91-W2-250 Airfoil at High Reynolds Numbers

Experimental and Numerical Analyses of a Novel Wing-In-Ground Vehicle

Contact Info

Product

Resources

About