# Effect of Chordwise Struts and Misaligned Flow on the Aerodynamic Performance of a Leading-Edge Inflatable Wing

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## Abstract

**:**

## 1. Introduction

## 2. Methodology

#### 2.1. Geometric Model of the Wing

#### 2.2. Meshing of the Wing Geometry

#### 2.3. Fluid Dynamic Solver

## 3. Results

#### 3.1. Aerodynamics without Side-Slip

#### 3.2. Aerodynamics with Side-Slip

## 4. Conclusions

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Acknowledgments

## Conflicts of Interest

## References

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**Figure 1.**TU Delft V3A kite with 25 ${\mathrm{m}}^{2}$ wing surface area: (

**a**) during flight and (

**b**) design geometry with body-fixed reference frame ($X,Y,Z$) and definition of the side-slip angle $\beta $ and angle of attack $\alpha $ to describe the direction of the undisturbed inflow velocity ${\mathbf{U}}_{\infty}$ relative to the wing.

**Figure 2.**Smoothing the attachment of strut tubes and canopy: wing geometry before (

**left**) and after (

**right**) the filleting. In the original CAD geometry the strut tubes are attached to the leading edge tube. Because the connection of the leading edge tube with the canopy is also smoothed by a fillet [20], the strut tubes connect to this fillet surface and not anymore to the original leading edge tube.

**Figure 3.**Closure of the open tube geometry: original CAD model on the (

**left**) and closed geometry on the (

**right**).

**Figure 6.**Contour plot of the pressure coefficient ${C}_{p}$ on the wing surface and streamlines around the tip regions coloured by the transverse velocity component ${U}_{z}$ for $\mathrm{Re}=3\times {10}^{6}$, $\alpha ={12}^{\circ}$ and $\beta ={0}^{\circ}$, taken from [23].

**Figure 7.**Contour plots of streamwise skin friction coefficient ${C}_{f,x}$ on the surface and total pressure coefficient ${C}_{p,T}$ in the symmetry plane ($Z=0$) for $\mathrm{Re}=3\times {10}^{6}$ and $\beta =0$, taken from [23].

**Figure 8.**Streamlines and magnitude of the velocity field in the wing symmetry plane ($Z=0$) for $\alpha ={6}^{\circ}$, taken from [23]: (

**a**) $\mathrm{Re}={10}^{5}$ and (

**b**) $\mathrm{Re}=3\times {10}^{6}$.

**Figure 9.**Contour plot of the streamwise component of the friction coefficient on the pressure side of the wing, for $\mathrm{Re}=3\times {10}^{6}$ and $\alpha ={12}^{\circ}$, taken from [23].

**Figure 10.**${\lambda}_{2}$-criterion for $\mathrm{Re}=3\times {10}^{6}$ and $\alpha ={12}^{\circ}$ in slices perpendicular to the incoming flow, taken from [23].

**Figure 11.**Aerodynamic force coefficients as functions of the angle of attack, without side-slip: (

**a**) lift coefficient ${C}_{L}$ and (

**b**) drag coefficient ${C}_{D}$.

**Figure 13.**Chordwise ${C}_{P}$ distribution at the symmetry plane for $\mathrm{Re}={10}^{5}$ and $\alpha ={6}^{\circ}$.

**Figure 14.**Chordwise ${C}_{f,x}$ distribution at the symmetry plane for $\mathrm{Re}={10}^{5}$ and $\alpha ={6}^{\circ}$.

**Figure 15.**Pressure coefficient ${C}_{P}$ (colouring of wing surface) and transverse component ${U}_{z}$ of the flow velocity (colouring of an $YZ$-plane in the wake flow) for $\mathrm{Re}=3\times {10}^{6}$ and $\alpha ={12}^{\circ}$, taken from [23].

**Figure 17.**Side force coefficient as a function of the side-slip angle for $\alpha ={12}^{\circ}$, taken from [23].

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**MDPI and ACS Style**

Viré, A.; Lebesque, G.; Folkersma, M.; Schmehl, R. Effect of Chordwise Struts and Misaligned Flow on the Aerodynamic Performance of a Leading-Edge Inflatable Wing. *Energies* **2022**, *15*, 1450.
https://doi.org/10.3390/en15041450

**AMA Style**

Viré A, Lebesque G, Folkersma M, Schmehl R. Effect of Chordwise Struts and Misaligned Flow on the Aerodynamic Performance of a Leading-Edge Inflatable Wing. *Energies*. 2022; 15(4):1450.
https://doi.org/10.3390/en15041450

**Chicago/Turabian Style**

Viré, Axelle, Geert Lebesque, Mikko Folkersma, and Roland Schmehl. 2022. "Effect of Chordwise Struts and Misaligned Flow on the Aerodynamic Performance of a Leading-Edge Inflatable Wing" *Energies* 15, no. 4: 1450.
https://doi.org/10.3390/en15041450