# The Effects of a Morphed Trailing-Edge Flap on the Aeroacoustic and Aerodynamic Performance of a 30P30N Aerofoil

^{*}

## Abstract

**:**

_{l}/C

_{d}ratio compared with the conventional flap. The methodology reported here for the 30P30N is a quick tool for initial estimates of the far-field noise and aerodynamic performance of a morphing flap at the design stage.

## 1. Introduction

## 2. Materials and Methods

#### 2.1. Governing Equations and Numerical Schemes

#### 2.2. Geometry and Computational Domain

#### 2.3. Mesh

#### 2.4. Solver Method

^{−5}s) was chosen to achieve a Courant number of ~1. There were 10 inner iterations per timestep. A Courant number of 1 was used (refer to Timestep Study, Section 2.5), flow velocity was 30 m/s, and ∆x was the smallest mesh element size in the flow-wise direction; this gives $\Delta t=1.07\times {10}^{-5}$ seconds.

#### 2.5. Timestep Study

## 3. Results and Discussion

#### 3.1. Validation

#### 3.2. Results of Morphed and Conventional Flap Design

_{l}/C

_{d}ratio, see Table 2), compared with a higher C

_{l}/C

_{d}ratio for the conventional reference design (see Table 1).

## 4. Conclusions and Future Work

## Author Contributions

## Funding

## Acknowledgments

## Conflicts of Interest

## References

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**Figure 3.**CML flap design (CML circled in blue): wind tunnel model from (

**a**) pressure side and (

**b**) suction side (Streett et al. [6]).

**Figure 6.**Representation of CFL condition and Courant number (C), and their effects on timestep across grid spacing (each red square is the next data point).

**Figure 8.**SPL vs. frequency plot of varying CFL numbers. Tonal peaks at 4.5 kHz and 9 kHz only detectable with C = 0.7 and C = 1.

**Figure 9.**Pressure coefficient plots of numerical data against experimental data for the 30P30N aerofoil, from the work of Murayama et al. (2014) [3]: (

**a**) 3° AoA; (

**b**) 8° AoA.

**Figure 10.**Lift coefficient vs. angle of attack comparison of current numerical data with the experimental and numerical data of Murayama et al. [3].

**Figure 11.**SPL vs. Strouhal number comparison of numerical data with the experimental data of Jawahar et al. [4].

**Figure 12.**SPL vs. frequency at an 8° AoA for conventional and morphed flap designs across all flap deflections tested: (

**a**) 5° flap deflection; (

**b**) 10° flap deflection; (

**c**) 15° flap deflection; (

**d**) 20° flap deflection; (

**e**) 25° flap deflection.

**Figure 15.**3rd octave band plot for morphed and conventional flap configurations, where a mean value is made for each frequency band, representing all flap deflections in one plot.

**Figure 16.**Turbulent kinetic energy (TKE) plot at 5° flap deflection: (

**a**) conventional design; (

**b**) morphed design.

**Figure 17.**Static pressure contour plots at 20° flap deflection for: (

**a**) conventional configuration; (

**b**) morphed configuration.

**Figure 18.**Plots of velocity magnitude on streamlines around the trailing edge region at 20° flap deflection: (

**a**) conventional configuration; (

**b**) morphed configuration.

Flap Deflection (°) | ${\mathit{C}}_{\mathit{l}}$ | ${\mathit{C}}_{\mathit{d}}$ | ${\mathit{C}}_{\mathit{l}}$$/{\mathit{C}}_{\mathit{d}}$ |
---|---|---|---|

5 | 1.24 | 0.0758 | 16.37 |

10 | 1.51 | 0.0873 | 17.34 |

15 | 1.8 | 0.114 | 15.81 |

20 | 2.02 | 0.127 | 15.95 |

25 | 1.91 | 0.139 | 13.77 |

Flap Deflection (°) | ${\mathit{C}}_{\mathit{l}}$ | ${\mathit{C}}_{\mathit{d}}$ | ${\mathit{C}}_{\mathit{l}}$$/{\mathit{C}}_{\mathit{d}}$ |
---|---|---|---|

5 | 1.33 | 0.0734 | 18.08 |

10 | 1.66 | 0.0919 | 18.05 |

15 | 1.69 | 0.110 | 15.41 |

20 | 1.94 | 0.146 | 13.25 |

25 | 2.06 | 0.182 | 11.30 |

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**MDPI and ACS Style**

Watkins, J.; Bouferrouk, A. The Effects of a Morphed Trailing-Edge Flap on the Aeroacoustic and Aerodynamic Performance of a 30P30N Aerofoil. *Acoustics* **2022**, *4*, 248-267.
https://doi.org/10.3390/acoustics4010015

**AMA Style**

Watkins J, Bouferrouk A. The Effects of a Morphed Trailing-Edge Flap on the Aeroacoustic and Aerodynamic Performance of a 30P30N Aerofoil. *Acoustics*. 2022; 4(1):248-267.
https://doi.org/10.3390/acoustics4010015

**Chicago/Turabian Style**

Watkins, Joseph, and Abdessalem Bouferrouk. 2022. "The Effects of a Morphed Trailing-Edge Flap on the Aeroacoustic and Aerodynamic Performance of a 30P30N Aerofoil" *Acoustics* 4, no. 1: 248-267.
https://doi.org/10.3390/acoustics4010015