Abstract
Concerns about the noise generated by the structure of aircraft have significantly
increased over the past years due to reductions in the engine noise and tighter
regulations established by certifying entities. Slat is one of the most important
sources of airframe noise, since it generates a noise spectrum composed of midfrequency tones, a broadband component, and a high-frequency hump. This article addresses a detailed analysis of the high-frequency tone generation and its relation to the slat trailing-edge thickness. Numerical simulations of a typical three-element airfoil were conducted by PowerFLOW 5.3 software at 1 million Reynolds number and the noise was propagated according to the Ffowcs William-Hawking methodology. The high spatial and temporal resolution in the simulations aimed to capture variations in the slat trailing-edge thickness. The results showed the presence of a strong vortex shedding behind the slat, which is highly related to the high-frequency tone and the blunt slat trailing-edge. The frequency of the tone in the far-field spectrum is in agreement with that in the vortex shedding. The Strouhal number calculated with the use of the boundary layer displacement thickness as the characteristic length was constant for all cases and close to 0.4.
increased over the past years due to reductions in the engine noise and tighter
regulations established by certifying entities. Slat is one of the most important
sources of airframe noise, since it generates a noise spectrum composed of midfrequency tones, a broadband component, and a high-frequency hump. This article addresses a detailed analysis of the high-frequency tone generation and its relation to the slat trailing-edge thickness. Numerical simulations of a typical three-element airfoil were conducted by PowerFLOW 5.3 software at 1 million Reynolds number and the noise was propagated according to the Ffowcs William-Hawking methodology. The high spatial and temporal resolution in the simulations aimed to capture variations in the slat trailing-edge thickness. The results showed the presence of a strong vortex shedding behind the slat, which is highly related to the high-frequency tone and the blunt slat trailing-edge. The frequency of the tone in the far-field spectrum is in agreement with that in the vortex shedding. The Strouhal number calculated with the use of the boundary layer displacement thickness as the characteristic length was constant for all cases and close to 0.4.
| Original language | English |
|---|---|
| Title of host publication | Internoise: noise control for a better environment |
| Publication status | Published - 2019 |
| Externally published | Yes |
| Event | 48th International Congress and Exhibition on Noise Control Engineering, INTERNOISE 2019 - Madrid, Spain Duration: 16 Jun 2019 → 19 Jun 2019 Conference number: 48 |
Conference
| Conference | 48th International Congress and Exhibition on Noise Control Engineering, INTERNOISE 2019 |
|---|---|
| Abbreviated title | INTERNOISE 2019 |
| Country | Spain |
| City | Madrid |
| Period | 16/06/19 → 19/06/19 |