Year: 2022
Type: article
Abstract: Roughness trips are widely applied in wind-tunnel testing to hasten the laminar–turbulent boundary-layer transition. It is well known that they influence the boundary-layer transition and its development. However, their influence on aeroacoustic quantities (in particular, on the airfoil trailing-edge noise) is not yet fully understood. This paper discusses the relationship between the trip height and the boundary-layer development and radiated trailing-edge noise. Wind-tunnel experiments were performed with zigzag strips and grit elements placed on the surface of a NACA 0012 airfoil. The roughness trip heights ranged from 17 to 214% of the undisturbed boundary-layer thickness at the trip location. The chord-based Reynolds number varied from to . This paper shows that trip heights within 50 to 105% of have little influence on the near field and the trailing-edge noise. However, trips with increase the spectra of velocity and pressure fluctuations in the low-frequency range up to 2.5 and 3 dB, respectively, resulting in an increase of the trailing-edge radiated noise up to 4 dB in a similar frequency range. In summary, this paper shows the importance of carefully defining the roughness trip used to trigger a laminar–turbulent transition in aeroacoustic and aerodynamic measurements.
Source: AIAA Journal
DOI: 10.2514/1.j061570
Institution: University of Twente
Language: English
Subfield: Aerospace Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4282931655