@article {LI:2024:0736-2935:7873, title = "The mitigation of airframe noise using a Krueger flap as a leading-edge device in a high-lift configuration", journal = "INTER-NOISE and NOISE-CON Congress and Conference Proceedings", parent_itemid = "infobike://ince/incecp", publishercode ="ince", year = "2024", volume = "270", number = "4", publication date ="2024-10-04T00:00:00", pages = "7873-7882", itemtype = "ARTICLE", issn = "0736-2935", url = "https://ince.publisher.ingentaconnect.com/content/ince/incecp/2024/00000270/00000004/art00097", doi = "doi:10.3397/IN_2024_4017", author = "LI, Shuai and DAVIDSON, Lars and PENG, Shia-Hui and POTT-POLLENSKE, Michael", abstract = "High-lift device is a potent airframe noise contributor. The conventional slat, commonly used in a high-lift device, is known as one of the dominant noise sources. Here, we combine an experimental and a numerical approach to investigate the noise generation of a conventional slat and two Krueger flaps as leading-edge devices in a high-lift configuration. To reduce the computational cost, a short span of the entire high-lift device is selected as the focusing region for scale-resolving and acoustic computations using Improved Delayed Detached Eddy Simulation (IDDES) coupled with the Ffowcs-Williams and Hawkings (FWH) analogy. Simulation results show that turbulent cross flows induce slightly lower-level noise spectra at frequencies less than 300 Hz when the two spanwise sides of the FWH permeable integral surface are closed. Wind-tunnel test results show that the reference and optimal Krueger configurations effectively attenuate the dominant tone of the conventional slat by 4 and 6 dB, respectively. Besides, the optimal configuration is very effective in noise reduction in a wide frequency range. However, the reference Krueger configuration increases the noise level by 0 4 dB at frequencies exceeding 5, 500 Hz. Overall, the optimal Krueger configuration is a good choice for high-lift device noise mitigation.", }