Abstract: For the aeroacoustic wind test, a common case is that not all parameters can be simulated sometimes (e.g., model size, Mach number and Reynolds number and so on). Correspondingly, the test results transformation based on similarity laws is needed. Based on the 5.5m×4m aeroacoustic wind tunnel and full model and half model for the aeroacoustic study of large-scale aircraft, the properties and similarity laws of high-lift device noise were studied experimentally. During the study of similarity laws, the correction of frequency and amplitude of noise spectrum was considered mainly. The transformation methods based on St number and He number are compared for frequency correction. The amplitude correction parameters are considered as different values in divided frequency ranges based on the study, and the guidance for the selection of division frequency. Further, the uniformity of the two frequency transformation methods is analysed. The results indicate that, the sound source composition, mechanism and principles for high-lift device noise are different in various frequency range, and are affected by slat/flap angles, angle of attack of model, wind speed, test position/propagation direction and so on. A good similarity is presented for the high-lift device noise on the whole. Based on the similarity transformation method, the noise at different wind speeds is predicted effectively, and the prediction method is well suitable for various model situations and test positions. The slope of noise spectrum is related to sound source composition and properties, and the break frequency of the slope can be selected as the dividing frequency for the frequency ranges. For the model states with non-zero angle of attack, when the frequency correction is based on He number, a good prediction results can be obtained with the amplitude correction parameters setting as 5 and 6, respectively, in middle to low frequency range and middle to high frequency range. To some extent, the transformation method based on St number and He number has inherent unity.

Key words: high-lift device, aerodynamic noise, wind tunnel test, similarity law, frequency correction, amplitude correction