Bence Tóth

Budapest University of Technology and Economics · Department of Fluid Mechanics

In the present paper, the fuzzy c-means method is extended, and an algorithm is proposed for fuzzy clustering of data lying in a feature space of arbitrary dimensions, with one of them being periodic. To aid in determining the optimal number of clusters, the Xie-Beni validity index is extended, to account for the periodicity. Furthermore, the relat...

The aim of this paper is to present two acoustic beamforming methods developed for rotating sources, namely the Rotating Source Identifier (ROSI) and the Virtual Rotating Array method (VRAM). These were applied onto a series of simulated test cases, and their behaviour was analysed. Both methods were able to localise the source reliably. However, t...

An objective and algorithmised methodology is proposed to analyse beamform data obtained for axial fans. Its application is demonstrated in a case study regarding the tip region of a low-speed cooling fan. First, beamforming is carried out in a co-rotating frame of reference. Then, a distribution of source strength is extracted along the circumfere...

Axial fans operate in large numbers, often in the close vicinity of humans, therefore reducing their noise is a primary concern. In this paper, beamforming is applied to get information about the location and strength of noise sources on the rotor. This information is invaluable, however, difficult to interpret because of some limitations of the be...

In order to establish guidelines for reducing the noise emitted by an axial flow fan, the case study-specific dominant noise sources are to be characterized. Beamforming based on a Phased Array Microphone (PAM) system offers a powerful diagnostics tool for such purpose. In general, the evaluation of the beamforming maps involves certain subjective...

Using classical beamforming methods for localizing unducted tonal turbomachinery noise sources leads to coherent tonal noise sources being localized to their Mach radii rather than their true noise source locations. For certain configurations, the interaction tone noise sources will be localized to a Mach radius of zero. In such instances, the cont...

Beamforming processes developed specifically for rotating sources have provided a nonintrusive means by which turbomachinery noise sources can be localized. Investigations by Horváth et al. have shown that for unducted rotating coherent noise sources beamforming will localize the noise sources to their Mach radii rather than their true noise source...

The aim of this paper is to illustrate the difficulties that arise during the evaluation of phased array microphone measurements on ducted fans in an industrial environment, and draw attention to them. A case study was carried out, and the results were processed resulting in beamforming maps, but their interpretation is not straightforward. Firstly...

Abstract Beamforming investigations focusing on the dominant noise sources of turbomachinery have become very common. As legislations and regulations have become more stringent along with the expectations of the customers, the amount of research in the field of turbomachinery aeroacoustics has progressively increased. Beamforming processes develop...