1. Field
The present disclosure relates generally to an apparatus for acquiring data and a method for selecting subsets of the acquired data. Still more particularly, the present disclosure relates to an apparatus for acquiring data and a method for selecting data for use in identifying noise sources.
2. Background
The analysis of noise and the sources or causes of noise is often performed to understand the physics behind the noise generation. For example, an analysis may be performed to identify where the noise is coming from. This type of analysis may be performed in the testing of devices. For example, noise data may be collected for an aircraft engine, such as a jet engine. The noise data collected may be analyzed to determine what components within, and exterior to the jet engine contribute to the noise. These different components may also be referred to as a component noise sources.
Different structures or components in a jet engine or in the jet exhaust generated by a jet engine may contribute different noises at different frequencies. For example, different surfaces within ducts and inlets of a jet engine may contribute noise during the operation of the jet engine. For example, the high speed exhaust flow may contribute noise during the operation of the engine.
For example, surfaces may be treated with various compounds or components in an effort to reduce noise. With this type of example, the jet engine may be tested with the different types of surfaces to determine whether a noise contribution from those surfaces is reduced with the different treatments.
Currently, arrays of microphones may be used to collect noise data. This noise data may be processed to produce a “picture” of where the noise is coming from, and to determine the intensity of the radiated noise. In obtaining this data, microphones may be placed at different locations. With current array designs, hundreds or thousands of array locations are needed to cover all the sound propagation paths formed by connecting hundreds of candidate noise source locations to dozens of measurement points of interest.
The currently used methods for obtaining noise using arrays of microphones are limited to the array size or location. Further, the current methodologies may collect noise information with limited numbers of microphones. The microphones are placed down on a location from which noise data is to be collected. This type of collection may result only in noise data being collected for a limited number of emission angles.
Therefore, it would be advantageous to have a method and apparatus that overcomes the problems described above.