An Acoustics Intensity Based Investigation οf the Energy Flow Over the Barriers

Szczodrak

et al. 2017

Archives of Acoustics

The aim of the paper was to compare acoustic field around the open and stopped organ pipes. The wooden organ pipe was located in the anechoic chamber and activated with a constant air flow, produced by an external air-compressor. Thus, a long-term steady state response was possible to obtain. Multichannel acoustic vector sensor was used to measure the sound intensity distribution of radiated acoustic energy. Measurements have been carried out on a defined fixed grid of points. A specialized Cartesian robot allowed for a precise positioning of the acoustic probe. The resulted data were processed in order to obtain and visualize the sound intensity distribution around the pipe, taking into account the type of the organ pipe, frequency of the generated sound, the sound pressure level and the direction of acoustic energy propagation. For the open pipe, an additional sound source was identified at the top of the pipe. In this case, the streamlines in front of the pipe are propagated horizontally and in a greater distance than in a case of the stopped pipe, moreover they are directed downwards. For the stopped pipe, the streamlines of the acoustic flow were directed upwards. The results for both pipe types were compared and discussed in the paper.

Section: Introductionmentioning

confidence: 99%

Sound Intensity Distribution Around Organ Pipe

Odya

Szczodrak

et al. 2017

Archives of Acoustics

“…Typically, intensity metric quantities are used for measuring energy transmission and propagation paths (Weyna, 2003;2010), as well as for detection of noise source localization (Kotus, 2015), determination of acoustic impedance and reflection index of materials (De Bree, 2003;Weyna, 2003), although one may find several examples of employing them in audio engineering Woszczyk et al, 2007), and in particular in the recording and reconstruction of the acoustic field, e.g. ambisonics ).…”

Section: Introductionmentioning

confidence: 99%

3D Acoustic Field Intensity Probe Design and Measurements

Czyżewski

Kostek

2016

Archives of Acoustics

The aim of this paper is two-fold. First, some basic notions on acoustic field intensity and its measurement are shortly recalled. Then, the equipment and the measurement procedure used in the sound intensity in the performed research study are described. The second goal is to present details of the design of the engineered 3D intensity probe, as well as the algorithms developed and applied for that purpose. Results of the intensity probe measurements along with the calibration procedure are then contained and discussed. Comparison between the engineered and the reference commercial probe confirms that the designed construction is applicable to the sound field intensity measurements with a sufficient effectiveness.

“…The visualization of acoustic energy flow in real acoustic 3D space fields can explain many of energetic effects (scattering, vortex flow, shielding area, etc.) [7].…”

Section: Introductionmentioning

confidence: 99%

A System for Acoustic Field Measurement Employing Cartesian Robot

Szczodrak

Kurowski

Metrology and Measurement Systems

et al. 2016

A system setup for measurements of acoustic field, together with the results of 3D visualisations of acoustic energy flow are presented in the paper. Spatial sampling of the field is performed by a Cartesian robot. Automatization of the measurement process is achieved with the use of a specialized control system. The method is based on measuring the sound pressure (scalar) and particle velocity(vector) quantities. The aim of the system is to collect data with a high precision and repeatability. The system is employed for measurements of acoustic energy flow in the proximity of an artificial head in an anechoic chamber. In the measurement setup an algorithm for generation of the probe movement path is included. The algorithm finds the optimum path of the robot movement, taking into account a given 3D object shape present in the measurement space. The results are presented for two cases, first without any obstacle and the other − with an artificial head in the sound field.