The Characteristic of Sound Reflections from Curved Reflective Panels

Abstract

The paper presents the verification of a solution to the narrow sound frequency range problem of flat reflective panels. The analytical, numerical and experimental studies concerned flat panels, panels with curved edges and also semicircular elements. There were compared the characteristics of sound reflected from the studied elements in order to verify which panel will provide effective sound reflection and also scattering in the required band of higher frequencies, i.e. above the upper limit frequency. Based on the conducted analyzes, it was found that among some presented solutions to narrow sound frequency range problem, the array composed of panels with curved edges is the most preferred one. Nevertheless, its reflection characteristic does not meet all of the requirements, therefore, it is necessary to search for another solution of canopy which is effective over a wide frequency range.

Investigation into the Acoustic Properties of Polylactic Acid Sound-Absorbing Panels Manufactured by 3D Printing Technology: The Influence of Nozzle Diameters and Internal Configurations

“…The study in [29] of the natural behavior of infinite uniform layers of a porous material considered the relationship between pressure and velocity, and the results focused on the evaluation of the intrinsic properties of the material based on the acoustic surface impedance of plane waves using two parameters: the energy deviation index and the real reflection angle. Sound reflection is the phenomenon of a sound returning to the medium from which it originates when it meets the separation surface with another medium, which has a different density [30,31].…”

Effect of 3D-Printed PLA Structure on Sound Reflection Properties

“…Sound propagates through the air or other media as a longitudinal wave, in which the mechanical vibrations run in the direction of wave propagation. The property of waves and sound associated with the echo phenomenon is known as reflection [ 7 , 8 , 9 , 10 ].…”

Sound Scattering by Gothic Piers and Columns of the Cathédrale Notre-Dame de Paris

“…Examples of modern applications are the canopy of reflectors suspended above some concert hall stages [2] or hanging panels in reverberation chambers [3]. As they are finite-sized objects, they usually have less effect on long wavelengths [4], and the effect of the curvature of reflector panels on this frequency limit has been considered [5,6]. For wavelengths of comparable size, the waves can propagate around the obstacle and are strongly diffracted, notably in the shadow zone [7].…”

“…Subsequently, analytical solutions using partial wave series expansion methods have been derived for simple shapes [17,18]. The study of more arbitrary geometries involving complex shapes and/or multiples bodies can be achieved using measurements on full-size [5] or scale models [19] and simulations with appropriate computational methods. Frequency methods solving the Helmholtz equation, such as the boundary element method [20,21] or the finite element method [22] have been employed.…”