Andrzej Kulowski | Gdansk University of Technology (original) (raw)

Uploads

Papers by Andrzej Kulowski

Buildings, Feb 4, 2024

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Social Science Research Network, 2022

Research Square (Research Square), Jan 3, 2022

After introducing Leonardo da Vinci's (LdV) predecessors in the field of light propagation resear... more After introducing Leonardo da Vinci's (LdV) predecessors in the field of light propagation research, his drawings on the topic of focussing light through a spherical mirror are analysed. The discovery of LdV is presented, according to which, at an infinitely distant source of rays, a small fragment of the canopy is enough to generate a focus, while the rest of the mirror forms caustics for which LdV did not indicate an application. An analytical description of the energy concentration in the focus and on the caustics is given, together with its reference to the geometric representation of the acoustic field in rooms. Using symmetry in the description of energy relations in acoustics and electromagnetism, the interference that occurs on the caustics produced by the acoustic and electromagnetic wave is discussed. It is explained why in the sound field in existing halls, instead of a whole caustic only its cusp is observed, which is perceived as a point-like sound focus. The size of the mirror aperture, shown graphically by LdV, is determined. How the development of receiving techniques increased the mirror aperture compared to the LdV estimate is also shown. The implementation of these improvements is presented via the example of the Arecibo and FAST radio telescopes.

Archives of Acoustics, 2016

Historic interiors with large cubature, such as reception, theatrical, and concert halls, need to... more Historic interiors with large cubature, such as reception, theatrical, and concert halls, need to be renovated periodically if they are to be preserved as cultural heritage for future generations. In such cases it is necessary to maintain appropriate balance between requirements imposed by heritage conservation authorities office which are usually being given a higher priority, applicable safety regulations, and the comfort of use, including good acoustics.The paper is a presentation of architectural interference in three historic interiors with large cubature leading to changes in their acoustic qualities. In two cases, the changes were beneficial to the functional qualities of the halls to satisfaction of the investors carrying out the renovation work. In the third instance, the architectural interference aimed at showing off the monumental valor of the interior resulted in significant degradation of its acoustics. To remedy the situation impairing the functional program of the fa...

Heritage Science

After introducing Leonardo da Vinci’s (LdV) predecessors in the field of light propagation resear... more After introducing Leonardo da Vinci’s (LdV) predecessors in the field of light propagation research, his drawings on the topic of reflecting light by a spherical mirror are analysed. The discovery of LdV is presented, according to which, at an infinitely distant source of rays, a small fragment of the canopy is enough to generate a focus, while the rest of the mirror forms a caustic for which LdV did not indicate an application. An analytical description of the energy concentration in the focus and on the caustic is given, together with its reference to the geometric representation of the acoustic field in rooms. Based on the general principles of wave motion, symmetry is shown in the description of energy relations in acoustics and electromagnetism. It is explained why in the sound field in existing halls, instead of a whole caustic only its cusp is observed, which is perceived as a point-like sound focus. The size of the mirror aperture, shown graphically by LdV, is determined. Ho...

Buildings, 2021

This paper describes the relationship between a strong architectural vision that is difficult to ... more This paper describes the relationship between a strong architectural vision that is difficult to balance, and user expectations in terms of acoustics. The focus is on the use of corten steel as the dominant finishing material on façades and interiors to achieve an expressive, symbolic message through program-based design. The architectural premises justifying the adopted solutions are presented, especially the universality and homogeneity of the material. Against this background, the influence of corten steel on the acoustics of the two largest rooms of the European Solidarity Center, which are the winter garden and the multi-purpose hall, was discussed. Remedial steps have been taken to reduce the greatest acoustic inconveniences resulting from the widespread use of metal sheet as a finishing material in rooms, i.e., excessive reverberation and a low degree of sound dispersion. A positive result for the acoustic conditions achieved in the winter garden was the presentation of a lar...

Applied Acoustics

Abstract Focusing sound in rooms intended for listening to music or speech is an acoustic defect.... more Abstract Focusing sound in rooms intended for listening to music or speech is an acoustic defect. Design recommendations provide remedial steps to effectively prevent this. However, there is a category of objects of high historical or architectural value in which the sound focus correction is limited or even abandoned. This also applies to indoor or outdoor concert shells, installations for teaching and acoustic presentations, etc. The main content of this article is deriving the equation of a caustic created by a concave hemispherical reflector with a source of rays situated at a given position. It is explained why under real conditions, both indoors and outdoors, no clear caustic resulting from the geometric approach is observed. Instead, its blurred form is perceived, usually limited to the caustic cusp taking the form of a point-like sound focus. This can be attributed to the effect of diffraction and interference, the impact of which on a caustic is analyzed in the paper.

Applied Acoustics, 1991

ABSTRACT The analytical form of the Thiele's coefficient of sound field directional diffu... more ABSTRACT The analytical form of the Thiele's coefficient of sound field directional diffusion has been derived for the case of a diffuse field existing at the presence of the sound source. The derived formula gives the largest value of the coefficient which can be expected in the room of the assumed acoustical absorption, at the given distance from the sound source. The value of the coefficient has also been estimated for real conditions by means of the sound field numerical model based on the ray method. It has been shown that at the non-uniform distribution of sound-absorbing materials in a room, for example in a full concert hall, sound field diffusion is significantly smaller than that resulting from the commonly assumed statistical nature of the sound field in rooms.

Applied Acoustics, 1992

Testing inclusions of a point in a polygon is an important element of various computer models use... more Testing inclusions of a point in a polygon is an important element of various computer models used in architectural acoustics. In this paper, an algorithmic representation of such a test is presented. Different forms of the algorithm are discussed and the form suitable for convex polygons is optimized from a viewpoint of execution time. A room shape analysis is employed to obtain an additional improvement of the algorithm efficiency. The concept of a preliminary checking of a point position prior to the main test execution is also discussed. Altogether, c. 60% reduction of execution time is obtained. Though the algorithms discussed are the ray method oriented, they can also be applied to other methods of sound field modelling in bounded spaces.