Modelling of Scattering from Balcony Fronts

2002 ◽  
Vol 9 (3) ◽  
pp. 219-231
Author(s):  
T. M. Chan ◽  
W. M. To
Keyword(s):  
Computer Simulation ◽  
Ray Tracing ◽  
Diffuse Reflection ◽  
Sound Field ◽  
Direct Wave ◽  
Practice Experience ◽  
Concert Halls ◽  
Distinguished Group ◽  
Opera Houses

Balconies are normally used in large auditoria such as concert halls or opera houses, to increase seating capacity or to give better view for a distinguished group of the audience. When ray-tracing based computer models are applied to study the acoustical quality of these auditoria, the alteration of the sound field due to balcony fronts is normally unobservable, because of the relative small size of the balcony fronts in the auditorium. Furthermore, most diffuse reflection ray-tracing methods are not based on direct wave acoustics but on an approximation of the scattering effect. In practice, experience shows that balcony fronts give additional warmth to music. This effect is more prominent when singers perform in traditional horseshoe shaped opera houses with multi-levels balconies. This paper describes modelling of scattering from balcony fronts using a theoretical wave approach, in which the incident wave front is not plane but spherical. A computer simulation illustrates the scattering of sound that takes place when the wavefront impinges on the surface of the balcony fronts.

A discussion on building technology in the 1980s - Acoustics of concert and multi-purpose halls

1972 ◽  
Vol 272 (1229) ◽  
pp. 621-625 ◽  
Keyword(s):  
Computer Simulation ◽  
Considerable Part ◽  
Design Problems ◽  
Building Technology ◽  
The Past ◽  
Music Making ◽  
Scale Models ◽  
The Future ◽  
Concert Halls

The 1980s are likely to see a continuation of the trend of the past 25 years of an expansion in the quantity, and improvement in the quality, of public music making. Concert halls are usually prestigious buildings, and often no expense is spared to make the acoustics as good as possible, but the design problems are still formidable. In the 1980s some considerable help in design may be expected from scale models and computer simulation. And electronic aids for acoustics may become more common. The problems of multi-purpose halls are rather different; the conflicting acoustic requirements for speech and for music have to be reconciled, and cost is important. Here electronic techniques may play a considerable part in the future.

scholarly journals Research on the Manufacturing Quality of Co-Cured Hat-Stiffened Composite Structure

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2747
Author(s):  
Xiangwen Ju ◽  
Jun Xiao ◽  
Dongli Wang ◽  
Cong Zhao ◽  
Xianfeng Wang
Keyword(s):  
Composite Structures ◽  
Sound Pressure ◽  
Integration Method ◽  
Complex Geometry ◽  
Sound Field ◽  
Thickness Measurement ◽  
Curing Process ◽  
The Finite Element Method ◽  
Manufacturing Quality

The stringer-stiffened structure is widely used due to its excellent mechanical properties. Improving the manufacturing quality of stringer-stiffened structure which have complex geometry is important to ensure the bearing capacity of aviation components. Herein, composite hat-stiffened composite structures were manufactured by different filling forms and bladders with various properties, the deformation of silicone rubber bladder in co-curing process was studied by using the finite element method. The thickness measurement at different positions of the hat-stiffened structure was performed to determine the best filling form and bladder property. Moreover, in view of the detection difficulties in R-zone of stringer, numerical simulation was performed to get the sound pressure and impulse response of at the R-zone of stringer by Rayleigh integration method, and an effective equipment which could stably detect the manufacturing quality of R-zone was designed to verify the correctness of sound field simulation and realize the detection of stringer. With the optimum filling form and bladder properties, hat-stiffened composites can be manufactured integrally with improved surface quality and geometric accuracy, based on co-curing process.

Numerical Analysis of the Acoustical Quality of a Multi-Purpose Hall

1995 ◽  
Vol 2 (3) ◽  
pp. 487-500 ◽  
Author(s):  
X.W. Meng ◽  
G. De Borger ◽  
M. Van Overmeire
Keyword(s):  
Computer Simulation ◽  
Sound Pressure Level ◽  
Decay Time ◽  
Sound Pressure ◽  
Field Measurements ◽  
Pressure Level ◽  
Energy Fraction ◽  
Experimental Values ◽  
Simulation Package

In this paper, the acoustical features are described of a multi-purpose auditorium of the Free University of Brussels which were investigated both with field measurements and computer simulation. The convergence of the algorithm of the simulation package RAYNOISE was investigated as a function of the influence on the calculated results of the choice of the number of rays and the reflection order. By comparing the numerical and experimental values of the sound pressure level and early decay time, it is demonstrated that sufficiently accurate acoustical models can be developed. Based on these models, acoustical quantities such as the early energy fraction, sound pressure level, early decay time and early lateral energy fraction were calculated and employed to evaluate the acoustical quality of this multi-purpose hall.

Acoustical Design Study on Application of Absorption Materials

2014 ◽  
Vol 711 ◽  
pp. 546-549
Author(s):  
Wei Lin ◽  
Wei Hwa Chiang
Keyword(s):  
Computer Simulation ◽  
Energy Distribution ◽  
Ray Tracing ◽  
Impulse Response ◽  
Background Noise ◽  
Three Dimensional ◽  
Design Phase ◽  
Design Study ◽  
Sound Energy ◽  
Reinforcement System

Taipei Top Church Auditorium is a hall primarily intended for praise and worship. A three dimensional ray tracing computer simulation was used to provide sound energy distribution on the audience area of the hall, realistic design have been performed. The volume of the hall is 24600m3, which is occupied for 2200 people and equipped the hall with acoustical curtains by modifying its acoustical characteristics. Objective measurements of impulse response are reported, and background noise control and noise isolation are also be considered in the design phase. Reinforcement system is conducted to meet all the activity for the acoustical environments.

scholarly journals APPLICATION OF 3-D VELOCITY MODELS AND RAY TRACING IN DOUBLE DIFFERENCE EARTHQUAKE LOCATION ALGORITHMS: APPLICATION TO THE MYGDONIA BASIN (NORTHERN GREECE)

2004 ◽  
Vol 36 (3) ◽  
pp. 1396 ◽  
Author(s):  
O. C. Galanis ◽  
C. B. Papazachos ◽  
P. M. Hatzidimitriou ◽  
E. M. Scordilis
Keyword(s):  
Ray Tracing ◽  
Velocity Structure ◽  
Test Site ◽  
Earthquake Location ◽  
Double Difference ◽  
Northern Greece ◽  
Local Networks ◽  
Velocity Models ◽  
Earthquake Locations

In the past years there has been a growing demand for precise earthquake locations for seismotectonic and seismic hazard studies. Recently this has become possible because of the development of sophisticated location algorithms, as well as hardware resources. This is expected to lead to a better insight of seismicity in the near future. A well-known technique, which has been recently used for relocating earthquake data sets is the double difference algorithm. In its original implementation it makes use of a one-dimensional ray tracing routine to calculate seismic wave travel times. We have modified the implementation of the algorithm by incorporating a three-dimensional velocity model and ray tracing in order to relocate a set of earthquakes in the area of the Mygdonia Basin (Northern Greece). This area is covered by a permanent regional network and occasionally by temporary local networks. The velocity structure is very well known, as the Mygdonia Basin has been used as an international test site for seismological studies since 1993, which makes it an appropriate location for evaluating earthquake location algorithms, with the quality of the results depending only on the quality of the data and the algorithm itself. The new earthquake locations reveal details of the area's seismotectonic structure, which are blurred, if not misleading, when resolved by standard (routine) location algorithms.

Measurement of Bulk Electrical Properties Using GPR with a Variable Reflector

2018 ◽  
Vol 23 (4) ◽  
pp. 489-496
Author(s):  
J. David Redman ◽  
A. Peter Annan ◽  
Nectaria Diamanti
Keyword(s):  
Electrical Properties ◽  
Moisture Content ◽  
Ground Penetrating Radar ◽  
Arrival Time ◽  
Wood Chip ◽  
Direct Wave ◽  
Trace Data ◽  
Ground Penetrating ◽  
Prototype Instrument

Bulk electrical properties of media are important inherently for ground penetrating radar (GPR) applications and for providing a means to determine indirectly other physical properties such as moisture content. We have developed a reflector whose reflectivity can be controlled electronically. This variable reflector controlled by a GPR provides an effective method to measure bulk electrical properties of media. For sample measurements, the GPR is placed on one side of a sample and the variable reflector on the opposite side. GPR trace data are then acquired with the reflector in an on-state and in the off-state. By differencing these measurements, we improve the ability to detect the specific reflection event from the variable reflector. This process removes both the direct wave and clutter from the trace data, improving the quality of the refection event and our ability to accurately pick its arrival time and amplitude. We describe the variable reflector, a prototype instrument based on the reflector and numerical modeling performed to understand its response. We also show the results of testing applications to the measurement of wood chip moisture content and monitoring of the electrical properties of concrete during the curing process.

Eco-Disasters

2021 ◽  
pp. 65-88
Author(s):  
Helen Goodman
Keyword(s):  
Quality Of Life ◽  
Emergency Management ◽  
Social Workers ◽  
Force Fields ◽  
Community Networks ◽  
Community Life ◽  
Practice Experience ◽  
Communities Of Place ◽  
Post Disaster

This chapter seeks to encourage social workers to review their often (enforced) siloed roles in relation to communities of place and to develop stronger senses about the relationships and networks in places where those they serve actually live. The author offers a picture of force fields, system tensions which shape organizational and community life in particular ways, ways which diminish community life, and those who seek to serve community, and she provides examples from her practice experience in pre and post disaster environments. Where social workers can contribute to strengthening community networks, this will contribute to a quality of life for those they serve and then strengthen the capability of community responsiveness to a disaster. Seeing, valuing, and using these links may allow social workers to make subtle but important contributions to the field of emergency management.

scholarly journals Analysis of Various Ventilation Systems Due to the Quality of Indoor Air in Educational Buildings

Proceedings ◽  
2019 ◽  
Vol 16 (1) ◽  
pp. 29
Author(s):  
Katarzyna Gładyszewska-Fiedoruk ◽  
Vasyl Zhelykh ◽  
Andrii Pushchinskyi
Keyword(s):  
Carbon Dioxide ◽  
Computer Simulation ◽  
Air Quality ◽  
Knowledge Acquisition ◽  
Indoor Air ◽  
Educational Buildings ◽  
Building Ventilation ◽  
Ventilation Systems

The quality of internal air is one of the factors that affect the pace and quality of knowledge acquisition. Therefore, it is important that the classrooms have high air quality. Using computer simulation, the effect of various building ventilation variants on air quality in classrooms was analyzed. As an indicator of air quality, the concentration of carbon dioxide in school halls was assumed.

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