Open Access
Strategic noise map of a major road carried out with two environmental prediction software packages
(Springer Netherlands, 2010) Arana Burgui, Miguel; San Martín Murugarren, Ricardo; San Martín Erviti, María Luisa; Aramendía Santamaría, Emilio; Física; Fisika
The main objective of this study is to analyze the differences found in the results of noise mapping using two of the most popular software techniques for the prediction of environmental noise. The location selected to conduct the comparative study is an area encompassed by the ring road that surrounds the city of Pamplona and on a grid, with a total of 6 × 105 points, approximately. In fact, and as the Environmental Noise Directive points out, it is a major road designated by a Member State (Spain). Configuration of the calculation parameters (discretization of the sources, ground absorption, reflection order, etc.) was as equivalent as possible as far as programs allow. In spite of that, a great number of differences appear in the findings. Although in 95.5% of the points the difference in the noise level calculated from the two programs was less than 3 dB, this general statistic result concealed some great differences. These are due to the various algorithms that programs implement to evaluate noise levels. Most differences pertain to highly screened receivers or remote ones. In the former, the algorithm of visibility is the main cause of such differences. In the latter, differences are mainly brought about by a different implementation of the propagation under homogeneous and favorable atmospheric conditions from both software systems.
Open Access
Measurement and analysis of mechanical noise in wind turbines
(Institute of Acoustics, 2016) Arana Burgui, Miguel; Machín Mindán, Jorge; San Martín Murugarren, Ricardo; Ciencias; Zientziak
Open Access
Sistema basado en tecnología 5G de monitorización psicoacústica del paisaje sonoro en smart cities con offloading computacional dinámico en el Edge
(Sociedade Portuguesa de Acústica, 2020) Segura García, Jaume; Felici Castell, Santiago; Álvarez Calero, José M.; Wang, Qi; López Ballester, Jesús; Fayos, Rafael; Pérez Solano, Juan J.; Arana Burgui, Miguel; Institute for Advanced Materials and Mathematics - INAMAT2
En las tecnologías de próxima generación, el control de las molestias por ruido ambiental en una Smart City debería ser lo más eficiente posible. Los sistemas IoT sobre tecnologías 5G ofrecen una gran oportunidad para hacer offloading del cómputo en los nodos sensores, ya que proporciona una serie de nuevos conceptos para el cómputo dinámico que las tecnologías anteriores no ofrecían. En este artículo, se ha implementado un sistema IoT completo basado en tecnología 5G para la monitorización psicoacústica utilizando diferentes opciones para descargar el cómputo a diferentes partes del sistema. Esta descarga se ha realizado mediante el desarrollo de diferentes splittings funcionales de los algoritmos de cálculo de las métricas psicoacústicas. Por último, se muestra una comparación del rendimiento entre los diferentes splittings funcionales y su aplicación con un análisis detallado.
Open Access
Gaseous fueling of an adapted commercial automotive spark-ignition engine: simplified thermodynamic modeling and experimental study running on hydrogen, methane, carbon monoxide and their mixtures
(Elsevier, 2023) Urroz Unzueta, José Carlos; Diéguez Elizondo, Pedro; Arzamendi Manterola, Gurutze; Arana Burgui, Miguel; Gandía Pascual, Luis; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias; Zientziak; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
In the present work, methane, carbon monoxide, hydrogen and the binary mixtures 20 % CH4–80 % H2, 80 % CH4–20 % H2, 25 % CO–75 % H2 (by volume) were considered as fuels of a naturally aspirated port-fuel injection four-cylinder Volkswagen 1.4 L spark-ignition (SI) engine. The interest in these fuels lies in the fact that they can be obtained from renewable resources such as the fermentation or gasification of residual biomasses as well as the electrolysis of water with electricity of renewable origin in the case of hydrogen. In addition, they can be used upon relatively easy modifications of the engines, including the retrofitting of existing internal combustion engines. It has been found that the engine gives similar performance regardless the gaseous fuel nature if the air–fuel equivalence ratio (λ) is the same. Maximum brake torque and mean effective pressure values within 45–89 N⋅m and 4.0–8.0 bar, respectively, have been obtained at values of λ between 1 and 2 at full load, engine speed of 2000 rpm and optimum spark-advance. In contrast, the nature of the gaseous fuel had great influence upon the range of λ values at which a fuel (either pure or blend) could be used. Methane and methane-rich mixtures with hydrogen or carbon monoxide allowed operating the engine at close to stoichiometric conditions (i.e. 1 < λ < 1.5) yielding the highest brake torque and mean effective pressure values. On the contrary, hydrogen and hydrogen-rich mixtures with methane or carbon monoxide could be employed only in the very fuel-lean region (i.e. 1.5 < λ < 2). The behavior of carbon monoxide was intermediate between that of methane and hydrogen. The present study extends and complements previous works in which the aforementioned fuels were compared only under stoichiometric conditions in air (λ = 1). In addition, a simple zero-dimensional thermodynamic combustion model has been developed that allows describing qualitatively the trends set by the several fuels. Although the model is useful to understand the influence of the fuels properties on the engine performance, its predictive capability is limited by the simplifications made.
Open Access
Zwicker's annoyance model implementation in a WASN node
(Sociedad Española de Acústica, 2019) Pastor Aparicio, Adolfo; López Ballester, Jesús; Segura García, Jaume; Felici Castell, Santiago; Arana Burgui, Miguel; Ciencias; Zientziak
Wireless Acoustic Sensor Network (WASN) nodes for noise measurement and acoustic environment description is a common use in the environmental measurement within the Smart City. The implementation of the psycho-acoustic parameters in each WASN node is a tricky problem and currently is the battle horse in the automatic acoustic environment description. In this work, the implementation and the improvement of the algorithms used for each psycho-acoustic parameter is described and the performance of the implementation measured.
Open Access
Uncertainties caused by source directivity in room-acoustic investigations
(Acoustical Society of America (ASA), 2008) San Martín Murugarren, Ricardo; Arana Burgui, Miguel; Física; Fisika
Although deviations in the measurement of acoustic parameters should be lower than the subjectively perceivable change in the corresponding parameter measured, this study reflects that directionality of sound sources could cause wide audience areas to break away from this criterion at high frequencies, even when using dodecahedron loudspeakers which meet the requirements of the ISO 3382 standard. The directivity of four different acoustic sources was measured and the influence of its accurate orientation spatially quantified in five enclosures for speech and music. By means of simulation software, the number of receivers affected by uncertainties greater than difference limens was established.
Open Access
Characterization of combustion anomalies in a hydrogen-fueled 1.4 L commercial spark-ignition engine by means of in-cylinder pressure, block-engine vibration, and acoustic measurements
(Elsevier, 2018) Diéguez Elizondo, Pedro; Urroz Unzueta, José Carlos; Sáinz Casas, David; Machín Mindán, Jorge; Arana Burgui, Miguel; Gandía Pascual, Luis; Institute for Advanced Materials and Mathematics - INAMAT2
Abnormal combustion phenomena are among the main hurdles for the introduction of hydrogen in the transportation sector through the use of internal combustion engines (ICEs). For that reason the challenge is to guarantee operation free from combustion anomalies at conditions close to the ones giving the best engine output (maximum brake torque and power). To this end, an early and accurate detection of abnormal combustion events is decisive in order to allow the electronic control unit deciding suitable correcting actions. In this work, an automotive size 4-cylinder 1.4 L naturally aspirated port-fuel injection spark ignition Volkswagen engine adapted to run on hydrogen has been investigated. Three distinct methods (in-cylinder pressure, block-engine vibration and acoustic measurements) have been employed to detect abnormal combustion phenomena provoked through the enrichment of the hydrogen-air mixture fed to the cylinders under a wide range of engine speeds (1000–5000 rpm). It has been found that the high-frequency components of the in-cylinder pressure and block engine acceleration signals obtained after a Fourier transform analysis can be used for very sensitive detection of knocking combustion cycles. In the case of the ambient noise measurements, a spectral analysis in terms of third octave bands of the signal recorded by a microphone allowed an accurate characterization. Combustion anomalies could be detected through more intense octave bands at frequencies between 250 Hz and 4 kHz in the case of backfire and between 8 kHz and 20 kHz for knock. Computational fluid dynamics simulations performed indicated that some characteristics of the engine used such as the cylinder valves dimensions and the hydrogen flow rate delivered by the injectors play important roles conditioning the likelihood of suffering backfire events.
Open Access
Diversos errores y dificultades en la enseñanza-aprendizaje de la acústica física y algunas propuestas de mejora
(Sociedade Portuguesa de Acústica, 2024) Arana Burgui, Miguel; San Martín Murugarren, Ricardo; Eguinoa Cabrito, Rubén; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2
Tras más de dos décadas de enseñanza de la acústica en primeros cursos universitarios, hemos observado algunas de las principales dificultades que los alumnos muestran en la comprensión del fenómeno acústico, en sus diferentes campos. Las podemos agrupar en tres categorías. En primer lugar, la dificultad de entender el modelo físico al que se aplican las ecuaciones, medio continuo frente a medio discreto, modificando drásticamente el concepto de ‘partícula’ que siempre han utilizado en la mecánica del punto material. En segundo lugar, la dificultad de diseñar e implementar prácticas experimentales que ayuden a ‘visualizar’ y ‘medir’ las magnitudes acústicas involucradas. Finalmente, la asimilación del cambio de la herramienta matemática que se suele utilizar (notación compleja frente a real), a la cual no se le suele dedicar apenas una justificación clara en los libros de texto. En este trabajo se discuten estos aspectos. Mostraremos los principales errores conceptuales detectados en las pruebas de evaluación y se proponen varias sugerencias que, creemos, pueden ayudar a los docentes de esta materia para intentar mitigar las deficiencias detectadas y mejorar el proceso de aprendizaje de la acústica en nuestros grados universitarios.
Open Access
Aprendizaje basado en casos en la enseñanza de la Acústica Arquitectónica: acondicionamiento acústico del gimnasio de una escuela para utilizarlo como sala de conferencias
(Sociedade Portuguesa de Acústica, 2024) San Martín Murugarren, Ricardo; Arana Burgui, Miguel; Eguinoa Cabrito, Rubén; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2
El Aprendizaje Basado en Casos (Case-Based Learning, CBL) es una de las metodologías activas de aprendizaje cooperativo más empleadas, sobre todo en escuelas de negocios o estudios de derecho, pero también en últimos cursos de ingeniería. Consiste en crear situaciones similares a las que los estudiantes se enfrentarán en su vida profesional al finalizar sus estudios. Esta comunicación presenta una experiencia desarrollada en la asignatura Acústica Arquitectónica del Grado en Ingeniería en Tecnologías de Telecomunicación de la Universidad Pública de Navarra. El caso diseñado recrea una de las actividades profesionales a las que se enfrenta habitualmente un ingeniero acústico: el acondicionamiento de un recinto por deficiencia acústica, reforma o cambio de uso. Se describen aspectos curriculares, planificación, materiales disponibles, método de evaluación y resultados obtenidos, junto con la valoración tanto del profesorado como del alumnado.
Open Access
Influence of recording technology on the determination of binaural psychoacoustic indicators in soundscape investigations
(Institute of Noise Control Engineering, 2019) San Martín Murugarren, Ricardo; Arana Burgui, Miguel; Ezcurra Guisasola, María Amaya; Valencia Leoz, Ana; Ciencias; Zientziak
The evaluation of soundscapes is mainly carried out through field surveys, using soundwalking methodologies. Through rating scales and annotation of comments, the experiences and expectations of the participants are collected. Acoustic and psychoacoustic indicators are also reported to achieve a complete description of the acoustic environment. Binaural measurement systems should be used for registration in order to consider the way in which humans perceive the acoustic environment. Artificial heads or in-ear binaural microphones are the usual devices for this purpose. Further recording technology such as sound field microphones or microphone arrays are also used in soundscape investigations. These methods can provide a higher level of immersion in a later reproduction of the recorded soundscape through multi-channel setups. However, in contrast to direct binaural recordings, the determination of binaural psychoacoustic indicators requires to perform binaural synthesis by means of Head-Related Transfer Functions and signal processing. In this communication, the influence of different recording devices on obtaining psychoacoustic indicators such as binaural loudness and sharpness is analysed.