نتایج جستجو برای: acoustic noise

تعداد نتایج: 271819  

Journal: :international journal of advanced design and manufacturing technology 0
mohamadhosein navidfar saeed ziyaee rad mohamad esfahanian amir khorram

in this paper the interior noise level of a vehicle due to structural vibration, named structure borne noise, as a part of nvh analysis has been investigated. first structural analysis is performed and vibrational behavior of structure carried out due to power plant excitations. then interior acoustic cavity response for such excitation and resultant noise is determined. vibrational analysis is...

Aerospace engines testing is a source of noise pollution and determining the low frequency acoustic characteristics of the test cell, plays an important role in optimally control of the sound field and reducing the level of sound pressure and pollution. In this study, the drop in average sound pressure level is numerically predicted by constructing a test cell according to ISO 140 standard. To ...

Journal: :نشریه دانشکده فنی 0
دکتر هوشنگ پاکزاد

noise level intensity in cities, due to the daily increasing sources of noise producing agents in one respect, and the lack of noise absorbants in the other respect, is rising. the high influence of intense noises on the human body and mind are found to have detrimental effects. the ideal is to have an optimal condition of noise. in this paper the living and relaxing areas, in view of main acou...

A. Omidvar F. Khalvati

In this paper, a novel analytical method was developed based on statistical energy analysis framework to evaluate sound transmission loss through ventilated windows. The proposed method was compared to numerical and analytical models available in the literature. Results showed the success and advantage of the proposed model in predicting the acoustic performance of the ventilated window and the...

Transparent acoustic sensors and actuators are a new generation of acoustic transducers that can create an evolution in the microphone and loudspeakers industries. These transducers with properties like transparency, flexibility, flatness, very low weight and thickness have a great potential for various applications like public speakers, active noise cancelation systems, displays, cell phones a...

In this paper, the acoustic analysis of noise has been done in automotive cabin at high speed. High-frequency noise sources are applied separately to the roof and floor panels as well as to the windshield of the vehicle, which has been investigated at both the driver's and rear passenger's head. The most important panels that have the most noise emission are specified. In order to analyze high ...

This research has been carried out to determine the marine propeller hydro-acoustic characteristics by Reynolds-Averaged Navier-Stokes (RANS) solver in both uniform and non-uniform wake flow at different operating conditions Wake flow can cause changes in pressure fluctuation and gas effect on propeller noise spectrum. Noise is generated by the induced trailing vortex wake and induced pressure ...

Journal: :The Journal of the Acoustical Society of America 1976

In this paper, a new method is proposed for DOA estimation of correlated acoustic signals, in the presence of unknown spatial correlation noise. By generating a matrix from the signal subspace with the Hankel-SVD method, the correlated resource information is extracted from each eigen-vector. Then a joint-diagonalization  structure is constructed of the signal subspace and basis it, independent...

Journal: :iranian journal of fuzzy systems 2012
s. r. mousavi-aghdam m. b. b. sharifian m. r. banaei

this paper presents a new control structure to reduce torque ripple in switched reluctance motor. although srm possesses many advantages in motor structure, it suers from large torque ripple that causes some problems such as vibration and acoustic noise. in this paper another control loop is added and torque ripple is de ned as an objective function. by using fuzzy sliding mode strategy, the dc...

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