scholarly journals Noise Reduction Effect of Noise Barrier for Shinkansen Based on Y-shaped Structure

2006 ◽  
Vol 47 (3) ◽  
pp. 162-168 ◽  
Author(s):  
Kaoru MURATA ◽  
Kiyoshi NAGAKURA ◽  
Toshiki KITAGAWA ◽  
Shin-ichiro TANAKA
Keyword(s):  
Noise Reduction ◽  
Noise Barrier ◽  
Reduction Effect

Minimizing noise from metro viaduct railway lines by means of elastic mats and fully closed noise barriers

2018 ◽  
Vol 232 (6) ◽  
pp. 1828-1836 ◽  
Author(s):  
Caiyou Zhao ◽  
Wang Ping
Keyword(s):  
Noise Reduction ◽  
Vibration Energy ◽  
Rail Transit ◽  
In Situ Experiment ◽  
Noise Barriers ◽  
Transit Systems ◽  
Slab Track ◽  
Noise Barrier ◽  
Reduction Effect

An adverse effect of urban elevated rail transit systems is the associated noise, which has become a source of environmental complaints. In order to effectively address this problem, an in situ experiment has been conducted on the elevated sections of Hangzhou Metro Line 1 involving three cases: a 2.2 m vertical noise barrier with integrated bed track, a 2.2 m vertical noise barrier with an elastic mat floating slab track, and a 5.1 m fully enclosed noise barrier with an elastic mat floating slab track. The noise reduction effects of the elastic mats and the two kinds of noise barriers for metro viaduct railway lines were evaluated, and the mechanisms of these countermeasures were analysed. The results show that elastic mats can effectively reduce the transmission of wheel–rail vibration energy into the bridge, thus decreasing bridge-borne noise; meanwhile, the elastic mats could lead to an increase in wheel–rail noise. An excellent noise reduction effect was achieved in the area below and near the bottom of the bridge, while an increased noise effect was observed close to the area above and near the rail surface. The fully enclosed noise barrier controlled the propagation of wheel–rail noise more effectively than the vertical noise barriers, but no difference was found between these two kinds of noise barriers in controlling bridge-borne noise.

Case study: Prediction and field tests of railway noise and effects of a low-height noise barrier

2020 ◽  
Vol 68 (4) ◽  
pp. 303-314
Author(s):  
Yuna Park ◽  
Hyo-In Koh ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
...  
Keyword(s):  
High Speed ◽  
Field Tests ◽  
Residential Areas ◽  
Railway Systems ◽  
Railway Noise ◽  
Sound Levels ◽  
Noise Barrier ◽  
The Difference ◽  
Reduction Effect ◽  
The Impact

Railway noise is calculated to predict the impact of new or reconstructed railway tracks on nearby residential areas. The results are used to prepare adequate counter- measures, and the calculation results are directly related to the cost of the action plans. The calculated values were used to produce noise maps for each area of inter- est. The Schall 03 2012 is one of the most frequently used methods for the production of noise maps. The latest version was released in 2012 and uses various input para- meters associated with the latest rail vehicles and track systems in Germany. This version has not been sufficiently used in South Korea, and there is a lack of standard guidelines and a precise manual for Korean railway systems. Thus, it is not clear what input parameters will match specific local cases. This study investigates the modeling procedure for Korean railway systems and the differences between calcu- lated railway sound levels and measured values obtained using the Schall 03 2012 model. Depending on the location of sound receivers, the difference between the cal- culated and measured values was within approximately 4 dB for various train types. In the case of high-speed trains, the value was approximately 7 dB. A noise-reducing measure was also modeled. The noise reduction effect of a low-height noise barrier system was predicted and evaluated for operating railway sites within the frame- work of a national research project in Korea. The comparison of calculated and measured values showed differences within 2.5 dB.

scholarly journals Noise Reduction Effect of Superhydrophobic Surfaces with Streamwise Strip of Channel Flow

2021 ◽  
Vol 11 (9) ◽  
pp. 3869
Author(s):  
Chen Niu ◽  
Yongwei Liu ◽  
Dejiang Shang ◽  
Chao Zhang
Keyword(s):  
Reynolds Number ◽  
Drag Reduction ◽  
Noise Reduction ◽  
Channel Flow ◽  
Superhydrophobic Surface ◽  
Sound Field ◽  
Flow Noise ◽  
Slip Boundary ◽  
Eddy Simulation ◽  
Reduction Effect

Superhydrophobic surface is a promising technology, but the effect of superhydrophobic surface on flow noise is still unclear. Therefore, we used alternating free-slip and no-slip boundary conditions to study the flow noise of superhydrophobic channel flows with streamwise strips. The numerical calculations of the flow and the sound field have been carried out by the methods of large eddy simulation (LES) and Lighthill analogy, respectively. Under a constant pressure gradient (CPG) condition, the average Reynolds number and the friction Reynolds number are approximately set to 4200 and 180, respectively. The influence on noise of different gas fractions (GF) and strip number in a spanwise period on channel flow have been studied. Our results show that the superhydrophobic surface has noise reduction effect in some cases. Under CPG conditions, the increase in GF increases the bulk velocity and weakens the noise reduction effect. Otherwise, the increase in strip number enhances the lateral energy exchange of the superhydrophobic surface, and results in more transverse vortices and attenuates the noise reduction effect. In our results, the best noise reduction effect is obtained as 10.7 dB under the scenario of the strip number is 4 and GF is 0.5. The best drag reduction effect is 32%, and the result is obtained under the scenario of GF is 0.8 and strip number is 1. In summary, the choice of GF and the number of strips is comprehensively considered to guarantee the performance of drag reduction and noise reduction in this work.

Application of compact silencers as a noise barrier to a naturally ventilated double-skin façade

2021 ◽  
Vol 69 (3) ◽  
pp. 220-228
Author(s):  
Jeehwan Lee ◽  
Jae D. Chang ◽  
Robert Coffeen
Keyword(s):  
Noise Reduction ◽  
Surface Area ◽  
Natural Ventilation ◽  
Experimental Investigations ◽  
Test Case ◽  
Open Surface ◽  
Low Frequencies ◽  
Noise Barrier ◽  
Double Skin ◽  
Air Vent

A prior study of the acoustical performance of a double-skin facade (DSF) as a noise barrier was carried out based on the percentage of the air vent open surface area, shading louver configurations, and shading louver surface materials. Earlier research findings led to experimental investigations of the acoustical performance capabilities of compact silencers to replace DSF air vents as both noise barriers and air channels because DSF air cavities, which contribute to natural ventilation performance (e.g., wind-driven or buoyancy-driven performance), are acoustically vulnerable to noise transmitted through the air vents. This experimental investigation aims to explore noise reduction (NR) through compact silencers applied to DSF air vents. Double-skin facade mock-up test cases were designed based on three test scenarios of a ventilation open surface area: (1) a 100%air vent open surface area (open mode), (2) a 0% air vent open surface area (closed mode), and (3) a compact silencer. From a data analysis of DSF mock-up test results, the overall NR values of a DSFmock-up ranged from20 to 37 dB(A) depending on the number of compact silencers and the shading louver orientation used. Configurations of compact silencers and shading louvers helped the DSF mock-up achieve additionalNR values of 5 to 10 dB(A) depending on the test case. Moreover, applying compact silencers to a naturally ventilated DSF mock-up led to significant noise reduction at low frequencies (125Hz).

Comparison of Noise Reduction Performance Evaluation Methods for Low-Noise Pavement in Korea- Part

2021 ◽  
Vol 263 (4) ◽  
pp. 2930-2939
Author(s):  
Byungchae Kim ◽  
Hyunjin Kim ◽  
Wonuk Kang
Keyword(s):  
Noise Reduction ◽  
Noise Level ◽  
Measurement Method ◽  
Road Traffic ◽  
Low Noise ◽  
Management Standards ◽  
Close Proximity ◽  
Porous Pavement ◽  
Reduction Effect ◽  
Measurement Location

In Korea, road noise is assessed as a measurement method of exterior noise emitted by road vehicle for management standards by the National Institute of Environmental Sciences. In this method, the noise felt at the actual pickup point is measured as LAeq (the roadside equivalent noise level). Recently, to clarify the standard for measuring noise on low-noise pavements, the CPX (ISO11819-2; Close-proximity method) was first introduced in the Porous Pavement Guidelines of the Ministry of Land, Infrastructure and Transport. According to ISO, the CPX adopts the side microphone as a mandatory measurement location, and the rear optional. The side location has been a mandatory due to its high correlation with SPB (ISO 11819-1, Statistical Pass-by method). However, according to our previous study on the correlation evaluation between L and CPX rear microphone noise level, both noise reduction effect was about 9-12 dB(A) showed a high correlation in Korea where heavy road traffic is common. The following study aims to show the consistent correlation between the L and CPX rear noise level. Furthermore, it is intended to be helpful in selecting the location of the CPX microphone that can most effectively represent the actual noise on the low-noise pavement in Korea.

Sign in / Sign up

Export Citation Format

Share Document