• Title/Summary/Keyword: Tunnel Noise

Search Result 428, Processing Time 0.025 seconds

3-Dimensional Computations of the Weak Shock Wave Discharged from the Exit of Duct (관출구로부터 방출되는 약한 충격파에 관한 3 차원 수치해석)

  • Kweon, Yong-Hun;Shin, Hyun-Dong;Kim, Heuy-Dong;Lee, Dong-Hoon
    • Proceedings of the KSME Conference
    • /
    • 2003.04a
    • /
    • pp.1742-1747
    • /
    • 2003
  • When a shock wave is discharged from the exit of a duct, complicated flow is formed near the duct exit. The flow field is much more complicated under the ground effects or any other objects near the exit of a duct, such as the circumstance near the exit of the high-speed railway tunnel. The resulting flow is essentially three-dimensional unsteady with the effects of strong compressibility. In the current study, three-dimensional flow fields of the weak shock wave which is discharged from the exit of a duct are numerically investigated using a CFD method. Computations are performed for the weak shock wave in the range below 1.5. The results obtained show that the directivity and magnitude of the weak shock discharged strongly depend upon the Mach number of initial shock wave and are significantly influenced by the ground effects.

  • PDF

Flow Analyses around Intake within Sump in a Pump Station (펌프장에서 Sump내 흡입구 주위의 유동해석)

  • Roh Hyung-Woon;Kim Jae-Soo;Suh Sang-Ho
    • Proceedings of the KSME Conference
    • /
    • 2002.08a
    • /
    • pp.597-600
    • /
    • 2002
  • In general, the function of intake structure, whether it be a open channel, a fully wetted tunnel, a sump or a tank, is to supply an evenly distributed flow to a pump station. An even distribution of flow, characterized by strong local flow, can result in formation of surface or submerged vortices, and with certain low values of submergence, may introduce air into pump, causing a reduction of capacity and efficiency, an increase in vibration and additional noise. Uneven flow distribution can also increase or decrease the power consumption with a change in total developed head. To avoid these sump problems pump station designers are considered intake structure dimensions, such as approaching upstream, baffle size, sump width, width of pump cell and so on. From this background, flow characteristics of intake within sump are Investigated numerically to obtain the optimal sump design data. The sump model is designed in accordance with HI code.

  • PDF

Detailed Analysis of Ground Vibration in Subway Tunnel (지하철 터널구간에서의 지반진동 상세해석)

  • Lee il-wha;Hwang seon-keun;Joh sung-ho;Ko hak-song
    • Proceedings of the KSR Conference
    • /
    • 2005.05a
    • /
    • pp.722-725
    • /
    • 2005
  • Recently, ground-borne noise and vibration generated by underground transit system has been recognized as an important environmental problem. This study reviews several of the improved procedures that have been used to predict ground-borne vibration. At first, ground stiffness profile is examined by SASW test which is the most reasonable surface wave test. It is very important to acquire the exact ground stiffness profile at ground response analysis. At second, the train loading to act roadbed is calculated by using the real measured phase angle data. In finite element analysis, averaged acceleration method, infinite element, Rayleigh damping and 2-dimensional wave propagation analysis is performed.

  • PDF

The Standard of Sump Design in Pump Station (펌프장내 흡수정 설계 기준)

  • Roh, H.W.;Oh, O.S.;Lee, Y.H.
    • 유체기계공업학회:학술대회논문집
    • /
    • 2005.12a
    • /
    • pp.589-592
    • /
    • 2005
  • In general, the function of intake structure, whether it be a open channel, a fully wetted tunnel, a sump or a tank, is to supply an evenly distributed flow to a pump station. An even distribution of flow, characterized by strong local flow, can result in formation of surface or submerged vortices, and with certain low values of submergence, may introduce air into pump, causing a reduction of capacity and efficiency, an increase in vibration and additional noise. Unfortunately in order to design the sump station, the reasonable code or the standards weren't presented yet in Korea. Thus, some researchers had often referred the HI code, JSME code or CEN code to design the sump station. This study aims to prescribe the standard of sump design which were matched well the Korean pump station. Thus, the HI code and TSJ code would be interpreted fully to Korean language, the part of interpreted clauses of the western codes would be selected to compose the standard.

  • PDF

A Study on Parameter Estimation for General Aviation Canard Aircraft

  • Kim, Eung Tai;Seong, Kie-Jeong;Kim, Yeong-Cheol
    • International Journal of Aeronautical and Space Sciences
    • /
    • v.16 no.3
    • /
    • pp.425-436
    • /
    • 2015
  • This paper presents the procedures used for estimating the stability and control derivatives of a general aviation canard aircraft from flight data. The maximum likelihood estimation method which accounts for both process and measurement noise was used for the flight data analysis of a four seat canard aircraft, the Firefly. Without relying on the parameter estimation method, several aerodynamic derivatives were obtained by analyzing the steady state flight data. A wind tunnel test, a flight test of a 1/4 scaled remotely controlled model aircraft, and the prediction of aerodynamic coefficients using the USAF Stability and Control Digital Data Compendium (DATCOM), Advanced Aircraft Analysis (AAA), and Computer Fluid Dynamics (CFD) were performed during the development phase of the Firefly and the results were compared with flight determined derivatives of a full scaled flight prototype. A correlation between the results from each method could be used for the design of the canard aircraft as well as for building the aerodynamic database.

Simultaneous Measurements of Velocity Fields at Two Vertically Crossing Planes by PIV Systems Using Polarization Technique (편광기법을 이용한 수직교차평면의 PIV 속도장 동시측정)

  • Kwon S. H.;Yoon S. Y,;Kim K. C.
    • Journal of the Korean Society of Visualization
    • /
    • v.2 no.1
    • /
    • pp.32-38
    • /
    • 2004
  • A new PIV technique was developed for decreasing optical error which was created during simultaneous measurements of velocity fields at a wall-normal plane and wall-parallel plane by a plane PIV and a Stereo-PIV systems. For experimental study, two different Reynolds number based on momentum thickness, Re$_{ =514 and 934 were generated in a blowing type wind tunnel under the condition of zero pressure gradient. The two Nd:Yag laser systems and three CCD cameras were synchronized. to obtain instantaneous velocity fields at the same time. To avoid optical noise at the crossing line by the two laser light sheets, a new optical arrangement using polarization was applied. The obtained velocity fields show the existence of hairpin packet structure vividly and the idealized hairpin vortex signature is confirmed by experiment.

  • PDF

Blasting Utilizing Non-electric Detonator and Its Principle Planning and Operation (비전기 뇌관의 발파와 기본 설계 및 시공)

  • Choi Young-Cheon
    • Explosives and Blasting
    • /
    • v.22 no.4
    • /
    • pp.23-29
    • /
    • 2004
  • Non-electric detonator was developed to improve the blasting efficiency of electric detonator. It is increasingly utilized in surface and tunnel blasting due to its safety in external electric shock, precise delayed time, and decrease in blasting vibration and noise. The paper describes the detonating system of non-electric detonator, principle operating and planning methods, and case history so that it can be contributed to improve blasting technology.

Development of optical temperature distribution measurement system for Underground Power Transmission tunnel (지중선로의 분포 온도 측정 시스템 개발)

  • Lee, Keun-Yang;Song, Woo-Sung
    • Proceedings of the KIEE Conference
    • /
    • 1998.07b
    • /
    • pp.766-768
    • /
    • 1998
  • Optical Temperature Distribution measurement System (OTDS) is completely different from conventional electric point sensor in that it uses the optical fiber itself as the sensor. This new concept in temperature measuring system requires only one fiber to be laid. The use of optical fiber also gives the advantage of small diameter, light weight, explosion resistance, and electromagnetic noise resistance. The OTDS is a sensor which is capable of making a precise measurement over a wide range of areas using only a single optical fiber. Since current temperature sensors, such as the thermocouple, are only used to measure temperaturea of point, they are almost impractical for measuring a wider range because of the extremely high cost. In comparision with current sensors, the optical fiber distributed temperature sensor can make much quicker and more precise measurements at a comparatively low cost.

  • PDF

Vibration and Noise Level on the Training Ship Pusan 403 (실습선 부산 403호의 진동과 소음)

  • Park, Jung Hee
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.23 no.2
    • /
    • pp.8-8
    • /
    • 1987
  • This paper describes on the distribution of the vibration and the noise produced on a skipjack pole and line training ship M/S Pusan 403 (243GT, 1,000ps) under the cruising or drifting condition. The vibration and the noise level were measured by use of protable vibration analyzer (B and K 3513) and sound level meter (B and K 2205), and so the vibration level was converted into dB unit. The check points were set through every decks and around important places of the ship. The results obtained can be summarized as follows: 1. The vibration and the noise level 1) On the main deck, both the vibration and the noise level were highest at the vertically above the main engine, whereas the vibration level was the lowest in the bow store and the noise level beneath the bridge. 2) Under cruising condition, the vibration level around the cylinder head of main engine, port side of the engine room, on the shaft tunnel was 80, 67, 65 dB and the noise level 104, 87, 86 dB, respectively. 3) The vibration level on the vertical line passing through the bridge was the highest at the orlop deck with 60 dB and the lowest on the bridge deck with 55 dB, whereas the noise level the highest at the compass deck with 75 dB and the lowest at the orlop deck with 53 dB. 4) The vibration and the noise level on the open decks were the highest with 65 dB and 84 dB on the boat deck, whereas the vibration level was the lowest at the lecture room with 51 dB and the noise level the lowest at the fore castle deck with 57 dB. 5) On the orlop decks, both the vibration and the noise level were the highest at the engine room with 65 dB and 85 dB, and the lowest at bow store with 54 dB and 52 dB, respectively. Comparing with the vibration level and the noise level, the vibration level was higher than the noise level in the bow part and it was contrary in the stern part of the ship. 2. Vibration analysis 1) The vibration displacement and the vibration velocity were the greatest at the cylinder head of main engine with 100μm and 11mm/sec, and were the smallest at the compass deck with 3μm and 0.07mm/sec. They were also attenuated rapidly around the frequency of 100Hz and over. 2) The vibration acceleration was the greatest at the cylinder head with the main frequency of 1KHz and the acceleration of 1.1mm/sec super(2), and the smallest at the compass deck with 30KHz and 0.05mm/sec super(2).

Vibration and Noise Level on the Training Ship Pusan 403 (실습선 부산 403호의 진동과 소음)

  • 박중희
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.23 no.2
    • /
    • pp.54-60
    • /
    • 1987
  • This paper describes on the distribution of the vibration and the noise produced on a skipjack pole and line training ship M/S Pusan 403 (243GT, 1,000ps) under the cruising or drifting condition. The vibration and the noise level were measured by use of protable vibration analyzer (B and K 3513) and sound level meter (B and K 2205), and so the vibration level was converted into dB unit. The check points were set through every decks and around important places of the ship. The results obtained can be summarized as follows: 1. The vibration and the noise level 1) On the main deck, both the vibration and the noise level were highest at the vertically above the main engine, whereas the vibration level was the lowest in the bow store and the noise level beneath the bridge. 2) Under cruising condition, the vibration level around the cylinder head of main engine, port side of the engine room, on the shaft tunnel was 80, 67, 65 dB and the noise level 104, 87, 86 dB, respectively. 3) The vibration level on the vertical line passing through the bridge was the highest at the orlop deck with 60 dB and the lowest on the bridge deck with 55 dB, whereas the noise level the highest at the compass deck with 75 dB and the lowest at the orlop deck with 53 dB. 4) The vibration and the noise level on the open decks were the highest with 65 dB and 84 dB on the boat deck, whereas the vibration level was the lowest at the lecture room with 51 dB and the noise level the lowest at the fore castle deck with 57 dB. 5) On the orlop decks, both the vibration and the noise level were the highest at the engine room with 65 dB and 85 dB, and the lowest at bow store with 54 dB and 52 dB, respectively. Comparing with the vibration level and the noise level, the vibration level was higher than the noise level in the bow part and it was contrary in the stern part of the ship. 2. Vibration analysis 1) The vibration displacement and the vibration velocity were the greatest at the cylinder head of main engine with 100$\mu$m and 11mm/sec, and were the smallest at the compass deck with 3$\mu$m and 0.07mm/sec. They were also attenuated rapidly around the frequency of 100Hz and over. 2) The vibration acceleration was the greatest at the cylinder head with the main frequency of 1KHz and the acceleration of 1.1mm/sec super(2), and the smallest at the compass deck with 30KHz and 0.05mm/sec super(2).

  • PDF