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김상현,박남식,정봉석,이동훈 대한상하수도학회 1999 상하수도학회지 Vol.13 No.2
A simulation of water hammer, introduced by abruptly waried motion of a pumping machine, was performed at a one of typical pumping station in Korea. Impact of hydraulic structure such as check valve, pressure relief valve and air valve in miti-gating water hammer effect was estimated gradually. Method of characteristic was employed for the effective calculation of discharge and head. The relationship between various hydraulic structures and flow was properly integrated on the base of the method of characteristic. The methodology in this approach can provide signifi-cant contribution in decision making procedure for the design of hydraulic structure at a typical pumping station in Korea.
김상현,박남식,김주인,정봉석,도중호 대한상하수도학회 2001 상하수도학회지 Vol.15 No.3
The characteristics of unsteady pipe flow to an external impact such as valve modulation can be detected in a frequency domain. Fast Fourier Transformation is employed to convert the head variation in the time domain to the amplitude of the frequency domain. Application of the method of characteristics to a pipeline provides a range of frequency representing a particular unsteady condition. Inverse Fast Fourier Transformation and a Finite Impulse Response Filter can be used to remove noise present in the frequency range. Characteristics of the frequency range for various conditions such as valve modulation and a minor modification of a pipeline are explored to demonstrate the effectiveness of the noise control method in the frequency domain. A noise contaminated signal was successfully filtered using a low pass filter, which was designed from a frequency analysis of head variation.