• Title/Summary/Keyword: breaking energy

Search Result 299, Processing Time 0.023 seconds

Energy Dissipation and Transfer among Wave Components during Directional Breaking Processes (다방향 쇄파 발생 전후의 파랑 성분간 에너지 전이 및 소산)

  • 홍기용;에스똘히오메자
    • Journal of Ocean Engineering and Technology
    • /
    • v.17 no.6
    • /
    • pp.1-6
    • /
    • 2003
  • Wave energy dissipation and energy transfer between wave components, during the directional wave breakings, are investigated. Directional incipient and plunging breakers were generated by focusing the multi-frequency and multi-directional wave components at a designed location, based on a constant wave amplitude and a constant wave steepness frequency spectrum. The time series of surface wave elevation was measured at 9 different locations around the wave focusing point, using a wave gauge array. In order to examine the variation of the directional spreading function, the horizontal velocity of fluid motion was also measured. By comparing energy spectrums, before and after the breaking, the characteristics of energy dissipation and energy transfer, caused by wave breaking, are investigated. Their dependencies on directionality, as well as frequency, are analyzed. The breakings significantly dissipate wave energy, through energy transfer, in the upper region of the peak-frequency band, while enhancing wave energy in the low-frequency band.

An Experimental Study on Wave Energy Variation through Breaking Processes (쇄파과정에서의 파랑에너지 변화에 관한 실험연구)

  • Cho, Won-Chul
    • Journal of Korean Society of Coastal and Ocean Engineers
    • /
    • v.6 no.2
    • /
    • pp.157-163
    • /
    • 1994
  • An experimental study of deep-water breaking waves is performed by nonlinear wave evolution as well as superposition of different wave frequencies. Two-dimensional and three-dimensional wave instabilities and breakings are observed in nonlinear wave evolution. The wave energy evolves with almost the same initial wave energy before breaking but decreases significantly after breaking process. Large spilling and plunging waves are generated near e expected breaking location by means of faster waves overtaking slow waves at a certain point. More energy loss in vigorous plunging breakers is observed through breaking process.

  • PDF

A Economic Feasibility Analysis of Energy Saving Technology Application to Underground Subway Station

  • Kim, Hyungchul;Shin, Seungkwon;Jung, Hosung;Kim, Jin-o;Cha, Junmin
    • International Journal of Internet, Broadcasting and Communication
    • /
    • v.7 no.2
    • /
    • pp.36-40
    • /
    • 2015
  • In Korea, new total energy-saving solution has planned to build test-bed in underground subway station. Breaking energy is one of the most energy saving method in railway, but it has not be fully used up for economical purpose. This paper demonstrates on energy saving technology application including breaking energy and heating energy to underground subway station. It also offer solution of optimization of power energy flow. Moreover, economic feasibility analysis performed for undergound test bed constuction.

Evolution of Surface Profiles of Breaking Waves Generated by Directional Wave Focusing (다방향 파랑집중에 의한 쇄파의 파형특성 연구)

  • Hong Keyyong;Choi Hak-Sun
    • Journal of the Korean Society for Marine Environment & Energy
    • /
    • v.5 no.1
    • /
    • pp.11-18
    • /
    • 2002
  • Directional breaking waves are generated by the component wave focusing both in direction and frequency based on constant wave steepness and constant wave amplitude spectrum models. The generated breaking waves are classified in the incipient, single and multi breaking waves. The characteristics of directional breaking waves are investigated in terms of surface profile parameters of wave crest steepness and asymmetry. The evolution of breaking wave characteristics is analyzed in a view of focusing efficiency. It shows that the front steepness and vertical asymmetry play an important role in breaking process, while the crest rear steepness and horizontal asymmetry are nearly constant during the process. The superposition of directional components greatly enhances the focusing efficiency and it suggests that characteristics of directional breaking waves may significantly different from uni-directional ones.

  • PDF

Assessment of cutting performance and chip breaking characteristics with a nondimensional parameter consists of cutting condition and tool shape factor(l) -Orthogonal cutting- (절삭 조건과 공구 형상 인자로 구성된 무차원 파라미터에 의한 절삭 성능 및 칩절단 특성 평가(I))

  • LEE, Young-Moon;CHOI, Won-Sik;SEO, Seok-Won
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.11 no.6
    • /
    • pp.179-184
    • /
    • 1994
  • In this study a nondimensional parameter, feed/land length(F/L) was introduced, and using this parameter, cutting performance and chip breaking characteristics of the groove and the land angle type chip formers were assessed. Specific cutting energy consumed and shape of broken chip with its breaking cycle time were appraised to find out the ranges of F/L value where efficient cutting and effective chip breaking could be achieved. C type chip was found out to be the most preferable in terms of cutting efficiency.

  • PDF

Wave Breaking Characteristics over Composite Slope Section (복합단면지형에서의 파랑의 쇄파변형특성)

  • 권혁민;요시미고다;최한규
    • Journal of Korean Society of Coastal and Ocean Engineers
    • /
    • v.7 no.2
    • /
    • pp.135-140
    • /
    • 1995
  • The procedure of wave energy dissipation due to breaking has been investigated with trains of the regular wave. To obtain the data for wave breaking and its deformation, experiments have been conducted by utilizing a horizontal step adjoining to a combined slope of 1/20 and 1/10. After breaking the wave height decreases by dissipation but attains a stable value at some distance from the breaking point Experimental results show that the stable wave is considerably affected by the wave period. The study gives the general form of stable wave height A new one-dimensional wave deformation model is proposed. being coupled with an approximated shoaling coefficient before wave breaking and the new energy dissipation term after breaking. It was compared with the experimental data. It predicts well the wave height deformation before and after wave breaking even on the abrupt change of the depth.

  • PDF

Chip breaking characteristics using non-dimensional parameter in metal cutting (절삭 가공시 무차원 파라미터에 의한 칩 절단특성)

  • Choi, Won-Sik
    • Journal of the Korean Society of Industry Convergence
    • /
    • v.2 no.2
    • /
    • pp.181-186
    • /
    • 1999
  • For an unmanned machining system, the control and disposal of chips is one of the most serious problems at present. In order to perform chip control, feed/land length($F_L$) was introduced, and using this parameter, the cutting performance and chip breaking characteristics of groove-type and the land -angle-type chip formers were assessed. The specific cutting energy consumed and the shape of broken chips with its breaking cycle time were evaluated to find out the ranges of $F_L$ value where efficient cutting and effective chip breaking could be achieved. The C type chip was found to be the most preferable from the view point of cutting efficiency.

  • PDF

Wave Breaking and Breaking Wave-Induced High Frequency Pressure over Submerged Breakwater (잠제에 의한 쇄파 및 쇄파에 의해 발생하는 고주파수파동압)

  • Koichiro IWATA;Koji KAWASAKI;Hirokazu SUMI
    • Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
    • /
    • 2002.08a
    • /
    • pp.14-23
    • /
    • 2002
  • Wave breaking and breaking wave-induced hydrodynamics are very important subjects in the field of coastal and ocean hydrodynamics and engineering. In the coastal zone, a submerged breakwater has been increasingly popular, since it is one of nature-matching structures with multi- functions such as (1) wave energy dissipation by wave breaking and friction, (2) oxygen supply to sea by wave breaking and breaking wave, (3) water purification by entrained air bubbles, (4) keeping. good seascape. and (5) good habitat for sea livings. Recently, the breaking wave-induced high frequency pressure over a submerged breakwater is said to have a function of gathering sea livings around the structure, which has encouraged the construction of the submerged breakwater in coastal zone. (omitted)

  • PDF

The Characteristics of Wave Energy Variations by Impermeable Submerged Breakwater Using VOF Method in Irregular Wave Fields (VOF 법에 의한 불규칙파동장에 있어서 불투과잠제에 의한 파랑에너지 변형특성)

  • 허동수;김도삼
    • Journal of Korean Society of Coastal and Ocean Engineers
    • /
    • v.15 no.4
    • /
    • pp.207-213
    • /
    • 2003
  • This study is to numerically investigate the characteristics of wave energy variations propagating over impermeable submerged breakwaters with irregular waves. Two-dimensional numerical wave flume based on the VOF method was used. VOF method is the most efficient capable of simulating free surfaces including wave breaking. From the computed frequency spectrum results, wave breaking play important role in ability of the submerged breakwaters to dissipate incident wave energy. In case of occurring wave breaking, our analysis shows that wave energy moves to short wave period on one-row impermeable submerged breakwater's lee side and is widely distributed not having peak period on two- row impermeable submerged breakwater's lee side.

Modeling of Wave Breaking in Spectral Wave Evolution Equation (스펙트럼 파랑모형에서의 쇄파모형)

  • Cho, Yong-Jun;Ryu, Ha-Sang
    • Journal of Korean Society of Coastal and Ocean Engineers
    • /
    • v.19 no.4
    • /
    • pp.303-312
    • /
    • 2007
  • There is still a controversy going on about how to model energy dissipation due to breaking over frequency domain. In this study, we unveil the exact structure of energy dissipation using stochastic wave breaking model. It turns out that contrary to our present understanding, energy dissipation is cubically distributed over frequency domain. The verification of proposed model is conducted using the acquired data during SUPERTANK Laboratory Data Collection Project (Krauss et al., 1992). For further verification, we numerically simulate the nonlinear shoaling process of Conoidal wave over a beach of uniform slope, and obtain very promising results from the viewpoint of a skewness and asymmetry of wave field, usually regarded as the most fastidious parameter to satisfy.