• Title/Summary/Keyword: slope beach

Search Result 68, Processing Time 0.02 seconds

Experimental Study of Shape and Pressure Characteristics of Solitary Wave generated by Sluice Gate for Various Conditions (Sluice Gate를 이용한 고립파 발생조건에 따른 형상 및 압력 특성에 관한 실험적 연구)

  • Cho, Jae Nam;Kim, Dong Hyun;Lee, Seung Oh
    • Journal of the Korean Society of Safety
    • /
    • v.31 no.2
    • /
    • pp.70-75
    • /
    • 2016
  • Recently, coastal erosion has been widely in progress and the erosion level becomes also serious in the world wide, espeically in East Sea in Korea. Since it would threaten the life, economics and security risk, it is necessary to much comprehend the reason why coastal erosion has occurred according to the geographical characteristics. Meanwhile, analysis about hydrodynamics of the solitary wave such as tunami in swash zone is needed for the best management practice of coastal erosion. Solitary wave is nonlinear wave and can be reproduced in the laboratoy scale by openning suddenly a sluice gate with water head difference, of which methodology was found in the literature, since it could be simply determined by a significant wave height. Thus, in this sutdy the generation of solitary wave was experimentalized using the sluice gate. Experimental conditions were classified by angles of a beach slope, a water level in a beach slope and a difference of water level between in a headtank and a channel bed. Two kinds of dimensionless analyses based from experimental results in this study were presented; the first analysis indicates nondimensionalization between the wave height and the water level in a beach slope in order to investigate characteristics of solitary wave approaching the beach. The second shows the other nondimensionalization between dynamic pressure and static pressure on a beach slope to investigate the relationship between wave breaking and wave pressure. Under the same conditions as laboratory experiments, the numerical results computed with a SWAN model embedded in FLOW 3D were compared in terms of wave height, and pressure on the beach slope, which shows good agreement with each other. Overall results from this study could provide fundamental hydraulic data for the reliabile verification of numerical simulation results about coastal erosion in swash zone caused by solitary waves.

Comparisons of the Environmental Characteristics of Intertidal Beach and Mudflat

  • Kim, Tae-Rim
    • Korean Journal of Remote Sensing
    • /
    • v.25 no.3
    • /
    • pp.225-231
    • /
    • 2009
  • The characteristics of morphological shapes, wave heights, tidal ranges and sediment sizes are observed and compared between intertidal beach and mudflat. The Mohang sand beach, southwest coast of Korea, is located just next to the large mudflat and has tidal range over 5 meters. Wave measurements are conducted at each entrance of the beach and mudflat as well as at the outside waters representing the incident waves to these different coastal environments. The morphological characteristics are also examined including the sediment size and the slope of the bathymetry, For the observation of morphological shapes, camera monitoring technique is used to measure the spatial information of intertidal bathymetry. The water lines moving on the intertidal flat/beach durinq a flood indicate depth contours between low and high water lines. The water lines extracted from the consecutive images are rectified to get the ground coordinates of each depth contours and integrated to provide three dimensional information of intertidal topography. The wave data show that sand beach is in the condition of severer wave forcing but tidal range is almost identical in both environment. The slope of the mudflat is much milder than the sand beach with finer sediment.

Comparison of Numerical Methods for Two-dimensional Wave Breaker on a Plane Beach of Constant Slope (2차원 Beach에서 쇄파의 시뮬레이션을 위한 수치계산기법의 비교)

  • Jeong K. L.;Lee Y.-G.
    • 한국전산유체공학회:학술대회논문집
    • /
    • 2004.03a
    • /
    • pp.119-125
    • /
    • 2004
  • Unsteady nonlinear wave motions on the free surface over a plane beach of constant slope are numerically simulated using a finite difference method in rectangular grid system. Two-dimensional Navier-Stokes equations and the continuity equation are used for the computations. Irregular leg lengths and stars are employed near the boundaries of body and free surface to satisfy the boundary conditions. Also, the free surface which consists of markers or segments is determined every time step with the satisfaction of kinematic and dynamic free surface conditions. Moreover, marker-density method is also adopted to allow plunging jets impinging on the free surface. The second-order Stokes wave theory and solitary wave theory are employed for the generation of waves on the inflow boundary. For the simulation of wave breaking phenomena, the computations are carried out with the plane beach of constant slope in surf zone. The results are compared with each other. The marker-density method is better then the hybrid method. Also they are compared with other existing experimental results. The Agreement between the experimental data and the computation results is good.

  • PDF

Beach Erosion during Storm Surge Overlapped with Tide (조위변동을 고려한 폭풍해일시의 해안침식에 관한 연구)

  • 손창배
    • Journal of the Korean Society of Marine Environment & Safety
    • /
    • v.6 no.2
    • /
    • pp.47-56
    • /
    • 2000
  • This paper describes a simple prediction method of beach recession induced by storm surge. In order to evaluate the severest beach erosion, it is assumed that maximum beach recession occurs at the coming of storm surge overlapped with spring tide. Consequently, total surge lev디 becomes the sum of storm surge level and tidal range. Generally, storm surge level around Korea is small compared with tidal range. Therefore total surge can be expressed as the series of surges, which have same duration as tide. Through the case studies, the author Investigates correlation between tidal range, duration, wave condition, beach slope and beach recession.

  • PDF

A Study on Shock Pressure of Breaking wave Exerted Upon Vertical Wall (수직벽상(垂直壁上)의 충격쇄파압(衝擊碎波壓)에 관한 연구(硏究))

  • Lee, Bong Hak;Choi, Han Kuy;Kim, Nam Weon
    • Journal of Industrial Technology
    • /
    • v.8
    • /
    • pp.3-11
    • /
    • 1988
  • Shock pressure of wave breaking on vertical wall is studied experimentally with beaches, which have four different slopes (1/4.02, 1/7.05, 1/10, 1 /13.5). This results is summerized as follows: 1. Maximum impact presures are occured where the wave break directly on the wall rather than breaking in front of the wall. 2. Deep water steepness, and the beach slope are the two Quantities governing the magnitude and location of maximum dimensionless impact pressure from wave breaking directly on the wall, also, the greatest pressure is produced with a beach slope of 1/10. 3. This study is clearly shown that the location of maximum pressure can be presented above still water level under respectively experimental condition. The dimensionless elevation of maximum Pressure is greatest on a beach slope of 1/10.

  • PDF

A Numerical Solution. Method for Two-dimensional Nonlinear Water Waves on a Plane Beach of Constant Slope

  • Lee, Young-Gill;Heo, Jae-Kyung;Jeong, Kwang-Leol;Kim, Kang-Sin
    • Journal of Ship and Ocean Technology
    • /
    • v.8 no.2
    • /
    • pp.61-69
    • /
    • 2004
  • Unsteady nonlinear wave motions on the free surface over a plane beach of constant slope are numerically simulated using a finite difference method in rectangular grid system. Two-dimensional Navier-Stokes equations and the continuity equation are used for the computations. Irregular leg lengths and stars are employed near the boundaries of body and free surface to satisfy the boundary conditions. Also, the free surface which consists of markers or segments is determined every time step with the satisfaction of kinematic and dynamic free surface conditions. Moreover, marker-density method is also adopted to allow plunging jets impinging on the free surface. The second-order Stokes wave theory is employed for the generation of waves on the inflow boundary. For the simulation of wave breaking phenomena, the computations are carried out with the plane beach of constant slope in surf zone. The results are compared with other existing experimental results. Agreement between the experimental data and the computation results is good.

An Experimental Study on the Beach Nourshment Method of HAE UN DAE Beach (해운대 해수욕장에 있어서의 양빈공법에 관한 실험적 연구)

  • 민병형;옥치율;유상호
    • Journal of Ocean Engineering and Technology
    • /
    • v.1 no.1
    • /
    • pp.84-93
    • /
    • 1987
  • A beach nourishment method can be used as one of the beach erosion protection methods which may keep coastal environments whithout constructing coastal structures on the HAE UN DAE beach. The beach nourishmens is affected by a natural condition and artificial condition;a natural condition includes conditions of bottom slope, diameter of bottom materials and waves, and artificial conditions include deposit position, method, diameter and quantity of the nourishing sand. It has accomplished to obtain the deposit position and the best diameter of the nourishing sand from a two-dimensional hydraulic model test, which simulates the erosional HAE UN DAE beach. In this study, the protection of the beach erosion can be maximized when the nourishing sand of 3.3mm in diameter, which is about 5.5.times of the bottom materials in diameter, is deposited layerly in front of the breaker zone which has a water depth of 4.6m.

  • PDF

An Experimental Study on the Beack Nourishment Method of Beach (인공양빈공법에 관한 실험적 연구)

  • 민병형;옥치율;김가현;최도식
    • Journal of Ocean Engineering and Technology
    • /
    • v.2 no.1
    • /
    • pp.163-169
    • /
    • 1988
  • A beach nourishment method can be used as one of the beach. The beach nourishment is affected br a natural condition and an artificial condition; a natural condtion include conditions of bottom slope, diameter of bottom materials and wave, and an artificial condition include deposit position, method, diameter and quantity of the nourishing sand. To obtain and the best diameter of the nourishing sand a two-dimensional hydraulic model test, which simulates the erosional beach, has been accmplished. In this study the protection of the beach erosion can be maximized when the nourishing sand of 0.84mm in diameter, which is about 2.5-3.5 times of the natural bottom materials in diameter.

  • PDF

A Fundamental Investigation on the Marine Environmental Conditions of Bathing Beach in Jeju (제주도 사빈 해수욕장의 해양환경 조건에 관한 기초조사)

  • Kim Nam-Hyeong;Jang Seong-Hun
    • Journal of the Korean Society for Marine Environment & Energy
    • /
    • v.4 no.3
    • /
    • pp.53-64
    • /
    • 2001
  • Bathing beach may be one of the ocean resorts in popular, which peoples can easily access in summer. Three beaches in Jeiu island are surveyed about natural environmental conditions using coastal engineering technique and questionnaire are carried out. Also the satisfaction index on the sand size, wave height, water temperature, transparency and bottom slope is gained very well. The results obtained from this study can be utilized making a new artificial bathing beach in the future.

  • PDF

Analysis of Shoreline Change Using Multi-temporal Remote Sensed Data on Songjeong Beach, Busan (다중시기 원격탐사 자료를 이용한 부산 송정해수욕장의 해안선 변화 분석)

  • Jang, Dong-Ho;Kim, Jang-Soo;Baek, Seung-Gyun
    • Journal of The Geomorphological Association of Korea
    • /
    • v.19 no.4
    • /
    • pp.59-71
    • /
    • 2012
  • This research was carried out to analyze long-term shoreline change on Busan Songjeong Beach using multi-temporal remote sensed data, GPS survey data and grain size analysis. As a result of multi-temporal satellite imagery analysis, the beach was stable status till early 2000s, but the erosion occurred over whole beach after the construction of shore protection road since 2000. In the result of DEM analysis, the elevation of beach reduced and the slope of berm increased after construction of shore protection road along the coast, this means the erosion environment was dominant on the beach. But the sedimentation was slightly stronger than the erosion in northern region of the beach, then the slope of berm was gentle. In the result of grain size analysis using in-situ samples, the coarsening-trend was found in southeastern region (Line E) of the beach, it is caused by strong wave energy from the outer sea. Consequently, major causes of the beach erosion in the study area were the interception of sand supply from a dune owing to shore protection road construction and scouring phenomenon by strong wave energy in southeastern region of the beach. If the topographic or artificial change will not occur in the future, the erosion in this area will continue. Therefore the prevention measures are required.