• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2317-2328
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• 2013

In this study, the effect of wave chamber slab on wave pressure along the first and second wall of the perforated caisson breakwater was investigated by performing physical experiment. The experiment was performed without and with the wave chamber slab of the perforated caisson by varying the front wall porosity. The discrepancy in magnitudes of the measured wave pressure along the both walls of the perforated caisson was apparent according to the existence of the wave chamber slab as significantly greater pressures were acquired for all the test cases when the wave chamber was closed upward by the slab. As a result, the magnitudes of the total wave force calculated by integration of the measured wave pressure also were much larger for the caisson breakwater having the wave chamber slab, exceeding the value based on the well known Takahashi's formula (Takahashi and Shimosako, 1994). With respect to the porosity of the front wall, meanwhile, higher pressures were obtained with a larger porosity, at both the first and second wall of the breakwater.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.573-584
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• 2013

This study experimentally investigated the change in distribution of wave pressure on the front wall according to the variation of the front wall porosity of the caisson breakwater having the cap of wave chamber. First, the wave pressure for the non-porous caissson corresponding to zero porosity was measured and compared with the pressure formula suggested by Goda(1974). The analysis showed that the measured pressure distribution fairly well agreed with the Goda formula, which confirmed the accurate measurement of wave pressure in the present experiment. In case of the porous caisson, meanwhile, the experiment was performed by varying the front wall porosity as 0.2, 0.25, and 0.3. The wave pressure distribution at the front wall showed little difference according to the porosity for most of the test wave conditions, whereas the pressure slightly increased with the porosity for some test waves whose wave heights and periods were relatively large. However, the difference according to the porsosity was insignificant for the wave force at the front wall.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.1
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• pp.119-128
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• 2015

This study investigates the wave pressure characteristics of the pile-supported breakwater with single or double perforated walls through 2-D hydraulic experiments and the measured wave pressures are compared to those of wave pressures by Goda's formula. For single chamber, the measured wave pressures in the front wall and rear wall decreased to about 25% and 30%, respectively, compared to those of wave pressures by Goda's formula. Also, the decrease in the wave pressures for double chamber were about 27%, 53%, and 64% in the front wall, middle wall, and rear wall, respectively. It was found that the pile-supported breakwater with double perforated walls was more efficient than the single chamber due to wave dissipation effects of double slit walls with horizontal slits.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.12
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• pp.835-839
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• 2012

In recent decades, a lot of noise barriers have been installed along paved road in order to reduce the road induced noise, which increases as traffic volume grows. For better range of sight, transparent noise barriers are widely installed despite of reflecting noise. In this study, the effect of surface shape and pattern of noise barriers on the reduction of reflecting noise was analyzed to maximize the noise reduction. According to the number of shape and pattern, it was observed that there were noise reduction effect as of 0.9~1.5 dB(A). It was found that the spatial field where the noise concentrates or disperses changes according to the width of blocks on the barriers as well. It suggests that there might be possibility of surface shape modification to optimize the noise reduction technology.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5B
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• pp.301-312
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• 2012

This study investigates the wave height distributions in front of a perforated wall generated by obliquely incident monochromatic waves through laboratory experiments conducted in a wave basin. Attention is paid to the difference or similarity between a plain wall and a perforated wall. And the investigation is focused on the chamber width and side wall effects of a perforated wall on the propagation characteristics of waves. The main results of this study show that the normalized wave height along a perforated wall is a significant difference compare to a plain wall cases. The side wall in the chamber suppresses the growth of the stem waves.

• 월간 기계설비
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• s.37
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• pp.73-84
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• 1993

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.5
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• pp.335-341
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• 2014

Physical experiments were carried out to measure the wave force on the vertical walls of perforated breakwater considering several phases of a wave acting on the breakwater. The maximum horizontal wave force acting on each vertical wall was compared between single and double chamber caisson breakwater. The experimental data in this study showed that the total horizontal wave force for double chamber caisson was 9.6% smaller on average than that for single chamber caisson when the total chamber width was the same for both caissons. Such reduction of the wave force is due to the dissipation of wave energy at the porous middle wall, which is located between the porous front wall and non-porous rear wall.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2009.10a
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• pp.180-183
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• 2009

월파조건에서 직립벽을 따른 연파특성에 대한 실험을 수행하고 그 결과를 비교하였다. 제체전면을 따른 파고분포를 살펴보면, 상대여유고에 따른 파고변화는 어느 정도 나타났다. 제체 직각 방향으로의 결과에서 상대파고의 감소는 연파의 폭범위내에서 나타나는 것을 확인할 수 있었다. 향후 보다 자세한 분석과 월파량과 연계한 분석을 수행할 예정이다.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1993.07a
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• pp.55-58
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• 1993

유공식 방파제는 기존 직립 혼성방파제의 케이슨 전면에 유공벽과 유수실을 설치함으로써 교량이 유공벽을 통과하여 유수실내로 진입할 때 와유 등에 의해 접근 파랑에너지를 감소시킬 수 있도록 고안된 구조형식을 갖는다. 따라서, 방파제 주변의 항로유지에 있어서 기존 직립 혼성방파제에 비해 우수한 특성을 지닌 형태이다. 이러한 방파제 형태는 일본에서는 다수 시공되어 성공적으로 운영되고 있으나 국내에서는 아직도 이렇다 할 시공실적이 없다. (중략)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.677-678
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• 2013