덕동댐 유역의 유출해석에 관한 연구

권혁민,강인식 경주대학교 2000 論文集 Vol.13 No.-

Four different methods. Clark area routing method. SCS TR-55, Nakayasu synthetic hint hydrograph, and kajiyama formula were used to calculate the desi후 flood for Deok Dong reservoir watershed located in Kyung Ju. The results obtained using Clark area routing method were determined as the design flood for the watershed. The recurrence interval of 500 years was selected for the watershed. The design runoff hydrographs were routed through reservoir using the Puls method. The actual storm events which were relatively large in their magnitudes were also analyzed. The outflow calculated in this study showed considerable differences from results available in the literatures. The several errors that can not be ignored found in the literatures were indicated and explained to provide more accurate results for the watershed. Some basic informations useful for the prevention of disaster due to heavy storms were proposed.

방파제의 신뢰성 설계에 의한 중량식의 비교

권혁민 경주대학교 2002 論文集 Vol.15 No.-

Hanzawa et a1 (1996)calculated damages of armor blocks using Monte-Carlo simulation for horizontally composite breakwaters. In their calculation, one dimensional wave breaking model by Goda(1975) was used. But in the real sea area, incident waves have variability of wave directions including directional spreading parameter, refraction and deviation of mean wave directions. In this study, reliability based design was executed using three dimensional random wave breaking model by Kweon(1998) instead of one dimensional wave breaking model by Goda(1975). As a result, considering variability of wave directions, thedamages of armor blocks are calculated to be smaller than those of Hanzawa et a1 (1996). The damages of armor blocks calculated using van der Meer(1988b) stability formula for Tetrapods also show similar results. Reliability based design for breakwater armor blocks has been executed on the assumption of unidirectional waves. But, if variability of wave directions is considered, the economic design can be expected.

하프록의 상재하중 추정을 위한 실험적 연구

권혁민 경주대학교 2001 論文集 Vol.14 No.-

Half-loc has been investigated for an alternative material of natural stone consists of filter layer of rubble mound breakwater. In this study, the load on the Half-loc combination gave been set for measuring the load. The data show 1) 40ton Tetrapod of 2-layer placement gives load of about 40ton on a Half-loc 2) the normal load of a slope have bigger than load on plane flat calculated by arithmetic average method.

Experimental study on the method of estimating the vertical design wave force acting on a submerged dual horizontal plate

Kweon, Hyuck-Min,Oh, Sang-Ho,Choi, Young-Hwan The Society of Naval Architects of Korea 2013 International Journal of Naval Architecture and Oc Vol.5 No.4

A steel-type breakwater that uses a submerged dual horizontal porous plate was originally proposed by Kweon et al. (2005), and its hydrodynamic characteristics and design methodology were investigated in a series of subsequent researches. In particular, Kweon et al. (2011) proposed a method of estimating the vertical uplift force that acts on the horizontal plate, applicable to the design of the pile uplift drag force. However, the difference between the method proposed by Kweon et al. (2011), and the wave force measured at a different time without a phase difference, have not yet been clearly analyzed. In this study, such difference according to the method of estimating the wave force was analyzed, by measuring the wave pressure acting on a breakwater model. The hydraulic model test was conducted in a two-dimensional wave flume of 60.0 m length, 1.5 m height and 1.0 m width. The steepness range of the selected waves is 0.01~0.03, with regular and random signals. 20 pressure gauges were used for the measurement. The analysis results showed that the wave force estimate in the method of Kweon et al. (2011) was smaller than the wave force calculated from the maximum pressure at individual points, under a random wave action. Meanwhile, the method of Goda (1974) that was applied to the horizontal plate produced a smaller wave force, than the method of Kweon et al. (2011). The method of Kweon (2011) was already verified in the real sea test of Kweon et al. (2012), where the safety factor of the pile uplift force was found to be greater than 2.0. Based on these results, it was concluded that the method of estimating the wave force by Kweon et al. (2011) can be satisfactorily used for estimating the uplift force of a pile.

Experimental study on the method of estimating the vertical design wave force acting on a submerged dual horizontal plate

Hyuck-Min Kweon,Sang-Ho Oh,Young-Hwan Choi 대한조선학회 2013 International Journal of Naval Architecture and Oc Vol.5 No.4

A steel-type breakwater that uses a submerged dual horizontal porous plate was originally proposed by Kweon et al. (2005), and its hydrodynamic characteristics and design methodology were investigated in a series of subsequent researches. In particular, Kweon et al. (2011) proposed a method of estimating the vertical uplift force that acts on the horizontal plate, applicable to the design of the pile uplift drag force. However, the difference between the method proposed by Kweon et al. (2011), and the wave force measured at a different time without a phase difference, have not yet been clearly analyzed. In this study, such difference according to the method of estimating the wave force was analyzed, by measuring the wave pressure acting on a breakwater model. The hydraulic model test was conducted in a two-dimensional wave flume of 60.0 m length, 1.5 m height and 1.0 m width. The steepness range of the selected waves is 0.01~0.03, with regular and random signals. 20 pressure gauges were used for the measurement. The analysis results showed that the wave force estimate in the method of Kweon et al. (2011) was smaller than the wave force calculated from the maximum pressure at individual points, under a random wave action. Meanwhile, the method of Goda (1974) that was applied to the horizontal plate produced a smaller wave force, than the method of Kweon et al. (2011). The method of Kweon (2011) was already verified in the real sea test of Kweon et al. (2012), where the safety factor of the pile uplift force was found to be greater than 2.0. Based on these results, it was concluded that the method of estimating the wave force by Kweon et al. (2011) can be satisfactorily used for estimating the uplift force of a pile.

A study of the optimum draft of multiple resonance power buoys for maximizing electric power production

Kweon, Hyuck-Min,Cho, Hong-Yeon,Cho, II-Hyoung The Society of Naval Architects of Korea 2014 International Journal of Naval Architecture and Oc Vol.6 No.4

To maximize electric power production using wave energy extractions from resonance power buoys, the maximum motion displacement spectra of the buoys can primarily be obtained under a given wave condition. In this study, wave spectra observed in shoaling water were formulated. Target resonance frequencies were established from the arithmetic means of modal frequency bands and the peak frequencies. The motion characteristics of the circular cylindrical power buoys with corresponding drafts were then calculated using numerical models without considering PTO damping force. Results showed that the heave motions of the power buoys in shoaling waters with insufficient drafts produced greater amplification effects than those in deep seas with sufficient drafts.

An array effect of wave energy farm buoys

Kweon, Hyuck-Min,Lee, Jung-Lyul The Society of Naval Architects of Korea 2012 International Journal of Naval Architecture and Oc Vol.4 No.4

An ocean buoy energy farm is considered for Green energy generation and delivery to small towns along the Korean coast. The present study presents that the floating buoy-type energy farm appears to be sufficiently feasible for trapping more energy compared to affixed cylinder duck array. It is also seen from the numerical results that the resonated waves between spaced buoys are further trapped by floating buoy motion.Our numerical study is analyzed by a plane-wave approximation, in which evanescent mode effects are included in a modified mild-slope equation based on the scattering characteristics for a single buoy.

A study of the optimum draft of multiple resonance power buoys for maximizing electric power production

Hyuck-Min Kweon,Hong-Yeon Cho,II-Hyoung Cho 대한조선학회 2014 International Journal of Naval Architecture and Oc Vol.6 No.4

To maximize electric power production using wave energy extractions from resonance power buoys, the maximum motion displacement spectra of the buoys can primarily be obtained under a given wave condition. In this study, wave spectra observed in shoaling water were formulated. Target resonance frequencies were established from the arithmetic means of modal frequency bands and the peak frequencies. The motion characteristics of the circular cylindrical power buoys with corresponding drafts were then calculated using numerical models without considering PTO damping force. Results showed that the heave motions of the power buoys in shoaling waters with insufficient drafts produced greater amplification effects than those in deep seas with sufficient drafts.

Effects of reverse waves on the hydrodynamic pressure acting on a dual porous horizontal plate

Hyuck-Min Kweon,Young-Hwan Choi 대한조선학회 2014 International Journal of Naval Architecture and Oc Vol.6 No.1

The seaward reverse wave, occurring on the submerged dual porous horizontal plate, can contribute to the reduction of the transmitted wave as it reflects the propagating wave. However, the collision between the propagating and seaward reverse waves increases the water level and acts as a weight on the horizontal plate. This study investigated the characteristics of the wave pressure created by the seaward reverse wave through the analysis of experimental data. The analysis confirmed the following results: 1) the time series of the wave pressure showed reverse phase phenomena due to the collision, and the wave pressures acted simultaneously on both upper and lower surfaces of the horizontal plate; 2) the horizontal plate became repeatedly compressed and tensile before and after the occurrence of the seaward reverse wave; and 3) the seaward reverse wave created the total wave pressure to the maximum towards the direction of gravity, primarily on the upper plate. It was also confirmed that the wave distributions showed a similar trend to the wave steepness. Such outcome of the analysis will provide basic information to the structural analysis of the horizontal plate as a wave dissipater of the steel-type breakwater (STB).

Heaving displacement amplification characteristics of a power buoy in shoaling water with insufficient draft

Kweon, Hyuck-Min,Cho, Il-Hyoung,Cho, Hong-Yeon The Society of Naval Architects of Korea 2013 International Journal of Naval Architecture and Oc Vol.5 No.4

The resonance power buoy is a convincing tool that can increase the extraction efficiency of wave energy. The buoy needs a corresponding draft, to move in resonance with waves within the peak frequency band where wave energy is concentrated. However, it must still be clarified if the buoy acts as an effective displacement amplifier, when there is insufficient water depth. In this study, the vertical displacement of a circular cylinder-type buoy was calculated, with the spectrum data observed in a real shallow sea as the external wave force, and with the corresponding draft, according to the mode frequency of normal waves. Such numerical investigation result, without considering Power Take-Off (PTO) damping, confirmed that the area of the heave responses spectrum can be amplified by up to about tenfold, compared with the wave energy spectrum, if the draft corresponds to the peak frequency, even with insufficient water depth. Moreover, the amplification factor of the buoy varied, according to the seasonal changes in the wave spectra.