This study evaluates the serviceability of floating structures designed for marine cities by incorporating wave-dissipating modules. Small-scale model tests in a 2D wave flume were conducted to compare with and without these modules under different conditions (1-year 100-year return period waves). The results showed that significantly reduced vertical acceleration, reductions approximately 44~45% levels 1-year waves 54~57% waves. When topside building was included, similarly pronounced,...

In this study, a three-dimensional numerical model was developed based on modal analysis and substructure method. The devised employed for an evaluation of the dynamic response bottom-mounted platform with pile-soil foundation system that subjected to random waves currents. A two-dimensional scheme Newmark β method extended three dimensions. equation motion solved by using cylindrical beam elements analyze superstructure, impedance function system. displacement bending stress at selected...

The interaction of water waves with partially porous-surfaced circular cylinders was investigated. A three-dimensional numerical modeling developed based on the complete mathematical formulation eigenfunction expansion method in potential flow. Darcy’s law applied to describe porous boundary. partial-porous cylinder is composed a body near free surface, and an impermeable-surfaced end-capped rigid bottom below region. optimal ratio portion impermeable can be adopted design effective ocean...

This study presented a novel circular cofferdam for offshore bridges consisting of ring segments and investigated its structural behaviors using ANSYS Mechanical. Because the bottom segment which has double sleeve cross-section was installed by suction, contact wall lid plate during installation are important design were also analyzed. Prior to numerical investigation complete after dewatering, suction modeling analysis proposed evaluate seepage analysis. Hydrodynamic loads applied evaluated...

This paper presents the results of wave force tests conducted on three types offshore support structures considering eight waves and sea levels to investigate corresponding forces. As a result this study, it is found that occurrence shoaling in shallow water induces significant increase force. Most test models at undergo nonlinear with higher height increasing. In addition, larger diameter structure within range diffraction effect is, due suppressed. Under an irregular water, long-period...

A fast, reliable and optimized numerical procedure of the hydrodynamic response analysis a slender-body structure is presented. With this method, dynamic reliability six-leg jack-up-type wind turbine installation vessel under various environmental conditions analyzed. The modified Morison equation used to calculate wave wind-driven current excitation forces on members. Det Norske Veritas (DNV) rule-based formula loads acting superstructure jack-up leg. From modal analysis, natural period...

In this study, the hydrodynamic characteristics of various types jack-up legs for a wind turbine installation vessel were analyzed. Using modified Morison equation, wave and current excitation forces on calculated. A modal analysis was performed to predict dynamic responses legs. The Newmark-beta time integration scheme used solve equation motion in waves domain. maximum displacement bending stress computed four different legs, their results compared select an optimum leg type. Finally,...

This Paper considers the heading and depth control problem for an underactuated AUV (Autonomous Underwater Vehicle) HW200. The HW200 is a torpedo-type that developed from Hanwha corporation R&D Center military operation such as MCM (Mine Counter Measures). controls horizontal vertical motion with two stern plane rudder plane. It well known fine of not easy because model uncertainties, highly nonlinear coupled motions. To overcome those kind number methods have been presented. In this paper,...

In this study, analytical study to optimally arrange the multi-piles and concrete base parts of steel-concrete hybrid substructure for offshore wind was carried out. order minimize wave force wave-induced bending moment subjected system, diffraction structural analysis were out three types height. As results indicated about 20.6 ~ 24.7 % level comparing with mono-pile extreme condition. Wave-induced at foundation pile head similar height 8.0 m case. Therefore, in certify same safety...

For the reliable design of substructure supporting offshore wind turbines it is very important to reduce effects wave forces. Since strongly influenced by forces as size increases. In present study, hybrid with multi-cylinder newly suggested Using diffraction theory scattering waves in a fluid region are expressed an Eigenfunction expansion method three dimensional potential calculate force acting on substructure. The and run-up presented examine water interaction according variation...

In this paper, for the case of “service life extension” with same capacity wind turbines, a structural safety evaluation was carried out to determine whether extend service aged foundation. As result study, it found that foundation satisfies material strength, ultimate fatigue life, and serviceability up present. Although in-service period has been over 16 years, shown properties concrete have exceeded design no significant deterioration occurred. Also, could be evaluated more realistically...

The water wave interactions on any three-dimensional structure of arbitrary geometry can be calculated numerically through the use source distribution or Green's function techniques. However, such a method computationally expensive. In present study, in floating circular cylinder arrays were investigated using eigenfunction expansion with three- dimensional potential theory to reduce computational expense. excitation force, added mass coefficient, radiation damping and run-up are presented...

In order to reduce the wave excitation forces on structures, partial porous cylinder, which is composed of a part located near free surface and rigid bounded top bottom by impermeable end caps, newly suggested. The fluid domain thus divided into three regions: single exterior region, N inner regions beneath calculate force scattering in each region expressed an Eigenfunction expansion method with using 3-dimension liner potential theory. simplify effect porosity, Darcy's law also applied...

In this study, wave force tests were carried out for the four types of offshore support structures with scale factor 1:25 and forces to structure shapes investigated. As results it was found that, as period increased at normal condition, decreased most cases. Extreme affected by impact force. Impact study significantly effect on Monopile slightly GBS Hybrid type. Accordingly, type indicated even lower extreme irregular conditions than although higher condition regular because larger area...

When a generator trips, the frequency of system begins to drop but control action governors generators stops and restore it quasi steady state. At state, output each is determined by constant damping load. But, in many cases, measured value trajectories outputs differ from theoretical values. The difference considered due complex properties non-linearity models. In this paper, we suggest calculation method constants load primary reserve requirements using real power trajectory data sets past...

The substructure for offshore wind turbines is strongly influenced by the effect of wave forces as size increases. Therefore, it very important to reduce force acting on substructures. In present study hybrid substructure, which composed a multi-cylinder having different radius near free surface and gravity at bottom multi-cylinder, suggested forces. fluid domain divided into two regions calculate with scattering in each region expressed an Eigen-function expansion method. comparison between...

In order to increase the gross generation of wind turbines, size a tower and rotor-nacelle becomes larger. other words, substructure for offshore turbines is strongly influenced by effect wave forces as increases. addition, since large turbine has heavy dead load, reaction on become severe, thus very firm foundations should be required. Therefore, dynamic soil-structure interaction fully considered acting accurately calculated. present study ANSYS AQWA used evaluate forces. The run up are...

In this paper, lane detection technology used as an essential image recognition for the autonomous driving has been dealt with. particular, possibility of real-time operation during night time in Korean road environments were studied. To end, addition to existing foreign terrain daytime training data, additional was performed by constructing dataset and nighttime environments. As a result with dataset, it possible achieve accuracy improvement 92.4 % from 76.9 roads 10–14 ms latency.

This study proposes a new hybrid wave energy converter composed of horizontal cylinder and swing plate to improve the capture width ratio. The generates electrical by using potential incident wave, whereas produces kinetic water particles. can ratio efficiently combining energies generated these two different sources. power-generating performance proposed is evaluated experimentally through hydraulic model test at scale 0.3 in two-dimensional tank direct conversion dynamo PTO (Power...

Energy storage is a key issue when integrating large amounts of intermittent and non-dispatchable renewable energy sources into electric power systems. To maintain the instantaneous balance to compensate for influence fluctuations from sources, flexible capability control needed. Adjustable Speed Pumped Storage Power Generator pumped unit that adjustable pump output adjustments as well highest efficiency operations because it has fast response time. In this paper we address speed generator...

Using the substructure method, numerical models of pile-soil interaction diagonal and diamond types jack-up legs were developed for dynamic response analysis. Wave current forces acting on leg calculated using modified Morison equation. Wind load was computed DNV formula. Modal analysis performed to estimate eigenvalues structure. The Newmark-beta method used calculate behaviors structure in time domain Maximum displacement bending stress each type leg. Reliability carried out both obtain a...

Towers and rotor-nacelles are being enlarged to respond the need for higher gross generation of wind turbines. However, accompanying enlargement substructure supporting these larger offshore turbines makes it strongly influenced by effect wave forces. In present study, hybrid is suggested reduce forces composing a multicylinder having different radii near free surface gravity at bottom multicylinder. addition, reaction acting on due very large dead load turbine require firm foundations. This...

In order to design a reliable floating structure, the hydrodynamic motion and structural performance under wave loadings should be reduced with effects of wave-induced hydraulic pressure acting on structure. this study, analytical studies were carried out for optimum type reduce concrete The structure is combined pontoon-type hybrid-type structures, called combination-type verify reducing improving structures. After analysis, six degree motions are investigated fifth periods in shallow...