• 한국해양공학회:학술대회논문집
• /
• 한국해양공학회 2004년도 학술대회지
• /
• pp.90-95
• /
• 2004

During the past 50 years methods for predicting wave overtopping of coastal structures have coastal structures have continuously been developed Wave overtopping is one of the most important processes for the design of seawalls. The term 'wave overtopping' is used here to refer to the processes where waves hit a sloping structure run up the slope and, if the crest level of the slope is lower than the highest run up level, overtop the structure. Wave overtopping is dependent on the processes associated with breaking wave. The Numerical model is based on Navier-Stokes equation and Marker-Density Function of method for nonlinear free-surface flow by Miyata & Park(1995). The influence of how the slopes of seawalls, wave type and crest freeboard affect overtopping discharges has been investigated. The research of study using the new development nonlinear free-surface flow numerical model SOLA-VOF are presented.

• 대한조선학회논문집
• /
• 제51권5호
• /
• pp.419-428
• /
• 2014

This paper presents a numerical simulation method for the flow around advancing ships in regular waves by using a rectilinear grid system. Because the grid lines do not consist with body surface in the rectilinear grid system, the body geometries are defined by the interaction points of those grid lines and the body surface. For the satisfaction of body boundary conditions, no-slip and divergence free conditions are imposed on the body surface and body boundary cells, respectively. Meanwhile, free surface is defined with the modified marker density method. The pressure on the free surface is determined to make the pressure gradient terms of the governing equations continuous, and the velocity around the free surface is calculated with the pressure on the free surface. To validate the present numerical method, a vortex induced vibration (VIV) phenomenon and flows around an advancing Wigley III ship model in various regular waves are simulated, and the results are compared with existing and corresponding research data. Also, to check the applicability to practical ship model, flows around KRISO Container Ship (KCS) model advancing in calm water are numerically simulated. On the simulations, the trim and the sinkage are set free to compare the running attitude with some other experimental data. Moreover, flows around the KCS model in regular waves are also simulated.

• 대한조선학회논문집
• /
• 제47권5호
• /
• pp.671-679
• /
• 2010

This paper introduces a new hull form design method for the bow of a full ship, by actively applying the relation between the fore-body hull form and its wave resistance characteristics. For the hull form design, the Series 60($C_B=0.8$) hull is chosen as the parent ship, and Kracht's charts are used to determine the parameters of the bulbous bow in the early stages of hull form design. Several hull forms have been tested in order to obtain enough hull form variations with various bow shapes and design parameters in the search of the best design. In order to investigate the resistance characteristics of the designed hull forms, numerical simulations with corresponding model tests have been rigorously performed. For the numerical simulations, the Marker-density method is employed to track the nonlinear phenomena of the free surface(program IUBW). Model tests have also been performed to achieve an improved research performance using the designed hulls. Both numerical and experimental results show that the wave resistance of the hull forms can be effectively diminished if the bows are designed using the method introduced in this research. It is also expected that this research can facilitate better productivity in hull form design, especially at the preliminary design stage of a full ship type vessel.

• 약학회지
• /
• 제49권1호
• /
• pp.44-50
• /
• 2005

The purpose of this study was to investigate the relationship between Trp64Arg polymorphism in the ${\beta}_3$-adrenergic receptor gene and complex phenotypes such as blood pressure, body compositions and bone parameters in young men about 20 years, and to collect the fundamental data in designing the exercise program. Eighty healthy young men including 41 controls and 39 athletes were recruited, Trp64Arg polymorphism in the ${\beta}_3$-adrenergic receptor gene was genotyped by PCR-RFLP method. By association study, there were no significance in genotype and allele frequencies of Trp64Arg polymorphism in the ${\beta}_3$-adrenergic receptor gene between controls and athletes, respectively (p>0.05). When the relationship between physiological parameters and Trp64Arg polymorphism in the ${\beta}_3$-adrenergic receptor gene was tested, this polymorphism was significantly associated with 3th lumber and left femoral neck Z-score values in controls (p<0.05), but these associations were not detected in athletic groups (p>0.05). It is likely that Trp64Arg polymorphism in the ${\beta}_3$-adrenergic receptor gene is a genetic marker for the bone mineral density index in young men, but environmental factors such as exercise modify the significant effect of this polymorphism. Thus, our results suggest that Trp64Arg polymorphism in the ${\beta}_3$-adrenergic receptor gene may be applicable as a predictive marker for osteoporosis in Korean young men, and regular exercise may prevent the disadventageous effect of this polymorphism for bone mineral density in male athletic group.

• 한국해양공학회지
• /
• 제17권6호
• /
• pp.7-15
• /
• 2003

A Digital Wave Tank simulation technique, based on a finite-difference method and a modified marker-and-cell (MAC) algorithm, is applied in order to investigate the characteristics of nonlinear Tsunami propagations and their interactions with a 2D sloping beach, Ohkushiri Island, and to predict maximum wove run-up around the island. The Navier-Stokes (NS) and continuity equation are governed in the computational domain, and the boundary values are updated at each time step, by a finite-difference time-marching scheme in the frame of the rectangular coordinate system. The fully nonlinear, kinematic, free-surface condition is satisfied by the modified marker-density function technique. The near shore Tsunami is assumed to be a solitary wave, and is generated from the numerical wave-maker in the developed Digital Wave Tank. The simulation results are compared with the experiments and other numerical methods, based on the shallow-water wave theory.

• 한국전산유체공학회지
• /
• 제11권4호
• /
• pp.90-100
• /
• 2006

A digital wave tank (DWT) simulation technique has been developed by authors to investigate the interactions of fully nonlinear waves with 3D marine structures. A finite-difference/volume method and a modified marker-and-cell (MAC) algorithm have been used, which are based on the Navier-Stokes (NS) and continuity equations. The fully nonlinear kinematic free-surface condition is implemented by the marker-density function (MDF) technique or the Level-Set (LS) technique developed for one or two fluid layers. In this paper, some applications for various engineering problems with free-surface are introduced and discussed. It includes numerical simulation of marine environments by simulation equipments, fully nonlinear wave motions around offshore structures, nonlinear ship waves, ship motions in waves and marine flow simulation with free-surface. From the presented simulations, it seems that the developed DWT simulation technique can handle various engineering problems with free-surface and reliably predict hydrodynamic features due to the fully-nonlinear wave motions interacting with such marine structures.

• 한국해양공학회:학술대회논문집
• /
• 한국해양공학회 2003년도 춘계학술대회 논문집
• /
• pp.231-239
• /
• 2003

A Digital Wave Tank simulation technique based on a finite-difference method and a modified marker-and-cell (MAC) algorithm is applied to investigate the characteristics of nonlinear Tsunami propagations and their interactions with a 2D sloping beach and Ohkushiri island, and to predict maximum wave run-up around the island. The Navier-Stokes (NS) and continuity equation are governed in the computational domain and the boundary values updated at each time step by a finite-difference time-marching scheme in the frame of rectangular coordinate system. The fully nonlinear kinematic free-surface condition is satisfied by the modified marker-density function technique. The Nearshore Tsunami is assumed to be a solitary wave and generated from the numerical wavemaker in the developed Digital Wave Tank. The simulation results are compared with the experiments and other numerical methods based on the shallow-water wave theory.

• 대한조선학회논문집
• /
• 제45권2호
• /
• pp.124-131
• /
• 2008

This paper presents the analysis of resistance performance and bow waves for the resistance-minimized hull form of small fishing boat by using numerical simulations and model tests. The resistance-minimized hull form is developed from an original hull form which is selected from existing small fisher boats in our country. In order to estimate the resistance performance for the original and the developed hull form, several numerical simulations and model tests are carried out. Marker and Cell(MAC) method and Marker-Density method are adopted to simulate the free-surface bow waves around advancing hull surface. The results of numerical simulations are compared with the model tests in towing tank. The results show that the resistance performance of the resistance-minimized hull form is improved than that of the original hull form. The results of this study will be a good guide to the hull form development of small fishing boats in future.

• 대한조선학회논문집
• /
• 제54권6호
• /
• pp.492-500
• /
• 2017

In the study, numerical simulation on the greenwater impact load of free surface offshore structure in the regular waves using fixed cartesian grid system and Modified Marker-Density (MMD) method were carried out and the results were reviewed. In order to compare numerical simulation and experimental results, the FPSO with the scale ratio of 1/100 model ship with fixed rectangular deck was selected and turbulence characteristic of the flow was considered by applying the Sub-Grid Scale (SGS) in laminar flow. As a result, it is reviewed how the greenwater impact load inflowed from bow in regular headsea wave influence the flow on the deck and the flow characteristic by numerical simulation and the experiment results were compared and reviewed. Based on this study, it would be useful to numerically study the effect of greenwater on offshore structure.

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권1호
• /
• pp.583-587
• /
• 2013

This study aimed to investigate tumor microvessel density (MVD) and lymphatic vessel density (LVD) using the Chalkley method as predictive markers for the risk of axillary lymph node metastasis and their relationship to other clinicopathological parameters in primary breast cancer cases. Forty two node-positive and eighty node-negative breast cancers were immunostained for CD34 and D2-40. MVD and LVD were counted by the Chalkley method at x400 magnification. There was a positive significant correlation of the MVD with the tumor size, coexisting ductal carcinoma in situ (DCIS) and lymph node metastases (P<0.05). In multivariate analysis, the MVD (2.86-4: OR 5.87 95%CI 1.05-32; >4: OR 20.03 95%CI 3.47-115.55), lymphovascular invasion (OR 3.46, 95% CI 1.13-10.58), and associated DCIS (OR 3.1, 95%CI 1.04-9.23) independently predicted axillary lymph node metastasis. There was no significant relationship between LVD and axillary lymph node metastasis. However, D2-40 was a good lymphatic vessel marker to enhance the detection of lymphatic invasion compared to H and E staining. In conclusion, MVD by the Chalkley method, lymphovascular invasion and associated DCIS can be additional predictive factors for axillary lymph node metastases in breast cancer. No relationship was identified between LVD and clinicopathological variables, including axillary lymph node metastasis.