• 한국가시화정보학회:학술대회논문집
• /
• 2003.11a
• /
• pp.59-62
• /
• 2003

The near wake behind a sinusoidal cylinder at Re=5200 has been investigated using DPIV system. The velocity fields, streamlines and vorticity contours of the mean flow were compared at the nodal, saddle and middle planes with those of a right circular cylinder. For the sinusoidal cylinder, the vortex core moves downstream and the vortex formation region is expanded in streamwise direction while suppressed in transverse direction at the nodal plane. At the saddle and the middle plane the vortex spread in both streamwise and transverse directions, forming the maximum vortex region at the saddle plane.

• Journal of applied mathematics & informatics
• /
• v.7 no.3
• /
• pp.801-812
• /
• 2000

Two-dimensional slow viscous flow on infinite half-plane past a perpendicular infinite cavity is considered on the basis of the Stokes approximation. Using complex representation of the two-dimensional Stokes flow, the problem is reduced to solving a set of Fredholm integral equations of the second kind. The streamlines and the pressure and vorticity distribution on the wall are numerically determined.

• Journal of computational fluids engineering
• /
• v.5 no.1
• /
• pp.22-26
• /
• 2000

The flow around a ship is complex, especially, at the stern region of a full ship, where highly curved streamlines, hook-shaped iso-velocity contours, and strong secondary flow exist. To resolve this complex flow, an Algebraic Stress Model(ASM) is applied. The calculations are performed for the HSVA Tanker. The results are improved comparing with those of standard k-ε turbulence model, but still show a little difference from the experiments.

• KIEAE Journal
• /
• v.13 no.2
• /
• pp.67-76
• /
• 2013

The purpose of this study is to analyze the accessibility to the place for outdoor exercise. For that, the departure (resident) location of the users of outdoor exercise equipment within 12 parks in Seoul have been investigated. A total of 1,733 people have been surveyed during the two-week period between Aug.2 and Aug. 15 and 815 cases were analyzed. We also investigated demographic characteristics, access method and related factors such as location, climate and visiting time. The results were coded through ArcGis program and the accessibility to each exercise location, difference in regional accessibility and accessibility characteristics in terms of climate and time have been analyzed. The results are as follows: First, visitors to the Han River start from the places further than the visitors to the streamlines. Second, the average moving distance is longer for the users aged under-60 than for the users aged 60 and over to reach the exercise place. And the average moving distance for visitors to the Han River destination is the longest with 748 meters, followed by 203 meters for general parks and 92 meters for streamline parks, respectively. Third, in each non-waterfront parks, the moving distance by users under-60 was longer by about 230 meters than that by users 60 and over. Fourth, exercisers in the weekend travel more by 244 meters than those during the midweek users to reach the exercise place. Fifth, the number of visitors to the Han River increased in the weekend while visitors to the streamlines decreased in the same period. Sixth, the traveling length for bicycle users is three times as much as that for pedestrian visitors. And the departure locations of bicycle users were more widely distributed.

• Journal of Mechanical Science and Technology
• /
• v.15 no.4
• /
• pp.492-499
• /
• 2001

The characteristics of Prand시-Meyer expansion of supersonic flow with condensation along a wavy wall in a channel are investigated by means of experiments and numerical analyses. Experiments are carried out for the case of moist air flow in an intermittent indraft supersonic wind tunnel. The flow fields are visualized by a Schlieren system and the distributions of static pressure along the upper wavy wall are measured by a scanning valve system with pressure transducers. In numerical analyses, the distributions of streamlines, Mach lines, iso-pressure lines, and iso-mass fractions of liquid are obtained by the two-dimensional direct marching method of characteristics. The effects of stagnation temperature, absolute humidity, and attack angle of the upper wavy wall on the generation and the locations of generation and reflection of an oblique shock wave are clarified. Futhermore, it is confirmed that the wavy wall plays an important role in the generation of an oblique shock wave and that the effect of condensation on the flow fields is apparent.

• Proceedings of the KSME Conference
• /
• 2007.05b
• /
• pp.2829-2832
• /
• 2007

In this study, one-way fluid structure interaction analysis(FSI) on wind turbine blade was performed. Both a quantitative fluid analysis on 3-bladed wind turbine and a structural analysis using the surface pressure data resulting from fluid analysis were carried out. Streamlines and angle of attack was easily acquired from analysis results, we showed the inlet velocity that the stall begins to occur. In the structural analysis, structural displacement and maximum stress of the two comparative models was calculated. The location that has maximum stress was found. The pressure difference between back and front part of the blade increases as the inlet velocity increase. The torque and maximum with regard to inlet velocity was also presented.

• Proceedings of the KSME Conference
• /
• 2007.05b
• /
• pp.2851-2856
• /
• 2007

Flow patterns in the presence of two identical nearby circular cylinders at =100 were numerically studied. We considered all possible arrangements of the two circular cylinders in terms of the distance between the two cylinders and the inclination angle with respect to the direction of the main flow. Eight distinct flow patterns were identified based on vorticity contours and streamlines, which are Base-Bleed, Biased-Base-Bleed, Shear- Layer-Reattachment, Induced-Separation, Vortex-Impingement, Flip-Flopping, Modulated Periodic, and Synchronized-Vortex-Shedding. Collecting all the numerical results, we propose a general flow pattern diagram for flows past the two cylinders. The perfect geometrical symmetry implied in the flow configuration allows one to use this diagram to distinguish flow patterns in the presence of two identical circular cylinders arbitrarily positioned in physical space with respect to the main flow direction.

• Journal of Korean Port Research
• /
• v.13 no.1
• /
• pp.175-182
• /
• 1999

The ocean wave is hydrodynamically investigated to get more reliable solution. To improve the computational accuracy more fine grids are used with relatively less computer storage on the free surface. One element of the free surface is discretized into more fine grids because the free-surface waves are much affected by the grid size in the finite difference scheme. Here the multi-grid method is applied to confirm the efficiency for the S103 ship model by solving the Navier-Stokes equation for the turbulent flows. According to the computational result approximately 30% can be improved in the free surface generation, Finally the limiting streamlines show numerical result is similar to the experiment by twin tuft.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.68-71
• /
• 2004

Recently, a great deal of research and development of a fuel cell have been carried out to solve problems on the drain of fossil fuel, air pollution and global warning. In order to improve the efficiency of a fuel cell, it is necessary to clarify the flow in separator. In this study, distributions of velocity flow rate and pressure, and streamlines are examined in detail from numerical analysis with CFD code. In the experiment the distribution of flow rate is measured and flow in the each grooves of the separator is visualized by dye method changing Reynolds number. Furthermore, effects of size of the inlet and outlet manifolds and shape of ribs near the inlet outlet on the distributions of flow and pressure are examined.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.7 no.2
• /
• pp.207-216
• /
• 1995

Flow and heat transfer characteristics of mixed convection heat transfer in a rectangular en-closure with various outlets are numerically investigated. The parameters considered here include Reynolds number, Grashof number and the position of outlet. The results show streamlines, isotherms, Nusselt numbers, velocity and temperature distributions. It has been shown that as Reynolds number increases, the size of cell decreases at Re$\leq$100 and increases at Re>100 for $Gr=10^4$. There is a minimum size of cells at Re=100, $Gr=10^4$. The maximum mean Nusselt number occurs at Re=400, $Gr=10^4$ and one right outlet. The mean Nusselt numbers can be formulated by the correlation equation $Nu=C{\cdot}Gr^a{\cdot}Re^b$.