• Advances in Computational Design
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• v.8 no.4
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• pp.309-325
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• 2023

An innovative inertial reactive armor is being developed through a multi-discipline project. Unlike the well-known explosive or non-explosive reactive armour that uses high-energy explosives or bulging effect, the proposed inertial reactive armour uses active disc elements that is set to rotate rapidly upon impact to effectively deflect and disrupt shaped charges and kinetic energy penetrators. The effectiveness of the proposed armour highly depends on the tangential velocity of the impact point on the rotating disc. However,for a single layer armour with an array of high-speed rotating discs, the tangential velocity is relatively low near the center of the disc and is not available between the gap of the discs. Therefore, it is necessary to configure the armor with double layers to increase the tangential velocity at the point of impact. This paper explores a multi-objective geometry design optimization for the double-layered armor using Nelder-Mead optimization algorithm and integration tools of the python programming language. The optimization objectives include maximizing both average tangential velocity and high tangential velocity areas and minimizing low tangential velocity area. The design parameters include the relative position (translation and rotation) of the disc element between two armor layers. The optimized design results in a significant increase of the average tangential velocity (38%), increase of the high tangential velocity area (71.3%), and decrease of the low tangential velocity area (86.2%) as comparing to the single layer armor.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.311-317
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• 2005

Measurements of the leakage flow in the shrouded cavity were performed in axial compressor cascades at $Re=2.6{\times}10^5$. This paper describes the effects of the leakage flow tangential velocity on kinematics of the leakage flow in the shrouded cavity and consequent overall loss and exit flow turning at stator blade row downstream. Flow data and flow visualization images consistently indicate that leakage flow circumferentially migrates 2, 4 and 5 blade passages in the direction of rotation for ${\upsilon}_y/c=0.09$, 0.35 and 0.45, respectively where ${\upsilon}_y$ is the leakage tangential velocity and c is the mainstream velocity. The leakage flow contracts to a jet across the seal-tooth resulting in an increase in the leakage axial velocity-doubling the leakage axial velocity in upstream cavity compared to that in the downstream cavity. Consequently, two flow regions are distinguished before and after the seal-tooth. As increasing the leakage tangential velocity, the overall loss downstream of stator blade row decreases and the exit flow turning in the range of span. from the hub endwall to 15% increases while the decreases in the flow turning from 15% to 30% span is observed.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.2
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• pp.199-206
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• 2013

In general, radial velocity of a target can be obtained by acquiring doppler frequency shift in case of a doppler radar, or can be obtained by acquiring range rate in case of a pulse radar. Then radial velocity can be converted to tangential velocity using aspect angle or position variation per unit time. These two ways have the same meaning in physically, but result in different uncertainty finally. In this paper, it is described not only the two transformation procedures to calculate tangential velocity from radar measurement data, but also the result of combined uncertainty comparison between these two procedures.

• Journal of the Korean Society of Visualization
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• v.16 no.2
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• pp.45-52
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• 2018

The tangential and axial cyclones were fabricated using a 3D printer and the total collecting efficiency, cut-diameter, and pressure drop characteristics of the two types of cyclones with the same inlet area were investigated experimentally. The results show that the total collecting efficiency tends to increase as the inlet velocity increases. However, at a 20m/s condition of the tangential cyclone, the collected particles were re-entrained to the ascending vortex flow, resulting in a decrease of the total collecting efficiency. In the axial cyclone, the cross-sectional area is designed to increase at the inlet and the velocity is reduced, so that the re-entrainment effect does not appear in this study. The pressure loss of the tangential cyclone was larger than that of the axial cyclone. The cut-diameter tends to decrease with increasing the inlet velocity in two types of cyclones, except for the 20m/s condition of the tangential cyclone.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.6
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• pp.430-437
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• 2003

A conveying fluid cantilever pipe subjected to a uniformly distributed tangential follower force and three moving masses upon it constitute this vibrational system. The influences of the velocities of moving masses, the distance between two moving masses, and the uniformly distributed tangential follower force have been studied on the dynamic behavior of a cantilever pipe system by numerical method. The uniformly distributed tangential follower force is considered within its critical value of a cantilever pipe without moving masses, and three constant velocities and three constant distances between two moving masses are also chosen. When the moving masses exist on pipe, as the velocity of the moving mass and the distributed tangential follower force Increases. the deflection of cantilever pipe conveying fluid is decreased, respectively Increasing of the velocity of fluid flow makes the amplitude of a cantilever pipe conveying fluid decrease. After the moving mass passed upon the pipe, the tip- displacement of a pipe is influenced by the coupling effect between interval and velocity of moving mass and the potential energy change of a cantilever pipe. Increasing of the moving mass make the frequency of the cantilever pipe conveying fluid decrease.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.2
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• pp.179-190
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• 2000

The main object of this study was to investigate experimentally the characteristics of electrostatic cyclone-bag filter with upper tangential inlet in order to overcome the low collection efficiency for the submicron particle and high pressure drop which were main problems of general fabric bag filters. The experiment was carried out for the analysis of collection efficiency and pressure drop of electrostatic cyclone-bag filter comparing to those of fabric bag filter with various experimental parameters such as the inlet velocity(filtration velocity) and applied voltage etc. In the results the upper tangential inlet type showed higher collection efficiency for submicron particles below 2 ${\mu}{\textrm}{m}$ in diameter than that of center inlet and over 99.9% for overall collection efficiency. Pressure drop reduction ratios were shown as 40-50% for the applied voltage 0kV by centrifugal force and 70-90% for 20k V by the centrifuga and electrostatic force with the tangential inlet velocity (12-21m/s)

• Journal of the Korean Society of Safety
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• v.10 no.3
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• pp.42-46
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• 1995

To purpose of this study is to model design and motion analysis of tangential cam mechanism using personal computer system. The CAD(Computer Aided Design) system used in this study was constructed with CPU(Central Processing Unit) 80486, RAM(Random Access Memory) 8M, CGA graphic card. By using developed program for tangential cam mechanism, we designed tangential cam models and analysed displacement, velocity, acceleration of follower.

• Journal of The Korean Astronomical Society
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• v.28 no.1
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• pp.15-30
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• 1995

A velocity inhomogeneity, which is defined as a regional preponderence of either radial or tangential orbits, is searched with a new technique for the Coma cluster of galaxies. It is found within $\~2h^{-1}$ Mpc from the cluster center that the Coma shows conspicuous inhomogeneities in velocity and that the inhomogeneities are real at a $99\%$ level of confidence. Even in the central region (7' - 30' from the center), zones that are dominated by radial and tangential orbits are distinguishable. Defining the cluster's 'equator' as the direction defined by the Coma-A1367 supercluster, tangential orbits dominate the 'polar' zones in the central region. Galaxies that are located in 30'-100' also inhomogeneous in velocity in that the 'polar' zones are mostly radial while the rest is nearly homogeneous. These results indicate that the Coma galaxies are exceedingly more radial in orbit, implying that merging or infalls are either still going on or an earlier virialization is likely to have occurred preferentially near the 'equator'. Incorporating the velocity inhomogeneity into mass estimators, the most appropriate mass is turned out to be $0.4\times10^{15}h^{-1}M_\bigodot(R\;\leq\;0.6h^{-1} Mpc),\;and\;1.0\times10^{15}h^{-1} M_\bigodot(R\;\leq\;2.1h^{-1}Mpc)$. The corresponding mass to blue light ratio on the average is $\~$300h. These estimates are consistent with Merritt (1987) and Hughes (1989) and the MILE is seemed to favour the mass-follows-light models than the uniform spread of dark matter throughout the cluster.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.6
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• pp.1852-1860
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• 1991

A shape design sensitivity of the elastic deformation due to a change of traction boundary condition is presented. The solution of governing equations for a linear elasticity problem is obtained by finite element method and the traction boundary is defined by design variables. The performance functional to be considered involves both the domain and boundary integral. Variations of geometry can be defined as design velocity. Using material derivative concept and adjoint equations, the design sensitivity is derived by Lagrange multiplier method. For a given geometry of a structure, the change of traction boundary is described by the tangential component of the design velocity only. The final result for the shape design sensitivity is formulated as the boundary integral form, the integrand is defined by tangential component of design velocity and first order derivatives of parameters. Numerical implementation of design sensitivity is discussed and is compared with the difference of the actual values.

• Publications of The Korean Astronomical Society
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• v.7 no.1
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• pp.39-50
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• 1992

A velocity inhomogeneity, which is the regional preponderence of either radial or tangential orbits, is searched with the new technique proposed by Kim (1992) for Coma, Hydra I, and Abell 2256 cluster of galaxies. Conspicuous inhomogeneities are found in the Coma and A2256 which X-ray isophotes are indicative for their underlying potentials being ellipitcal in shape, Even in their central regions, zones that are dominated by radial orbits are clearly distinguishable from that of the tangential orbits, and defining the cluster 'equator' as the direction of maximum elongation of the X-ray isophotes, radial orbits dominate along this direction whereas tangential orbits dominate the 'polar' zones. Merger events that are evidenced in X-ray observations occur in the equatorial zones of Coma and A2256, suggesting preponderence of radial orbits in the zones, which is in good agreement with their velocity structures. On the other hand, the inhomogeneity in Hydra I turns out to be insignificant in the central regions and this is just what is expected from a cluster whose X-ray isophotes is nearly circular. The velocity distribution in regions further out, however, shows significant inhomogeneity and this seems to support the previous results that this cluster is likely to have substructures and velocity anisotropy.