• Transactions of Materials Processing
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• v.1 no.1
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• pp.20-32
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• 1992

This paper describes some research of Computer-Aided Process Planning and Die Design of Hot Forging for axisymmetric parts produced by the press. An approach to the system is based on knowledge based system. The system has been written in AutoLisp with personal computer. Knowledges for process planning & die design are extracted from the plasticity theories, handbooks, relevent references and empirical know-how of field experts in hot forging companies. The developed system is composed of five main modules, such as input module, process planning module, die design module, flow simulation module and output module which are used independently or in all. The final output is generated in graphic from. The developed system which aids designer provides powerful capabilities for process planning and die design of hot forging. This system also provides approximate flow pattern.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.1
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• pp.10-16
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• 2000

Spatially resolved liquid volume fractions from a set of line-of-sight laser diffraction measurements for axisymmetric sprays generated from a pintle-type gasoline injector have been tomographically reconstructed by Abel transformation, Fourier transformation and onion peeling method. Spatially resolved liquid volume fractions classified into 32 size groups were translated characteristics of SI engine fuel sprays. These data were also obtained from the phase Doppler measurements for the same sprays. The comparison between laser deffraction measurements and transformation reconstructs more reasonable spatially resolved characteristics for axisymmetric sprays as well as for asymmetric sprays.

• International Journal of Aeronautical and Space Sciences
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• v.9 no.1
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• pp.1-30
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• 2008

When the stagnation temperature of a perfect gas increases, the specific heats and their ratio do not remain constant any more and start to vary with this temperature. The gas remains perfect; its state equation remains always valid, except, it is named in more by calorically imperfect gas. The aim of this work is to trace the profiles of the supersonic axisymmetric Minimum Length Nozzle to have a uniform and parallel flow at the exit section, when the stagnation temperature is taken into account, lower than the dissociation threshold of the molecules, and to have for each exit Mach number and stagnation temperature shape of nozzle. The method of characteristics is used with the algorithm of the second order finite differences method. The form of the nozzle has a point of deflection and an initial angle of expansion. The comparison is made with the calorically perfect gas. The application is for air.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.04a
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• pp.79-82
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• 2002

Induction heating is widely used in today's industry, in operations such as metal hardening, preheating for forging operations, melting or cooking. In this paper, it was presented the magneto-thermal analysis of an induction heating jar(IH-JAR) with the material value of the stainless and the aluminum for efficient design. The magnetic field intensity inside the axisymmetric shaped cooker was analyzed using three-dimensional axisymmetric finite element method(FEM) and the effectual heat source was obtained by ohmic losses from eddy currents induced in the jar. The heat was calculated using the heat source and heating equation. Also, it was represented the temperature characteristics of the IH-JAR according to time and relative permeability in stainless parts and in aluminum parts.

• Bulletin of the Society of Naval Architects of Korea
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• v.20 no.2
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• pp.27-36
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• 1983

This paper presents numerical results of the added mass and damping coefficients of vertical axisymmetric bodies on or under the free surface. Also computed are the excitation forces on these bodies due to an incident regular wave system. The numerical scheme employs a localized finite-element method, which is based on the theory of the calculus of variations. The excitation forces and moments on a submerged half-spheroid lying on the bottom are computed and compared with the results obtained by others. he agreement is good. Several specific types of floating vertical axisymmetric platforms are considered for ten different wave lengths, in connection with the design of an ocean-thermal-energy converter platform. The added mass and damping coefficient, as well as the excitations, are presented. It is shown that simple strip theory gives a good approximation of the sway(and pitch) added mass for a disc platform having a long circular cylinder.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1997.10a
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• pp.87-94
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• 1997

The circular plate resting on Boussinesq's half-space model under axisymmetric loading is studied by a finite element procedure to evaluate the distribution of contact pressure between plate and elastic half-space. The displacement of half-space due to axisymmetric surface loading can be evaluated by double integration of Boussinesq's solution. On that case the analytical integration can be executed for the radial direction but the analytical integration for the circumferential direction is impossible and the numerical integration should be considered. With the radial integration we can get non-dimensional function. Then the numerical integration for the formula is executed for the circumferential direction and the results are approximated 5th order Polynomials by using the least square method. With these 5th order approximate formula, the flexibility matrix of half-space is constructed as the coefficient matrix of nodal contact pressure by the finite element procedures. Iteration procedures are attempted by using this method to determine the separated region.

• Transactions of Materials Processing
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• v.5 no.1
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• pp.27-36
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• 1996

In this paper a computer-aided design system for axisymmetric deep drawing process will be described. An approach to the system is based on the knowledge based system. The system has been written in AutoLISP with personal computer. The system is composed of four main modules such as input geometrical design test & rectification and user modification. the system which aids designer provides powerful capabilities for the design of axisymmetric deep drawing process.

• Bulletin of the Society of Naval Architects of Korea
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• v.23 no.1
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• pp.13-22
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• 1986

Axisymmetric turbulent thick boundary layers on a rotating body of revolution are calculated numerically in the paper. Richardson number is introduced to the mixing length to take account of swirl effects on Reynolds stresses. Interactions of the boundary layer and the external potential flow are included by adding the displacement thickness of boundary layers on the original body. Pressure distributions on the body surface are estimated by integrating normal momentum equation across the boundary layer. A model is designed and tested in the wind tunnel. Mean velocities are measured. Through the present study, swirl effects on the thick axisymmetric boundary layer development are considerable in comparison with those of non-totating cases. Rotational motion generally increase boundary layer thickness, axial skin friction coefficients, and form drags. Circumferential flow can be reversed to induce negative skin friction when the section area is reduced.

• Structural Engineering and Mechanics
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• v.61 no.1
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• pp.143-160
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• 2017

The paper studies the attenuation of the axisymmetric longitudinal waves propagating in the bi-layered hollow cylinder made of linear viscoelastic materials. Investigations are made by utilizing the exact equations of motion of the theory of viscoelasticity. The dispersion equation is obtained for an arbitrary type of hereditary operator of the materials of the constituents and a solution algorithm is developed for obtaining numerical results on the attenuation of the waves under consideration. Specific numerical results are presented and discussed for the case where the viscoelasticity of the materials is described through fractional-exponential operators by Rabotnov. In particular, how the rheological parameters influence the attenuation of the axisymmetric longitudinal waves propagating in the cylinder under consideration, is established.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1749-1754
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• 2004

In order to measure non-intrusively velocity profile in liquid metal flow, a modified electromagnetic flowmeter was designed, which was based on electromagnetic tomography technique. Under the assumption that flow is fully-developed, axisymmetric and rectilinear, the velocity profile was reconstructed after the flowmeter equation, the first kind of Fredholm integration equation, was linearized. In reconstruction process Tikhonov regularization method with regularization parameter was used. The reconstructed velocity profile had the nearly same as turbulent flow profile which was approximately represented as log law. In addition, flowmeter output for a fixed magnet rotation angle was linearly proportional to flow rate. When magnet rotation angle was $54^{\circ}$, axisymmetric weight function was nearly uniform so that the flowmeter gives a constant signal for any fully-developed, axisymmetric and rectilinear profile with a constant flow rate.