• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.8
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• pp.2681-2692
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• 1996

The finite-volume method for radiation in a three-dimensional non-orthogonal gas turbine combustion chamber with absorbing, emitting and anisotropically scattering medium is presented. The governing radiative transfer equation and its discretization equation using the step scheme are examined, while geometric relations which transform the Cartesian coordinate to a general body-fitted coordinate are provided to close the finite-volume formulation. The scattering phase function is modeled by a Legendre polynomial series. After a benchmark solution for three-dimensional rectangular combustor is obtained to validate the present formulation, a problem in three-dimensional non-orthogonal gas turbine combustor is investigated by changing such parameters as scattering albedo, scattering phase function and optical thickness. Heat flux in case of isotropic scattering is the same as that of non-scattering with specified heat generation in the medium. Forward scattering is found to produce higher radiative heat flux at hot and cold wall than backward scattering and optical thickness is also shown to play an important role in the problem. Results show that finite-volume method for radiation works well in orthogonal and non-orthogonal systems.

• Transactions of the Korean hydrogen and new energy society
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• v.24 no.5
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• pp.451-460
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• 2013

In a direct coal fuel cell (DCFC) system, it is essential to identify volume fraction of coal suspended in electrolyte melt in order to control its dispersion and fluidity. This requirement is compelling especially at anode channel where hot slurry is likely to flow at low velocity. In this study, light scattering techniques were employed to measure the volume fraction for a pulverized coal suspension with relatively high absorption coefficient. The particle size, scattering angle, and volume fraction were varied to evaluate their effects on the scattering behavior as well as scattering regime. The larger coal size and smaller forward scattering angle could provide a shift to more favorable scattering regime, i.e., independent scattering, where interferences of light scattering from one particle with others are suppressed.

• Coupled systems mechanics
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• v.1 no.2
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• pp.183-204
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• 2012

A method for the analysis of wave scattering in 3-D elastic full space is developed by means of the coupled boundary-volume integral equation, which takes into account the effects of both the boundary of inclusions and the uctuation of the wave field. The wavenumber domain formulation is used to construct the Krylov subspace by means of FFT. In order to achieve the wavenumber domain formulation, the boundary-volume integral equation is transformed into the volume integral equation. The formulation is also focused on this transform and its numerical implementation. Several numerical results clarify the accuracy and effectiveness of the present method for scattering analysis.

• Bulletin of the Korean Chemical Society
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• v.33 no.3
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• pp.1071-1074
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• 2012

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.1
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• pp.135-140
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• 2003

The convergence of finite volume method (FVM) or discrete ordinate method (DOM) is known to degrade for optical thickness greater than unity and large scattering albedo. The present article presents a convergence acceleration procedure for the FVM based on a full approximation storage (FAS) multigrid method. Among a variety of multigrid cycles, the V-cycle is used and the full multigrid algorithm (FMG) is applied to an analysis of radiation in irregular two-dimensional geometry. Solution convergence is discussed for the several cases of various optical thickness and scattering albedo. At small scattering albedo and optical thickness, there is no advantage to using the multigrid method for calculation CPU time. For large scattering albedo greater than 0.5 and optical thickness greater than unity, however, the multigrid method improves the convergence and the solution is rapidly obtained.

• Korean Journal of Remote Sensing
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• v.4 no.1
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• pp.1-16
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• 1988

Multiyear ice is quite thick in general, and it needs to be distinguished from thinner types of ice because it represents a severe navigational hazard. Here, models are described for the radar backscatter from multiyear sea ice, based on simple scattering layers. Under cold conditions, the radiative transfer volume-scatter model can describe the backscattering from multiyear ice for frequencies higher than about X-band, while the surface scattering contribution has to be included for lower frequencies. A simple semi-empirical model is shown to be a good approximation to the radiative transfer model in describing the volume scattering from multiyear ice.

• 한국연소학회:학술대회논문집
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• 2000.05a
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• pp.16-25
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• 2000

The differential diffusion of two species in jet is considered. The direct photo images of $H_{2}/SF_{6}$ flame are taken and the non-react jets of $H_{2}/SF_{6}$ mixture are visualized with Rayleigh scattering method. The structures of Dual flame are found in the photography. As the volume fraction of $H_2$ in mixture is increased, the flame at side is long and as the volume fraction of $SF_{6}$ in mixture is increased, the flame at center is long. This phenomena are deduced from the non-react mixture using Rayleigh scattering method. Result show that the volume fraction in the mixture is important in differential diffusion.

• KIPS Transactions on Software and Data Engineering
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• v.5 no.12
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• pp.677-684
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• 2016

For realistic rendering volume to calculate the light effects as well as the shade is essential. In order to produce the high quality of the resulting image, it is necessary to represent a global illumination, and it should be considered an indirect effect of the direct impact and scattering of light. It requires a lot of resources in order to perform this operation and, in particular, is very expensive when large amounts of data to be rendered as a volume data is consumed. In this paper, we generate a scatterer template according to the physical laws for each material. Considering that each object having material property stores photons of the template based on the Lambert illumination model. When the volume rendering in this paper, using the photon is stored in the template, based on the voxel to be sampled within the examination volume occluded, and it represents the global illumination of the scattering. Because the materials produced by the template requires a less resource only if comprised of a complex material, a simple operation can be expressed within the scattering volume at a low cost through.

• Journal of the Korea Computer Graphics Society
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• v.16 no.1
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• pp.9-20
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• 2010

In order to visualize participating media in 3D space, they usually calculate the incoming radiance by subdividing the ray path into small subintervals, and accumulating their respective light energy due to direct illumination, scattering, absorption, and emission. Among these light phenomena, scattering behaves in very complicated manner in 3D space, often requiring a great deal of simulation efforts. To effectively simulate the light scattering effect, several approximation techniques have been proposed. Volume photon mapping takes a simple approach where the light scattering phenomenon is represented in volume photon map through a stochastic simulation, and the stored information is explored in the rendering stage. While effective, this method has a problem that the number of necessary photons increases very fast when a higher variance reduction is needed. In an attempt to resolve such problem, we propose a different approach for rendering particle-based volume data where kernel smoothing, one of several density estimation methods, is explored to represent and reconstruct the light in-scattering effect. The effectiveness of the presented technique is demonstrated with several examples of volume data.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.4
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• pp.7-13
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• 2007

Effects of pulp type, refining and filler type on the pore characteristics and physical properties of paper were investigated. HwBKP, SwBKP and BCTMP are used to study the effect of pulp type in this study. The effects of each filler (PCC, GCC and talc) and the combination of PCC/GCC were also studied. Highest bulk, pore volume and light scattering are obtained from BCTMP and PCC. It was found that the pore size and pore volume are important in light scattering in paper structure. It was found that PCC was the most effective filler for the improvement of the bulk and light scattering because of the increase in pore volume which can scatter light, but the increase of PCC content was not so effective in the improvement of bulk.