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Kim, Moon-Sang;Jeon, Byung-Woo;Kim, Yong-Nyun;Kwon, Hyeok-Bin;Lee, Dong-Ho
- Journal of Mechanical Science and Technology
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- v.15 no.5
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- pp.671-680
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- 2001
Boundary condition is one of the major factors to influence the numerical stability and solution accuracy in numerical analysis. One of the most important physical boundary conditions in the flowfield analysis is the wall boundary condition imposed on the body surface. To solve a two-dimensional Euler equation, totally four numerical wall boundary conditions should be prescribed. Two of them are supplied by the flow tangency condition. The other two conditions, therefore, should be prepared additionally in a suitable way. In this paper, four different sets of wall boundary conditions are proposed and then applied to solve high-speed flowfields around a quarter circle geometry. A two-dimensional compressible Euler solver is prepared based on the finite volume method. This solver hires three different upwind schemes; Steger-Warmings flux vector splitting, Roes flux difference splitting, and Lious advection upstream splitting method. It is found that the way to specify the additional numerical wall boundary conditions strongly affects the overall stability and accuracy of the upwind schemes in high-speed flow calculation. The optimal wall boundary conditions should be also chosen very carefully depending on the numerical schemes used to solve the problem.
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Chung, Chang-Joo;Chung, Sun-Ok;Cho, Seong-In;Chang, Young-Chang;Park, Yeong-Soo
- Proceedings of the Korean Society for Agricultural Machinery Conference
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- 1996.06c
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- pp.519-527
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- 1996
Most operation related to the application granular agrochemicals in korea are manual and labour consuming. As a multipurpose granular applicator, a pneumatic granular applicator that can be attached to conventional ride -on machines for paddy field was designed in this study. Experiments and simulations were carried out for determine in the design factors with one fertilizer (DongBu 21-17-17) and one pesticide (SamKong Ivi). The maximum terminal velocity of granular chemicals was estimated as 14.2m/s. A better distribution pattern was obtained at the diffuser having only deflectors without dividing guides. The diffuser spacing 1.0m for the fertilizer and the diffuser spacing 0.8m for the pesticide at the boom height over 0.80m were acceptable for the uniform distribution. In the case that the forward speed of ride-on machines was 0.7m/s, the groove opening and the roller speed of the selected metering device were13mm -15mm at 2 rps for the fertilizer, and 9 mm-11mm at 0.25rps or the pesticide. This study suggested a method of developing a pneumatic applicator for granular agrochemicals.
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;;M.J. Delwichi
- Journal of Biosystems Engineering
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- v.26 no.2
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- pp.189-196
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- 2001
바이오 센서 개발에 대한 주 동기는 건강보호 산업이었지만, 최근의 연구 동향은 농업 및 생물 생산 시스템 분야로 확산되고 있다. 바이오 센서의 본질과 기능에 관한 일반적인 논의가 간단히 제시되었고, 제자들에 의해 연구된 및 종류의 바이오 센서 예와 그들의 적용에 대해 소개하였다.
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