• 제목/요약/키워드: partition number

검색결과 352건 처리시간 0.033초

정사각형 밀폐공간내에서 수평격판에 의한 자연대류의 진동현상 (Oscillatory Motion of Natural Convection in a Square Enclosure with a Horizontal Partition)

  • 김점수;정인기;송동주
    • 설비공학논문집
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    • 제5권4호
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    • pp.285-294
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    • 1993
  • An oscillatory motion of natural convection in a two-dimensional square enclosure fitted with a horizontal partition is investigated numerically. The enclosure was composed of the lower hot and the upper cold horizontal walls and the adiabatic vertical walls, and a partition was positioned perpendicularly at the mid-height of one vertical insulated wall. The governing equations are solved by using the finite element method with Galerkin method. The computations were carried out with the variations of the partition length and Rayleigh number based on the temperature difference between two horizontal walls and the enclosure height with water(Pr=4.95). As the results, an oscillatory motion of natural convection has perfectly shown the periodicity with the decrease of Rayleigh number, and the stability was reduced to a chaotic state with the increase of Rayleigh number. The period of oscillation gets shorten with the decrease of the partition length and the increase of Rayleigh number. The frequency of oscillation obtained by the variations of stream function is more similar to the experimental results than that of the average Nusselt number. The stability of oscillation grows worse with the increase of Rayleigh number. The transition Rayleigh number for the chaos is gradually decreased with the increase of the partition length.

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격판을 가진 밀폐공간내의 자연대류 열전달에 공간 및 격판의 경사가 미치는 영향 (Effects of Inclination of Enclosure and Partition on Natural Convective Heat Transfer in a Partitioned Enclosure)

  • 정인기;송동주;김점수
    • 설비공학논문집
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    • 제6권3호
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    • pp.302-314
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    • 1994
  • The effects of the inclination of enclosure and partition on natural convective flow and heat transfer were investigated numerically. The enclosure was composed of the lower hot and the upper cold horizontal walls and the adiabatic vertical walls, and a partition was positioned perpendicularly at the mid-height of one vertical insulated wall. The governing equations are solved by using the finite element method with Galerkin method. The computations were performed with the variations of the partition length and Rayleigh number based on the temperature difference between two horizontal walls and the enclosure height with water(Pr=4.95). The effects of the inclination angle of enclosure and partition on the heat transfer within an enclosure were also studied. As the results, the increase of the inclination angle of enclosure rapidly raised the heat transfer rate, while the inclination angle for the maximum Nusselt number was retarded with the increase of the partition length and the decrease of the heat transfer rate became larger in proportion to the increase of the partition length. The Nusselt number obtained by the inclination of partition was smaller than that of the inclination of enclosure. However, the difference of the heat transfer rates was considerably decreased at the longer partition lengths and the trends for the variation of the average Nusselt number were more similar with that of the inclination of enclosure. The upward oriented partition increases the convective heat transfer distinctly in contrast to that of the inclination of enclosure as the partition length increases.

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수평격판을 갖는 정사각형 밀폐공간내에서 자연대류 유동 및 열전달 (Natural Convective Flow and Heat Transfer in a Square Enclosure with a Horizontal Partition)

  • 정인기;김점수;송동주
    • 대한기계학회논문집
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    • 제17권9호
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    • pp.2304-2314
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    • 1993
  • Natural convective flow and heat transfer in a two-dimensional square enclosure fitted with a horizontal partition are investigated numerically. The enclosure was composed of the lower hot and the upper cold horizontal walls and the adiabatic vertical walls, and a partition was situated perpendicularly at the one vertical insulated wall. The governing equations are solved by using the finite element method with Galerkin method. The computations were carried out with the variations of length, position and thermal conductivity of the partition, and Rayleigh number based on the temperature difference between two horizontal walls and the enclosure height with water(Pr=4.95). As the results, an oscillatory motion of natural convection is resulted in a sudden rise of overall heat transfer, but the increase of length of partition is significantly restrained the increase of Nusselt number. The maximum heat transfer was shown just before the transition of the direction of oscillating flow. An oscillatory motion of flow was perfectly shown the stability with the decrease of the length of partition and Rayleigh number. Also, the heat transfer was raised with the increase of the thermal conductivity in proportion to the increase of the length of partition. The stability and oscillation of flow are affected by the position of partition.

제어판이 부착된 수평격판에 의해 분리되는 밀폐공간내의 난류 자연대류 열전달 특성 (Turbulent natural convective heat transfer charateristics in a square enclosure with control plates attached at the horifontal partition)

  • 김점수
    • 설비공학논문집
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    • 제12권2호
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    • pp.150-160
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    • 2000
  • Turbulent natural convective flow and heat transfer in a square enclosure with horizontal partition are investigated numerically. The enclosure is composed of a lower hot and a upper cold horizontal walls and adiabatic vertical walls. Partitions carried with the upward, downward, and both control plates are attached perpendicularly to the one of the vertical insulated walls, respectively. The low Reynolds number $k-\varepsilon$ model is adopted to calculate the turbulent thermal convection. The governing equations are solved by using the finite element method with Galerkin method. The computations have been carried out by varying the length of partition, the position of control plates, and the Rayleigh number based on the temperature difference between two horizontal walls and the enclosure height for water(Pr=4.95). When the control plates are attached at the edge of partition, the stability of oscillating flow grows wrose with the increase of Rayleigh number and the partition length. The heat transfer rate has been reducer than that of no control plate due to the restraint of control plates with the increase of Rayleigh number.

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ON PARTITION CONGRUENCES FOR OVERCUBIC PARTITION PAIRS

  • Kim, Byung-Chan
    • 대한수학회논문집
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    • 제27권3호
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    • pp.477-482
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    • 2012
  • In this note, we investigate partition congruences for a certain type of partition function, which is named as the overcubic partition pairs in light of the literature. Let $\bar{cp}(n)$ be the number of overcubic partition pairs. Then we will prove the following congruences: $$\bar{cp}(8n+7){\equiv}0(mod\;64)\;and\;\bar{cp}(9m+3){\equiv}0(mod\;3)$$.

ON AN INVOLUTION ON PARTITIONS WITH CRANK 0

  • Kim, Byungchan
    • East Asian mathematical journal
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    • 제35권1호
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    • pp.9-15
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    • 2019
  • Kaavya introduce an involution on the set of partitions with crank 0 and studied the number of partitions of n which are invariant under Kaavya's involution. If a partition ${\lambda}$ with crank 0 is invariant under her involution, we say ${\lambda}$ is a self-conjugate partition with crank 0. We prove that the number of such partitions of n is equal to the number of partitions with rank 0 which are invariant under the usual partition conjugation. We also study arithmetic properties of such partitions and their q-theoretic implication.

Design of Hard Partition-based Non-Fuzzy Neural Networks

  • Park, Keon-Jun;Kwon, Jae-Hyun;Kim, Yong-Kab
    • International journal of advanced smart convergence
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    • 제1권2호
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    • pp.30-33
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    • 2012
  • This paper propose a new design of fuzzy neural networks based on hard partition to generate the rules of the networks. For this we use hard c-means (HCM) clustering algorithm. The premise part of the rules of the proposed networks is realized with the aid of the hard partition of input space generated by HCM clustering algorithm. The consequence part of the rule is represented by polynomial functions. And the coefficients of the polynomial functions are learned by BP algorithm. The number of the hard partition of input space equals the number of clusters and the individual partitioned spaces indicate the rules of the networks. Due to these characteristics, we may alleviate the problem of the curse of dimensionality. The proposed networks are evaluated with the use of numerical experimentation.

수평격판을 갖는 4각형 밀폐공간내에서 자연대류의 진동유동 (Oscillatory Motion of Natural Convective Flow in Partially Divided Square Enclosure)

  • 김점수;정인기;송동주
    • 대한기계학회논문집
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    • 제16권10호
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    • pp.1963-1970
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    • 1992
  • 본 연구에서는 Fig.1에 나타낸 정 등의 모델을 사용하여 공간내의 자연대류 유동을 수치적으로 해석하고 실험결과와 비교하여 수평격판에 의해서 발생하는 진동유 동의 특성을 규명하고자 한다. 본 수치해석에서는 물(Pr=4.95)을 내부유체로 하여 Rayleigh수, 공간의 폭에 대한 격판길이(L/W)및 격판의 열전도율의 변화가 자연대류 진동유동에 미치는 영향을 밝히고, 밀폐공간의 경사에 의해 진동유동이 사라지는 각 도, 즉 천이 경사각도를 찾아 내고자 한다. 이러한 유동특성을 파악하기 위하여 본 연구에서는 지배방정식을 Galerkin method를 사용한 2차원 유한요소법(FEM)으로 수치 해석하였다.

가변 격판을 갖는 사각공간 내의 혼합대류에 대한 실험과 수치해석 (An Experiment and Numerical Analysis of Mixed Convection in a Rectangular Space with Variable Partition)

  • 이광성;신재호;이중섭;정한식;정효민
    • 설비공학논문집
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    • 제13권12호
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    • pp.1230-1235
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    • 2001
  • The laminar convection heat transfer in a ventilated space with various horizontal partitions was studied numerically and experimentally. The experimental results by holographic interferometer showed good agreements with the numerical results. For the numerical study, the governing equations were solved by using a finite volume method for $46.6\leqRe\leq1332,\;1460\leqGr\leql1585$, Pr=0.71 and the variations of partition lengths. The isotherms and velocity vectors have been represented for various parameters. As the length of partition increases, the convection heat transfer decreases. Based on the numerical data, a correlation was obtained for the dimensionless mean Nusselt number in terms of $Gr/Re^2$. In the region of $Gr/Re^2$<1, the mean Nusselt number was very small, but in the region of $Gr/Re^2\geq1$, the mean Nusselt number was constant.

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입력 공간 분할에 따른 뉴로-퍼지 시스템과 응용 (Neuro-Fuzzy System and Its Application by Input Space Partition Methods)

  • 곽근창;유정웅
    • 한국지능시스템학회:학술대회논문집
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    • 한국퍼지및지능시스템학회 1998년도 추계학술대회 학술발표 논문집
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    • pp.433-439
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    • 1998
  • In this paper, we present an approach to the structure identification based on the input space partition methods and to the parameter identification by hybrid learning method in neuro-fuzzy system. The structure identification can automatically estimate the number of membership function and fuzzy rule using grid partition, tree partition, scatter partition from numerical input-output data. And then the parameter identification is carried out by the hybrid learning scheme using back-propagation and least squares estimate. Finally, we sill show its usefulness for neuro-fuzzy modeling to truck backer-upper control.

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