• Title/Summary/Keyword: Non dimensional Variables

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The Accuracy of the Non-continuous I Test for One-Dimensional Arrays with References Created by Induction Variables

  • Zhang, Qing
    • Journal of Information Processing Systems
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    • v.10 no.4
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    • pp.523-542
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    • 2014
  • One-dimensional arrays with subscripts formed by induction variables in real programs appear quite frequently. For most famous data dependence testing methods, checking if integer-valued solutions exist for one-dimensional arrays with references created by induction variable is very difficult. The I test, which is a refined combination of the GCD and Banerjee tests, is an efficient and precise data dependence testing technique to compute if integer-valued solutions exist for one-dimensional arrays with constant bounds and single increments. In this paper, the non-continuous I test, which is an extension of the I test, is proposed to figure out whether there are integer-valued solutions for one-dimensional arrays with constant bounds and non-sing ularincrements or not. Experiments with the benchmarks that have been cited from Livermore and Vector Loop, reveal that there are definitive results for 67 pairs of one-dimensional arrays that were tested.

The Development of On-Line Model for the Prediction of Strain Distribution in Finishing Mill by FEM (유한요소법을 이용한 열간 사상 압연에서의 판 변형률 분포 예측 온라인 모델 개발)

  • 김성훈;이중형;황상무
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.05a
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    • pp.180-183
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    • 2003
  • In this research, on-line model for prediction of effective strain distribution hi strip on finishing mill process is prescribed. It has been developed using several selected non-dimensional parameters and previously made average effective strain model via series of finite element process simulations, $\Delta$$\varepsilon$ was introduced to describe the effective strain distribution in strip. To confirm adequate non-dimensional variables uniqueness test was done. And to decide the order of polynomial in on-line model equation tendency test for each variables was done. The prediction accuracy of the proposed model is examined through comparison with finite element calculation results.

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Errors in One-Dimensional Heat Transfer Analysis in a Hollow Cylinder Feedwater Pipe (속이 빈 원관에서 1차원적인 열전달 해석의 오차)

  • Gang, Hyeong-Seok
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.20 no.2
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    • pp.689-696
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    • 1996
  • A comparison is made of the heat loss from a hollow cylinder, computed using an one-dimensional analytic method and a two-dimensional separation of variables scheme. For a two-dimensional analysis, the temperature of the inner surface as a boundary condition can be varied along the length of the cylinder by varing the temperature variation factor, b. Comparisons of the heat loss from the hollow cylinder using these two methods are given as a function of non-dimensional cylinder length, the ratio of the outer radius to the inner radius, temperature variation factor and Biot number. The result shows that the value of the heat loss from the hollow cylinder obtained using the one-dimensional analytic method becomes close to the value given by the two-dimensional separation of variables scheme as the value of Biot number and the non-dimensional hollow cylinder length increase and as the ratio of the outer radius to the inner radius decreases.

Heat Transfer from each surface for a 3-D Thermally Asymmetric Rectangular Fin

  • Kang, Hyung Suk
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.4 no.2
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    • pp.153-163
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    • 2000
  • The non-dimensional convective heat losses from each surface are investigated as a function of the non-dimensional fin length, width and the ratio of upper surface Biot number to bottom surface Biot number (Bi2/Bi1) using the three-dimensional separation of variables method. Heat loss ratio in view of each surface with the variation of Bi2/Bi1 is presented. The variation of the non-dimensioal temperare profile along the fin center line for a thermally asymmetric conditions is also presented.

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FE-based Strip Mean Temperature Prediction On-Line Model in Hot Strip Finishing Mill by using Dimensional Analysis (차원해석을 통한 열간 사상압연중 온도해석모델 개발)

  • 이중형;곽우진;황상무
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.05a
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    • pp.176-179
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    • 2003
  • The mean temperature prediction of strip is very important in hot strip finishing mill because of affecting on product quality and shape. Also, temperature can be used by basic information in other on-line control models with affecting control accuracy in factory. So, FE based on-line temperature model was developed for predicting strip mean temperature accurately in various process conditions and factory environments. There are many variables in affecting strip mean temperature in on-line states of factory. But some problems are occurred in considering all variables for making temperature model because of the bad efficiency of regression or fitting analysis. In this report, we have adopted dimensional analysis for solving these problems. We have many variables with dimensions affecting strip temperature but we are able to make non-dimensional variables less than dimensional variables from the combination of dimensional variables caused by PI-Theorem in fluid mechanics. The developed models are divided by two parts. The one is interstand temperature prediction model. The other is roll gap temperature model.

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A Heat Transfer Analysis of a Thermally Asymmetric Triangular Fin; Based on Fin Tip Effect (열적 비대칭 삼각 핀의 열전달 해석; 핀 끝 효과에 기준)

  • Kang, Hyung-Suk
    • Journal of Industrial Technology
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    • v.22 no.B
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    • pp.21-26
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    • 2002
  • The non-dimensional heat loss from a thermally asymmetric triangular fin is investigated as a function of a ratio of upper and lower surface Biot numbers (Bi2/Bi1), the non-dimensional fin length and tip surface Biot number using the two-dimensional separation of variables method. The effect of fin tip surface Biot number on the variation of the non-dimensional temperature along the sloped upper and lower surfaces for the thermally asymmetric condition is presented. The relationship between the non-dimensional fin length and the fin tip surface Biot number for equal amount of heat loss is also discussed as well as the relationship between upper surface Biot number and tip surface Biot number for equal amount of heat loss.

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Optimization of a 3-D Thermally Asymmetric Rectangular Fin

  • Gang, Hyeong-Seok
    • Journal of Mechanical Science and Technology
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    • v.15 no.11
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    • pp.1541-1547
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    • 2001
  • The non-dimensional fin length for optimum heat loss from a thermally asymmetric rectangular fin is represented as a function of the ratio of the bottom surface Biot number to the top surface Biot number, fin tip surface Biot number and the non-dimensional fin width. Optimum heat loss is taken as 98% of the maximum heat loss. For this analysis, three dimensional separation of variables method is used. Also, the relation between the ratio of the bottom surface Biot number to the top surface Biot number and the ratio of the right surface Biot number to the left surface Biot number is presented.

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An Empirical Acoustic Impedance Model for the Design of Acoustic Resonator with Extended Neck at a High Pressure Environment (높은 음압에서의 내부 확장관형 음향 공명기의 설계를 위한 실험적 음향 임피던스 모델)

  • Park, Soon-Hong;Seo, Sang-Hyun
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.12
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    • pp.1199-1205
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    • 2012
  • An empirical acoustic impedance model of acoustic resonators with extended neck at a high sound pressure environment is proposed. The acoustic resonator with extended neck into its cavity is appropriate for the launcher fairing application because the length of neck does not increase the total height of the resonator. This enables one to design slim and light acoustic resonators for launch vehicles. The suggested acoustic impedance model considers the incident pressure and geometric variables(the neck length, the perforation ratio and the hole diameter) in terms of non-dimensional variables. Several acoustic resonators with extended neck are manufactured and their wall impedances are measured according to the pre-defined incident pressure levels. Effects of non-dimensional variables on the non-linear acoustic impedance are investigated so that a simple non-linear impedance model for the launcher fairing application can be proposed. It is demonstrated that the estimated acoustic resistance and acoustic length correction show reasonable agreement with the measured ones within the range of design parameters for launcher fairings.

Performance Analysis of a Thermally Asymmetric Triangular Fin (열적 비대칭 삼각 휜의 성능해석)

  • Gang, Hyeong-Seok
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.26 no.1
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    • pp.66-73
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    • 2002
  • Fin effectiveness and efficiency of a thermally asymmetric triangular fin are represented as a function of the ratio of fin lower surface Biot number to upper surface Biot number and the non-dimensional fin length. For this analysis, two dimensional separation of variables method is used. When fin effectiveness is 2 and efficiency is 90%, the relationship between the non-dimensional fin length and the ratio of fin lower stir(ace Biot number to upper surface Biot number is shown. The relationship between the non-dimensional fin length and the upper surface Biot number for the same condition is also presented.

Three-Dimensional Performance Analysis of a Thermally Asymmetric Rectangular Fin

  • Kang, Hyung-Suk
    • International Journal of Air-Conditioning and Refrigeration
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    • v.9 no.2
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    • pp.94-101
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    • 2001
  • Fin effectiveness and efficiency of a thermally asymmetric rectangular fin are represented as a function of non-dimensional fin length, width, fip tip surface Biot number and the ratio of fin bottom surface Biot number to top surface Biot number. For this analysis, three dimensional separation of variables method is used. One of the results shows that fin effectiveness can be increased or decreased depending on the fin length as the fin tip surface Biot number increases while fin efficiency decreases without depending on that as the fin tip surface Biot number increases.

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