• 제목/요약/키워드: non-dimensional parameters

검색결과 421건 처리시간 0.024초

모형 그물에 대한 어군행동의 수직 모델링에 관한 연구 - 해산어에 의한 수치 모델의 적합성 검토 - (A Study on the Numerical Modeling of the Fish Behavior to the Model Net - Fitness Examination of Numerical Model by the Marine Fish -)

  • 장호영;이주희
    • 수산해양기술연구
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    • 제34권2호
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    • pp.174-184
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    • 1998
  • In order to accumulate fundamental. data for control of fishes’ behavior at the real fishing ground, the fitness of the numerical model for describing the behavior of fishes was examined by the marine fish. Mullet, Mugil cephalus were used as experimental fishes. The numerical model of fishes’ behavior presented in our earlier paper was modified on the vertical movement of fish school. For the comparision of parameters of the modified numerical model between mullet and rainbow trout, the estimated values of parameters were identified with dimension. The fitness of the modified numerical model was examined by the comparision between experiment and simulation on the several indexes represented by fishes’ swimming characteristics. The obtained result are summarized a follows : 1. The non-dimensional parameter a’ of propulsive force and kb’ of interactive force by the experiment without model net showed a similarity, but the non-dimensional parameter k sub(c’) of schooling force for rainbow trout was lager than one for mullet and the non-dimensional parameter k sub(w’) of repulsive force for mullet was lager than one for rainbow trout. 2. The non-dimensional parameter a’ and k sub(b’) for rainbow trout by the experiment with model net were a little lager than ones for mullet, but non-dimensional parameter k sub(c’) and k sub(w’) for mullet were lager than ones for rainbow trout. 3. The non-dimensional parameter k sub(c’) and k sub(b’) showed the largest and the smallest value among the non-dimensional parameters for rainbow trout and mullet, respectively. 4. The fitness of the modified numerical model was confirmed by means of the compulsion between experiment and simulation on the swimming trajectory of fishes, the mean distance of individual from wall, the mean swimming speed, the mean swimming depth and the mean distance between the nearest individuals. Especially, the similarity of mean swimming depth was improved by using the modified numerical model.

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액적의 분사 거동을 지배하는 무차원수에 대한 수치해석적 연구 (NUMERICAL STUDY OF THE EFFECTS OF THE GOVERNING NON-DIMENSIONAL PARAMETERS ON THE DROPLET EJECTION BEHAVIOR)

  • 김은정;백제현
    • 한국전산유체공학회지
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    • 제17권2호
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    • pp.65-70
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    • 2012
  • The droplet ejection behavior from drop-on-demand printhead are investigated numerically in terms of the non-dimensional parameters. The numerical simulation is performed using a volume-of-fluid model. It is important to eject droplet within the printability range, where the droplet is ejected in stable manner without satellite droplets. Generally, the printability range has been determined by Z number, which is the inverse of Oh number. However, it is found that the ejection of droplets with same Z number can exhibit different behavior depending on the value of Ca and We number. Therefore, it is insufficient to determine the printability range only with Z number. Instead, other non-dimensional parameters, such as Ca and We number, should be considered comprehensively.

피스톤슬랩에 의한 엔진 진동현상의 분석과 예측 (Analysis and Prediction of Piston-Slap Induced Vibration)

  • 권기웅;김양한
    • 대한기계학회논문집
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    • 제17권12호
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    • pp.3045-3054
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    • 1993
  • The mechanics related with piston-slap induced vibration has been studied in terms of non-dimensionalized dynamic equation of motion, various non-dimensional parameters such as non-dimensional side-thrust force and non-dimensional impact velocity throughout the numerical simulation. Experimental verification on the suggested prediction method has been also performed by using single cylinder engine which was carefully designed and manufactured to wisely control the engine parameters, especially clearance and the mass of piston. The predicted and experimentally observed vibration signature confirm that the proposed method is practically useful.

U-FLATNESS AND NON-EXPANSIVE MAPPINGS IN BANACH SPACES

  • Gao, Ji;Saejung, Satit
    • 대한수학회지
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    • 제54권2호
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    • pp.493-506
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    • 2017
  • In this paper, we define the modulus of n-dimensional U-flatness as the determinant of an $(n+1){\times}(n+1)$ matrix. The properties of the modulus are investigated and the relationships between this modulus and other geometric parameters of Banach spaces are studied. Some results on fixed point theory for non-expansive mappings and normal structure in Banach spaces are obtained.

An Interference Avoidance Method Using Two Dimensional Genetic Algorithm for Multicarrier Communication Systems

  • Huynh, Chuyen Khoa;Lee, Won Cheol
    • Journal of Communications and Networks
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    • 제15권5호
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    • pp.486-495
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    • 2013
  • In this article, we suggest a two-dimensional genetic algorithm (GA) method that applies a cognitive radio (CR) decision engine which determines the optimal transmission parameters for multicarrier communication systems. Because a CR is capable of sensing the previous environmental communication information, CR decision engine plays the role of optimizing the individual transmission parameters. In order to obtain the allowable transmission power of multicarrier based CR system demands interference analysis a priori, for the sake of efficient optimization, a two-dimensionalGA structure is proposed in this paper which enhances the computational complexity. Combined with the fitness objective evaluation standard, we focus on two multi-objective optimization methods: The conventional GA applied with the multi-objective fitness approach and the non-dominated sorting GA with Pareto-optimal sorting fronts. After comparing the convergence performance of these algorithms, the transmission power of each subcarrier is proposed as non-interference emission with its optimal values in multicarrier based CR system.

Evaluation of the Tribological Parameters of Three-dimensional Surface Topography with Various Property

  • Uchidate, M.;Shimizu, T.;Iwabuchi, A.
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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    • pp.249-250
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    • 2002
  • In this paper, the relationship among the 3-D surface topography parameters are studied. Several surface topography parameters that are important in tribology are calculated against various surface topography data. 3-D surface data with desired properties are generated by using the non-causal 2-D auto-regressive (AR) model. The non-causal 2-D AR model is a random 3-D surface topography model that can generate 3-D surface topography data with specified parameters.

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이송되는 컵 내부의 자유 표면의 거동 특성에 대한 수치해석 (A Numerical Analysis of the Behavior of the Free Surface in a Moving Cup)

  • 홍태협;채희문;김창녕
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2007년도 춘계학술대회B
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    • pp.2997-3002
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    • 2007
  • A manipulator is operated for the motion of mechanical hands or arms by mechanical mechanism. When a cup including liquid inside is shifted by a manipulator, it is important to know how a free surface of the liquid moves. In this study, non-dimensional parameters have been found that affect the rise of the free surface in a cup moving with constant acceleration. The non-dimensional parameters are the dimensionless time, the ratio of inertia effect to vicous effect (Reynolds number), aspect ratio of the liquid inside the cup and acceleration ratio (Froude number). Through this study, the height of the free surface rise in a cup has been predicted. Generally the maximum rise of the free surface is dependent on the Reynolds number and Froude number strongly, but on the aspect ratio weakly. But the influence of the aspect ratio on the maximum rise of the free surface in not negligible in the range 10 < Re < 100.

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Limit analysis of 3D rock slope stability with non-linear failure criterion

  • Gao, Yufeng;Wu, Di;Zhang, Fei;Lei, G.H.;Qin, Hongyu;Qiu, Yue
    • Geomechanics and Engineering
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    • 제10권1호
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    • pp.59-76
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    • 2016
  • The non-linear Hoek-Brown failure criterion has been widely accepted and applied to evaluate the stability of rock slopes under plane-strain conditions. This paper presents a kinematic approach of limit analysis to assessing the static and seismic stability of three-dimensional (3D) rock slopes using the generalized Hoek-Brown failure criterion. A tangential technique is employed to obtain the equivalent Mohr-Coulomb strength parameters of rock material from the generalized Hoek-Brown criterion. The least upper bounds to the stability number are obtained in an optimization procedure and presented in the form of graphs and tables for a wide range of parameters. The calculated results demonstrate the influences of 3D geometrical constraint, non-linear strength parameters and seismic acceleration on the stability number and equivalent strength parameters. The presented upper-bound solutions can be used for preliminary assessment on the 3D rock slope stability in design and assessing other solutions from the developing methods in the stability analysis of 3D rock slopes.

Weighted sum Pareto optimization of a three dimensional passenger vehicle suspension model using NSGA-II for ride comfort and ride safety

  • Bagheri, Mohammad Reza;Mosayebi, Masoud;Mahdian, Asghar;Keshavarzi, Ahmad
    • Smart Structures and Systems
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    • 제22권4호
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    • pp.469-479
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    • 2018
  • The present research study utilizes a multi-objective optimization method for Pareto optimization of an eight-degree of freedom full vehicle vibration model, adopting a non-dominated sorting genetic algorithm II (NSGA-II). In this research, a full set of ride comfort as well as ride safety parameters are considered as objective functions. These objective functions are divided in to two groups (ride comfort group and ride safety group) where the ones in one group are in conflict with those in the other. Also, in this research, a special optimizing technique and combinational method consisting of weighted sum method and Pareto optimization are applied to transform Pareto double-objective optimization to Pareto full-objective optimization which can simultaneously minimize all objectives. Using this technique, the full set of ride parameters of three dimensional vehicle model are minimizing simultaneously. In derived Pareto front, unique trade-off design points can selected which are non-dominated solutions of optimizing the weighted sum comfort parameters versus weighted sum safety parameters. The comparison of the obtained results with those reported in the literature, demonstrates the distinction and comprehensiveness of the results arrived in the present study.

소형 원심형 팬의 형상변수가 성능에 미치는 영향에 대한 실험적 연구 (Experimental Study for the Effect of Dimensional Parameters on the Performance of Small Centrifugal Fans)

  • 최종수;이욱
    • 유체기계공업학회:학술대회논문집
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    • 유체기계공업학회 1998년도 유체기계 연구개발 발표회 논문집
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    • pp.57-63
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    • 1998
  • The performance of a centrifugal fan depends on the dimensional parameters of impeller, such as the inlet and exit diameter, area ratio, relative flow angles to the blade, and number of blades. These design parameters, however, are inter-related, so it is very difficult to identify the effect of each parameter to the fan performance. In this experimental study the effect of the design parameters on the performance of a small centrifugal impeller being used for vacuum cleaners are investigated. Total 30 shrouded impellers with 120mm diameter were tested and the results were non-dimensionalized to compare their performance.

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