• 한국기계가공학회지
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• 제9권1호
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• pp.14-18
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• 2010

Car muffler has the role to form the exhaust gas from high temperature- pressure to lower level and reduce the generated noise. Because of this role, its durability decrease as deformation by heat is occurred. This study is to analyze the flow of exhaust gas inside muffler and its coupled thermal deformation with 3-D modeling and ANSYS. There is the fastest flow at the exit of muffler with the maximum velocity of 54 m/s. And the maximum deformation or equivalent stress is shown at this model respectively as 0.00435 mm or 3414.4 MPa by the influence of heat and pressure at part of intersection with inlet and body of muffler.

• International Journal of Reliability and Applications
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• 제2권1호
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• pp.73-80
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• 2001

A network, where links have different capacities, is considered to be in functioning state if a specified amount of flow can be transmitted through the network. In this paper, we consider the measures of importance of a link in such networks. We define the structural importance and reliability importance of a link when the required amount of flow is given. We also present the performability importance, which can be used to determine which links should be improved first in order to make the greatest improvement in the expected maximum flow of network. Numerical examples are presented as well for illustrative purpose.

• 대한산업공학회지
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• 제15권2호
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• pp.11-22
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• 1989

The problem of scheduling n-jobs on m-uniform parallel machines is considered, in which each job has a release time, a deadline, and a processing requirement. The job processing requirements are allocated to the machines so that the maximum of the load differences between time periods is minimized. Based on Federgruen's maximum flow network model to find a feasible schedule, a polynomially bounded algorithm is developed. An example to show the effectiveness of our algorithm is presented.

• 한국국방경영분석학회지
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• 제18권2호
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• pp.151-166
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• 1992

In this paper, we define a problem finding a simple path that maximizes the sum of the satisfied Origin-Destination (O-D) flows between nodes covered by that path as a Maximum O-D Flow Path Problem(MODEP). We established a formulation and suggested a method finding MODEP in a directed network. The method utilizes the constraint relaxation technique and the Dual All Integer Algorithm.

• 한국경영과학회지
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• 제32권2호
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• pp.89-97
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• 2007

We study the maximum integer multiflow problem and the minimum multicut problem in a ring network. Both problems in a general network are known to be NP-hard. In this paper, we develop polynomial time algorithms to solve the problems. We also prove that even In a ring network, maximum multiflow is not always integral, which implies that the amount of maximum integer flow does not always reach the minimum capacity of multicut.

• 대한기계학회논문집
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• 제14권3호
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• pp.694-701
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• 1990

본 연구에서는 열기관의 출력이, 주어진 열원사이에서 구성되는 사이클의 형 태에 의존한다는 점에서 최대출력 사이클이 어떤 형태가 될 것인가하는 문제에 촛점을 맞추어 사이클을 해석하고, 최대출력을 구하고자 한다.

• 대한기계학회논문집A
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• 제23권6호
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• pp.912-921
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• 1999

Shear stress acting on the arterial wall by blood flow is an important hemodynamic factor influencing blocking of blood vessel by thickening of an arterial wall. In order to study the effects of wall elasticity on the wall shear rate distribution in an artery-divergent graft anastomosis, a rigid and a elastic model are manufactured. These models are placed in a pulsatile flow loop, which can generate the desired flow waveform. Flow visualization method using a photochromic dye is used to measure the wall shear rate distribution. The accuracy of measuring technique is verified by comparing the measured wall shear rate in the straight portion of a model with the theoretical solution. Measured wall shear rates depend on the wall elasticity and flow waveform. The mean and maximum shear rate in the elastic model are lower than those in rigid model, and the decreases are more significant near the end of a divergent tube. The reduction of mean and maximum of wall shear rate in an elastic model are up to 17 percent.

• International Journal of Fluid Machinery and Systems
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• 제5권3호
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• pp.117-125
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• 2012

In the present experimental study, the authors try to clarify the characteristics of the flow around and inside a cross-flow impeller in a typical geometry, over a wide parameter range of an aspect ratio $L/D_2$. In order to eliminate the complicated casing factors, the impeller rotates in open space without any casings. As a result, by using hot wire anemometer measurements and by conventional flow visualisations with a particle image velocimetry technique, the authors show that both the outflow rate and the maximum vorticity attain the maximum for $L/D_2$ = 0.6. In order to investigate the aspect-ratio effect, we further reveal minute fluctuating pressures on an impeller end wall for a singular $L/D_2$ = 0.6. Especially in these pressure measurements, the eccentric vortex is prevented to revolute by the insertion of a tongue, in order to consider the spatial structure of flow more precisely.

• 한국해안해양공학회지
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• 제13권2호
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• pp.177-188
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• 2001

전난류에서 파와 해류가 합성하였을 때 발생하는 해저면 마찰력을 계산하는 방법을 고찰하였다. 전난류에서 일방향 흐름에 의한 마찰력의 산정방법으로 절점조정법을 제시하였으며, Bijker의 관측자료와 비교하여 절점조정치를 산정하였다. 파와 해류의 합성류에 의한 마찰력 계산방법으로 수정된 Bkjker 모형(BYO Model)과 수정된 Fredsoe 모형(FY Model)을 Bijker의 관측자료에 적용하였으며, BYO 모형에서 최대마찰력을 산정하는데 있어 새로운 개선책을 제시하였다.

• 한국물환경학회지
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• 제25권6호
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• pp.972-978
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• 2009

This study modifies the present total maximum daily load (TMDL) system of Ministry of Environment and applies to the Anyangcheon watershed. Hydrologic Simulation Program-FORTRAN (HSPF) model is used to simulate both runoff and non-point source pollution, simultaneously, instead of QUAL2E. The drought flow (355th daily flow) is proposed for the target water quantity since it is easier to satisfy low flow (275th daily flow) for the target water quality than drought flow. The increase of discharge is more than the increase of pollutant load except for the period under low flow. The measured unit loads for non-point source are used to consider the regional runoff characteristics. The measured water quantity and quality data are used since the ministry of environment supports only water quality. This analysis results show some reasons for the improvement of the present TMDL system of Korea.