• 제목/요약/키워드: Sliding Mesh

검색결과 78건 처리시간 0.04초

토마토 온실에서 방충망 설치에 의한 담배가루이 피해 경감 (Establishment of 60 Mesh Nets to Reduce Crop Loss by Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) in Tomato Greenhouse)

  • 정부근;이흥수;김영봉
    • 한국응용곤충학회지
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    • 제52권1호
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    • pp.23-27
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    • 2013
  • 담배가루이가 매개하는 토마토황화잎말림병(TYLCV) 예방을 목적으로 해충의 유입을 원천적으로 차단할 수 있는 방충망 설치에 대한 연구가 수행되었다. 담배가루이가 60메쉬망을 통과는 할 수 있지만, 83메쉬 이상의 방충망으로 완전히 차단할 수 있었다. 담배가루이의 온실 내 유입을 차단하기 위한 3연동 온실($21.0{\times}18.3m$)에 60메쉬 망실, $5.65(W){\times}2.05(H){\times}18.45(L)(m)$을 별도로 설치하였다. 60메쉬 망실 내에서 담배가루이 산란과 아메리카잎굴파리 가해흔적이 출입문 쪽에 국부적으로 몇몇 발견되었으나, 토마토황화잎말림병에 걸린 토마토는 없었다. 토마토의 초장, 엽장, 엽폭, 화방수, 당도 조사결과 망실유무에 따른 처리구간의 차이는 없는 것으로 나타났고, 수량에서도 유의성 있는 차이를 발견할 수 없었다. 실용적인 관점에서 방충망의 설치는 유리온실이나 장기간 사용가능한 비닐온실 등의 측창과 천창 및 출입구에 설치할 경우 유망할 것으로 생각되었다.

1600kW급 프로펠러 블레이드 공력설계 및 해석 (Aerodynamic Design and Analysis on 1600kW Class Propeller Blade)

  • 최원;김광해;원영수;이원중
    • 한국유체기계학회 논문집
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    • 제15권3호
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    • pp.19-24
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    • 2012
  • Propeller shall have high efficiency and improved aerodynamic characteristics to get the thrust to fly at high speed for the turboprop aircraft. That is way Clark-Y airfoil which is used to conventional 1600kW class aircraft propeller is selected as a blade airfoil. Adkins method is used for aerodynamic design and performance analysis with respect to the propeller design point. Adkins method is based on the vortex-blade element theory which design the propeller to satisfy the condition for minimum energy loss. propeller geometry is generated by varying chord length and pitch angle at design point of turboprop aircraft. The propeller design results indicate that is evaluated to be properly constructed, through analysis of propeller aerodynamic characteristics using the Meshless method and MRF, SM method.

CFD를 이용한 KRISO 추진효율 향상 장치(K-duct)의 성능 해석 (CFD Analysis of Performance of KRISO Devices (K-DUCT) for Propulsion Efficiency Improvement)

  • 서성부
    • 한국해양공학회지
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    • 제31권3호
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    • pp.183-188
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    • 2017
  • This paper provides numerical results for the estimation of the efficiency of KRISO energy saving devices in the design stage. A finite volume method is used to solve Reynolds averaged Navier-Stokes (RANS) equations, where the SST k-$\omega$ model is selected for turbulence closure. The propeller rotating motion is determined using a rigid body motion (RBM) scheme, which is called a sliding mesh technique. The numerical analysis focuses on predicting the power reduction by the designed KRISO devices (K-DUCT) under a self-propulsion condition. The present numerical results show good agreement with the available experimental data. Finally, it is concluded that CFD can be a useful method, along with model tests, for assessing the performance of energy saving devices for propulsion efficiency improvement.

대규모와 모사에 의한 3차원 소형축류홴의 운전부하에 따른 난류유동장 구조에 대한 연구 (A Study on the Structure of Turbulent Flow Fields According to the Operating Loads of Three-Dimensional Small-Size Axial Fan by Large Eddy Simulation)

  • 김장권;오석형
    • 동력기계공학회지
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    • 제19권5호
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    • pp.80-85
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    • 2015
  • The unsteady-state, incompressible and three-dimensional large eddy simulation(LES) was carried out to analyze the structure of turbulent flow fields according to the operating loads of three-dimensional small-size axial fan(SSAF). LES shows the best prediction performance in comparison with any other Reynolds averaged Navier-Stokes(RANS) method because static pressure coefficients analysed by LES show a little bit larger than measurements including all flow coefficients. Also, it can be known that the wake of SSAF is divided into from axial flow to radial flow before and behind stall region according to the increase of static pressure through LES analysis.

프로펠러와 고양력 장치와의 공력간섭에 대한 수치해석 연구 (NUMERICAL STUDY OF PROPELLER AND HIGH LIFT DEVICE AERODYNAMIC INTERFERENCES)

  • 박영민;김철완;정진덕;이해창
    • 한국전산유체공학회지
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    • 제16권4호
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    • pp.47-54
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    • 2011
  • A rotating propeller of turboprop aircraft gives much effect on the aerodynamic characteristics of wing such as lift, moment and stall. Specially propeller effect on the wing surface is much more dominant when aircrafts are in landing or take-off conditions. In the present paper, three dimensional Navier-Stokes simulations for the interaction of propeller and wing were carried out for medium sized turboprop aircraft. For rotating propeller, unsteady sliding mesh method was used to simulate a relative motion between moving and static bodies. For the power effect analysis in landing and take off configurations, double slotted flap was also considered and the aerodynamic characteristics were investigated. It was shown that the propeller slipstream enhanced the lift slope including maximum lift by eliminating local flow separation region and this enhancement was more dominant with high lift device.

비정렬 격자기법을 이용한 횡류팬(Cross-Flow Fan)의 비정상 유동해석 (NUMERICAL PREDICTION OF THE CROSS-FLOW FAN PERFORMANCE AND NOISE CHARACTERISTICS BY UNSTRUCTURED FLOW SOLVER ALGORITHM)

  • 조용;문영준
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 1998년도 추계 학술대회논문집
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    • pp.36-41
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    • 1998
  • The cross-flow fan performance and its sound noise characteristics are predicted by computational methods. The unsteady incompressible Navier-Stokes equations in moving coordinates are solved by a SMAC method on unstructured triangular meshes, using a sliding mesh technique at the interface between the domain rotating with blades and the rest stationary part. The computationally predicted fan performance was favorably compared with experiment, and some numerical aspects of simulating the cross-flow fan are discussed. With the computed unsteady flow field, aeroacoustic sound noise of the fan is predicted by the Lighthill-Curie equation. The unsteady surface pressure fluctuations on stabilizer enables a prediction of BPF noise of the uniform pitch blade fan quite accurately. The aeroacoustic sound noise characteristics of both uniform and random pitch blade fans are also examined by SPL spectrum analysis.

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1단 터빈에서 축간격 변화가 비정상 이차유동 및 성능에 미치는 영향 (The effects of axial spacing on the unsteady secondary and performance in one-stage axial turbine)

  • 박준영;백제현
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2002년도 학술대회지
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    • pp.537-540
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    • 2002
  • Flow through turbomachinery has a very complex structure and is intrinsically unsteady. Especially, recent design trend to turbomachinery with short axial spacing makes the flow extremely complex due to the interaction between stator and rotor. Therefore, it is very necessary to clearly understand the complex flow structure to obtain the high efficiency turbomachinery. So, in this paper, the effects of axial spacing on the unsteady secondary flow performance in the one stage turbine are investigated by three-dimensional unsteady flow analysis. The three-dimensional solver is parallelized using domain decomposition and Message Passing Interface(MPI) standard to overcome the limitation of memory and the CPU time in three-dimensional unsteady calculation. A sliding mesh interface approach has been implemented to exchange flow information between blade rows.

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상용 CFD코드를 이용한 횡류홴 공력소음 특성 해석 (Analysis of the aeroacoustic characteristics of cross-flow fan using commercial CFD code)

  • Jeon, Wan-Ho;Gi, Jeong-Mun
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2002년도 추계학술대회논문초록집
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    • pp.334.1-334
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    • 2002
  • In this study, a cross-flow fan system used in indoor unit of the split-type air conditioner is analyzed by computational simulation. A commercial CFD code - Fluent - is used to calculate the performance and its unsteady flow characteristics. The unsteady incompressible Wavier-Stokes equations are solved using a sliding mesh technique on the interface between rotating fan region and the outside. The acoustic pressure is calculated by using Ffowcs-Williams and Hawkings equation. (omitted)

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비정렬 격자를 이용한 선체 주위의 유동 해석 (ANALYSIS OF FLOW AROUND SHIP USING UNSTRUCTURED GRID)

  • 전제형;이상의;권재웅;손재우
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 2011년 춘계학술대회논문집
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    • pp.187-193
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    • 2011
  • In this report, We compared the actual test with the result of pow calculation and Resistance/Self-propulsion of the ship using STAR-CCM+ which is the commercial Reynolds Averaged Navier-Strokes(RANs) Solver. The calculation model was the KRISO Container Ship and 205K Bulk Carrier of Sungdong shipbuilding company. For this calculation, We used Realizable K-Epsilon model for flaw analysis, VOF method for the free surface creation, Moving Reference Frame method for reducing the POW calculation time, and Sliding Mesh method for Self-Propulsion analysis. Calculation of Resistance and Self-Propulsion includes the free-surface. And all calculations in this report were based on unstructured grids.

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프로펠러 후류 효과로 인한 날개의 공력 특성 수치해석 (Numerical Simulation of Propeller Slipstream Effect on Wing Aerodynamic Characteristics)

  • 박영민;김철완;정진덕;이해창
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 2011년 춘계학술대회논문집
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    • pp.202-205
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    • 2011
  • A rotating propeller of turboprop aircraft gives much effect on the aerodynamic characteristics of wing such as lift, moment and stall. Specially, a rotating propeller changes the lift and moment characteristics when aircrafts are in landing or take-off condition. In the present paper, 3-dimensional Navier-Stokes simulations for the interaction of propeller and wing were carried out. For rotating propeller, unsteady sliding mesh method was used to simulate a relative motion. For the power effect analysis in landing and take off configurations, double slotted flap was also considered and the aerodynamic characteristics were investigated. It was shown that the propeller slipstream enhanced the lift slope including maximum lift and this enhancement was more dominant with high lift device.

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