• Title, Summary, Keyword: 오픈폼

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Large Eddy Simulation of Free Motion of Marine Riser using OpenFOAM (오픈폼을 활용한 자유진동하는 라이저 주위 유동의 LES 해석)

  • Jung, Jae-Hwan;Jeong, Kwang-Leol;Gill, Jae-Heung;Jung, Dongho
    • Journal of Ocean Engineering and Technology
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    • v.33 no.5
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    • pp.387-393
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    • 2019
  • In this study, the free motion of a riser due to vortex shedding was numerically simulated with Large Eddy Simulation (LES) and Detached Eddy Simulation (DES) turbulence models. A numerical simulation program was developed by applying the Rhie-Chow interpolation method to the pressure correction of the OpenFOAM standard solver pimpleDyMFoam. To verify the developed program, the vortex shedding around the fixed riser at Re = 3900 was calculated, and the results were compared with the existing experimental and numerical data. Moreover, the vortex-induced vibration of a riser supported by a linear spring was numerically simulated while varying the spring constant. The results are compared with published direct numerical simulation (DNS) results. The present calculation results show that the numerical method is appropriate for simulating the vortex-induced motion of a riser, including lock-in phenomena.

Investigation of Applicability of OpenFOAM for Regular Wave Modeling of Floating Vertical Plate (부유식 연직판의 규칙파 모델링을 위한 오픈폼 적용성 검토)

  • Oh, Sang-Ho;Kim, Gunwoo
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.29 no.6
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    • pp.382-388
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    • 2017
  • This study performed an OpenFOAM-based numerical modeling for simulating performance of wave reduction by a floating vertical plate. Based on the Waves2FOAM library, an internal wave generation and energy dissipation with sponge layers schemes were further implemented. The performance of wave generation and dissipation was first tested with a simple two-dimensional analysis. Then, numerical simulation was carried out with the experimental data of Briggs et al. (2001) for the two regular wave cases. In general, the modeling results agreed well with the experimental data, showing better agreement than the numerical analysis by WAMIT that is included in Briggs et al. (2001).

Development of Mobile Open API Platform Using XForms Enabled Browser (XForms지원 브라우저를 이용한 모바일 오픈 API 플랫폼 개발)

  • Yoo, Ga-Yeon;Lee, Eun-Jung
    • Proceedings of the Korea Information Processing Society Conference
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    • pp.444-447
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    • 2007
  • 인터넷 환경의 변화와 함께 많은 서비스가 오픈 API 형태로 지원되면서 이들을 결합하고 이용하는 웹 기반의 클라이언트 프로그램이 모바일 환경의 주요한 어플리케이션 형태로 등장했다. 또한 차세대 웹 폼 언어인 XForms는 간편하고 효과적인 UI기술 언어로서 알려져 있으며, 다양한 모달리티를 지원할 수 있고 장치 독립성을 제공할 수 있어 모바일 장치에 더 적합하다. 본 논문에서는 오픈 API를 지원하는 XFroms 페이지를 설계하고, XForms의 특징을 살려 성능 및 표현력을 개선한 브라우저를 구현하였다. 또한 오픈 API를 사용하는 모바일 블로그 서비스를 XForms기반 오픈 API 페이지들을 통해 작성함으로써 제안된 시스템의 표현력과 유연성을 증명하였다.

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Numerical Analysis of Four Circular Columns in Square Array and Wave Interaction (파랑과 정사각형 배열의 원형 기둥 구조물의 상호작용 수치해석)

  • Song, Seongjin;Park, Sunho
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.23 no.5
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    • pp.558-565
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    • 2017
  • Accurate prediction of wave-structure interactions is important in the safety and design cost effectiveness of fixed and floating offshore structures exposed to extreme environmental conditions. In this study, regular waves and circular column structure interactions for four circular columns in regular waves are analyzed. To simulate 3D two-phase flow, open source computational fluid dynamics libraries, called OpenFOAM, were used. When the four circular columns are arranged in a square array, the interactions according to the incident slopes of the regular waves are analyzed. The wave run-up in the circular column surface was compared according to the slope of the incident wave. It was confirmed that high amplitude waves are generated between the circular columns due to the interaction between the circular column and the incident wave. It is expected that this analytical result will be used as the basic data of the study on the air gap due to the interaction between the structure and incident wave.

Validation and Application of OpenFOAM for Prediction of Livestock Airborne Virus Spread (공기 중 축산질병 확산예측을 위한 오픈폼 도입 및 검증)

  • Roh, Hyun-Seok;Seo, Il-Hwan;Lee, In-Bok
    • Journal of The Korean Society of Agricultural Engineers
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    • v.56 no.1
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    • pp.81-88
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    • 2014
  • Accurate wind data is essential for predicting airborne spread of virus. OpenFOAM was used for computational fluid dynamics (CFD) simulation procedure which is under GNU GPL (General Public License). Using complex terrain, DEM (Digital Elevation Map) that was prepared from GIS information covering a research site is converted to a three dimensional surface mesh that is composed by quad and full hexahedral space meshes. Around this surface mesh, an extended computational domain volume was designed. Atmospheric flow boundary conditions were used at inlet and roughness height and was considered at terrain by using rough wall function. Two different wind conditions that was relatively stable during certain periods were compared in 3 different locations for validating the accuracy of the CFD computed solution. The result shows about 10 % of difference between the calculated result and measured data. This procedure can simulate a prediction of time-series data for airborne virus spread that can be used to make a web-based forecasting system of airborne virus spread.

INTRODUCTION TO OPENFOAM: OPEN SOURCE SOFTWARE (Source 공개 코드 OpenFOAM 소개)

  • Park, J.K.;Kang, K.H.
    • 한국전산유체공학회:학술대회논문집
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    • pp.431-436
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    • 2010
  • Recently, several open source codes for computational fluid dynamics (CFD) have been emerged and are spreading fast. Our group has chosen OpenFOAM as a platform to develop our own in-house code. In this paper, we would like to share the information on the codes and what we have experienced so far. We introduce several features of OpenFOAM, which include the performance compared with commercial packages, estimation for current user population and our own prospect for future improvement in performance and growth in user population. In addition, we briefly introduce our experience gained in embedding the level set method into the OpenFOAM.

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REVIEW ON OPENFOAM - AN OPEN SOURCE SOFTWARE (Source 공개 코드 OpenFOAM에 대한 리뷰)

  • Park, J.K.;Kang, K.H.
    • Journal of computational fluids engineering
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    • v.15 no.3
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    • pp.46-53
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    • 2010
  • Recently, several open source codes for computational fluid dynamics (CFD) have been introduced and are spreading fast. Our group has chosen the OpenFOAM as a platform to develop our own in-house code. In this brief review, we would like to share the information on the codes and what we have experienced so far. We introduce several features of OpenFOAM, which include the performance compared with commercial packages, estimation for current user population, and our own prospect for future improvement in performance and growth in user population. In addition, we briefly introduce our experience gained in embedding the level set method into the OpenFOAM.

NUMERICAL INVESTIGATION OF SHOCK-BUFFET ON TRANSPORT AIRCRAFT WITH CHANGING THE POSITION OF NACELLE/PYLON (항공기 Nacelle/pylon 위치에 따른 Shock-Buffet 현상의 수치적 연구)

  • Kim, S.H.;Yee, K.J.;Oh, S.J.
    • Journal of computational fluids engineering
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    • v.19 no.3
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    • pp.69-76
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    • 2014
  • The shock buffet on a transonic transport aircraft are negative factors that reduce the aerodynamic performance of aircraft. The parametric studies were performed for position of nacelle/pylon to estimate the trend of flow mechanism under the wing that affects shock buffet. To generate external mesh of aircraft configuration that change the position of nacelle, snappyHexMesh provided in OpenFOAM was applied. Implicit density-based solver(ISAAC) was used for flow analysis. The change of nacelle position along horizontal direction dynamically affected the aerodynamic performance of transonic transport aircraft as comparing that of vertical direction. As a result of the parametric study of nacelle/pylon position, it was confirmed that the optimal position of nacelle can be obtained by aerodynamic design.

A Study on CFD Uncertainty Analysis and its Application to Ship Resistance Performance Using Open Source Libraries (CFD의 불확실성 해석에 대한 고찰 및 소스 공개 코드를 이용한 선박저항성능에의 적용)

  • Seo, Seonguk;Song, Seongjin;Park, Sunho
    • Journal of the Society of Naval Architects of Korea
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    • v.53 no.4
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    • pp.329-335
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    • 2016
  • In the present paper, Computational fluid dynamics (CFD) uncertainty analysis proposed by ITTC was investigated and applied to ship resistance performance using open source libraries, called OpenFOAM. Uncertainties for grid size, time step and iteration number were studied. Wave patterns and hull wave profile were compared for various uncertainty parameters. From results, grid size uncertainty was mainly contributed to simulation numerical uncertainty.

Direct Numerical Simulations of Turbulent Boundary Layer using OpenFOAM and Adapted Mesh (OpenFOAM과 어댑티드 격자를 이용한 난류 경계층의 직접 수치 모사)

  • Lee, Sang Bong
    • Journal of the Society of Naval Architects of Korea
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    • v.53 no.3
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    • pp.210-216
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    • 2016
  • Direct numerical simulations of a spatially developing turbulent boundary layer on a flat plate have been performed to verify the applicability of OpenFOAM and adapted mesh with prism layers to turbulent numerical simulation with high fidelity as well as provide a guideline on numerical schemes and parameters of OpenFOAM. Reynolds number based on a momentum thickness at inlet and a free-stream velocity was Reθ=300. Time dependent inflow fields with near-wall turbulent structures were generated by a method of Lund et al. (1998), which was to extract instantaneous velocity fields from an auxiliary simulation with rescaled and recycled velocities at inlet. To ascertain the statistical characteristics of turbulent boundary layer, the mean profiles of streamwise velocity and turbulent intensities obtained from structured and adapted meshes were compared with the previous data.