• Title/Summary/Keyword: CFD

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A Study on the Resistance Performance and Flow Pattern of High Speed Planing Hull using CFD (전산유체계산을 통한 고속 활주선의 저항성능 및 유동분포 해석)

  • Park, Kyurin;Kim, Dong Jin;Kim, Sun Young;Rhee, Shin Hyung
    • Journal of the Society of Naval Architects of Korea
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    • v.56 no.1
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    • pp.23-33
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    • 2019

  • Unmanned Surface Vehicle (USV) is being developed to do maritime survey and maritime surveillance at Korea Research Institute of Ships & Ocean engineering (KRISO). The goal is that USV should be operated at the maximum speed of 45 knots and it should be operated at sea state 4. Therefore the planing hull of USV should be excellent in resistance performance and manoeuvring performance. It is needed to check its performance using Experimental Fluid Dynamics (EFD), Computational Fluid Dynamics (CFD) or analytic method before designing the hull. In this study, resistance performance was analyzed by EFD and CFD. EFD with heave and pitch was performed at high speed towing system in Seoul National University. CFD was performed using SNUFOAM based on openFOAM with dynamic mesh to calculate running attitudes. The results of CFD were compared with EFD results. The results of CFD were resistance, running attitudes and wave height. The flow distribution and pressure distribution were also analyzed. The results of numerical resistance was under estimated than EFD. Even though the results of CFD have a slight limitation, it can be successfully used to estimate the resistance performance of planing hull. In addition it can be used as a supplement for EFD results.

  • https://doi.org/10.3744/SNAK.2019.56.1.023 인용 PDF KSCI

CFD-based Path Planning and Flight Safety Assessment for Drone Operation in Urban Areas (CFD를 이용한 도심내 드론 비행 경로 계획 및 안전성 평가)

  • Geon-Hong Kim;Ayoung Hwang;Hyoyeong Kim;Yeonmyeong Kim
    • Journal of Aerospace System Engineering
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    • v.18 no.2
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    • pp.40-46
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    • 2024

  • This study suggests a method to enhance drone flight path planning and safety evaluation in urban areas using Computational Fluid Dynamics (CFD). As the use of drones in urban environments has been growing rapidly, there is a lack of established methods for path planning and safety evaluation, which leads to a risky approach relying on experimental methods. Therefore, this research takes into account the intricate 3D fluid dynamics between drones and buildings by employing CFD to quantitatively plan flight paths and evaluate their safety. To accomplish this, the study focuses on Gimcheon Innovation City as the target area and collects relevant terrain and building data, and selects prospective flight routes. CFD analysis is then carried out to gather essential data for flight simulations and safety assessment. The safety assessments are conducted based on environmental fluid dynamics when the drone operates along the proposed flight paths

  • https://doi.org/10.20910/JASE.2024.18.2.40 인용 PDF

Defect Detection and Cause Analysis for Copper Filter Dryer Quality Assurance (Copper Filter Dryer 품질보증을 위한 결함 검출 및 원인 분석)

  • SeokMin Oh;JinJe Park;Van-Quan Dao;ByungHo Jang;HeungJae Kim;ChangSoon Kim
    • Journal of Korea Society of Industrial Information Systems
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    • v.29 no.1
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    • pp.107-116
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    • 2024

  • Copper Filter Dryer (CFD) are responsible for removing impurities from the circulation of refrigerant in refrigeration and cooling systems to maintain clean refrigerant, and defects in CFD can lead to product defects such as leakage and reduced lifespan in refrigeration and cooling systems, making quality assurance essential. In the quality inspection stage, human inspection and defect judgment methods are traditionally used, but these methods are subjective and inaccurate. In this paper, YOLOv7 object detection algorithm was used to detect defects occurring during the CFD Shaft pipe and welding process to replace the existing quality inspection, and the detection performance of F1-Score 0.954 and 0.895 was confirmed. In addition, the cause of defects occurring during the welding process was analyzed by analyzing the sensor data corresponding to the Timestamp of the defect image. This paper proposes a method for manufacturing quality assurance and improvement by detecting defects that occur during CFD process and analyzing their causes.

  • https://doi.org/10.9723/jksiis.2024.29.1.107 인용 PDF

Development of an Aerodynamic Simulation for Studying Microclimate of Plant Canopy in Greenhouse - (2) Development of CFD Model to Study the Effect of Tomato Plants on Internal Climate of Greenhouse - (공기유동해석을 통한 온실내 식물군 미기상 분석기술 개발 - (2)온실내 대기환경에 미치는 작물의 영향 분석을 위한 CFD 모델개발 -)

  • Lee In-Bok;Yun Nam-Kyu;Boulard Thierry;Roy Jean Claude;Lee Sung-Hyoun;Kim Gyoeng-Won;Hong Se-Woon;Sung Si-Heung
    • Journal of Bio-Environment Control
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    • v.15 no.4
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    • pp.296-305
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    • 2006

  • The heterogeneity of crop transpiration is important to clearly understand the microclimate mechanisms and to efficiently handle the water resource in greenhouses. A computational fluid dynamic program (Fluent CFD version 6.2) was developed to study the internal climate and crop transpiration distributions of greenhouses. Additionally, the global solar radiation model and a crop heat exchange model were programmed together. Those models programmed using $C^{++}$ software were connected to the CFD main module using the user define function (UDF) technology. For the developed CFD validity, a field experiment was conducted at a $17{\times}6 m^2$ plastic-covered mechanically ventilated single-span greenhouse located at Pusan in Korea. The CFD internal distributions of air temperature, relative humidity, and air velocity at 1m height were validated against the experimental results. The CFD computed results were in close agreement with the measured distributions of the air temperature, relative humidity, and air velocity along the greenhouse. The averaged errors of their CFD computed results were 2.2%,2.1%, and 7.7%, respectively.

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