• Title/Summary/Keyword: airfoil

Search Result 732, Processing Time 0.026 seconds

Flow Control on Wind Turbine Airfoil with a Vortex Cell (와류 셀을 이용한 풍력블레이드 에어포일 주위 유동 제어)

  • Kang, Seung-Hee;Kim, Hye-Ung;Ryu, Ki-Wahn;Lee, Jun-Shin
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.40 no.5
    • /
    • pp.405-412
    • /
    • 2012
  • A flow control on airfoil installed a vortex cell for high efficiency wind turbine blade in stationary and dynamic stall conditions have been numerically investigated by solving the compressible Navier-Stokes equations. The numerical scheme is based on a node-based finite-volume method with Roe's flux-difference splitting and an implicit time-integration method coupled with dual time step sub-iteration. The computed result for the airfoil in the stationary showed that lift-drag ratio increases due to low pressure by the vortex cell. The oscillating airfoil with the vortex cell showed that the magnitude of hysteresis loop is reduced due to the enhanced vortex in the cell.

Aerodynamic Analysis Automation and Analysis Code Verification of an Airfoil in the Transonic Region (천음속영역에서 에어포일의 공력해석 자동화 및 해석코드 검증)

  • Kim, Hyun;Chung, Hyoung-Seog;Chang, Jo-Won;Choi, Joo-Ho
    • Journal of the Korean Society for Aviation and Aeronautics
    • /
    • v.14 no.3
    • /
    • pp.7-15
    • /
    • 2006
  • Aerodynamic analysis of an airfoil in the transonic region was automated in order to enable parametric study by using the journal file of the commercial analysis code FLUENT, pre/post process Gambit and computational mathematics code MATLAB. The automated capability was illustrated via NACA 0012 and RAE 2822 airfoils. This analysis was carried out at Mach numbers ranged from 0.70 to 0.80, angles of attack; 1$^{\circ}$, 2$^{\circ}$ and 4$^{\circ}$, Reynolds numbers; 4.0${\times}$106, 6.5${\times}$106. The analysis results of a pressure coefficient were verified by comparing with the experimental data which were measured in terms of chord length because the pressure coefficient of an airfoil surface is a good estimator of flow characteristics. The results of two airfoils show that this analysis code is useful enough to be used in the design optimization of airfoil.

  • PDF

Utilizing EDISON_CFD for Airfoil selection of Human Powered Aircraft (인력비행기 Airfoil 선정을 위한 EDISON_CFD 활용)

  • Kim, Gyeong-Nam;Ryu, Gi-Myeong;Song, Yun-Jeong
    • Proceeding of EDISON Challenge
    • /
    • 2012.04a
    • /
    • pp.101-104
    • /
    • 2012
  • 본 논문에서는 충남대학교에서 설계하고 있는 인력비행기인 Volante의 주익 에어포일을 선정하기 위하여 교육 및 연구를 위한 CFD 해석 프로그램인 EDISON_CFD를 이용하여 후보군으로 있는 에어포일들의 경향성을 확인하고 성능이 좋은 에어포일을 선정하였다. 또한 CFD 프로그램으로 상용화된 Fluent와 비교하여 EDISON_CFD의 신뢰성을 확인하였다.

  • PDF

AERODYNAMIC DESIGN OPTIMIZATION OF ROTOR AIRFOIL WITH MULTIPLE CONSTRAINTS (다중제약조건을 갖는 로터익형의 공력 최적 설계)

  • Lee, S.M.;Sa, J.H.;Jeon, S.E.;Kim, C.J.;Park, S.H.;Chung, K.H.
    • Journal of computational fluids engineering
    • /
    • v.15 no.2
    • /
    • pp.79-85
    • /
    • 2010
  • Aerodynamic design optimization of rotor airfoil has been performed with advanced design method for improved aerodynamic characteristics of ONERA airfoils. A multiple response surface method is used to consider various requirements in rotor airfoil design. Shape functions for mean camber line are proposed to extend possible design domain. Numerical simulations are performed using KFLOW, a Navier-Stokes solver with shear stress transport turbulence model. The present design method provides favorable configurations for the high performance rotor airfoil. Resulting optimized airfoils give better aerodynamic performance than the baseline airfoils.

AERODYNAMIC DESIGN OPTIMIZATION OF OA AIRFOIL USING THE RESPONSE SURFACE METHOD (반응면 기법을 사용한 OA 익형의 공력 최적 설계)

  • Sa, J.H.;Park, S.H.;Kim, C.J.;Yun, C.Y.;Kim, S.H.;Kim, S.H.;Lee, J.W.
    • 한국전산유체공학회:학술대회논문집
    • /
    • 2009.04a
    • /
    • pp.51-56
    • /
    • 2009
  • Optimization with metamodel is one of numerical optimization methods. Response surface method is performed for making metamodel. The Hcks-Henne function is used for designing 2D shape of the airfoil and spring analogy is used to change the grid according to the change in shape of the airfoil. Aerodynamic coefficient required for response surface method are obtained by using Navier-Stokes solver with $\kappa-\omega$ shear stress transport turbulence model. For the baseline airfoils, OA 312, OA 309, and OA 407 airfoils select and optimize to improve aerodynamic performance.

  • PDF

Effects of the Impeller Inlet Tip Clearance on the Flow and Performance of Airfoil Fans (임펠러 흡입구 간극이 원심형 에어포일 송풍기의 성능에 미치는 영향)

  • Kang, Shin-Hyoung;Kim, Young-Jae
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.23 no.8
    • /
    • pp.957-968
    • /
    • 1999
  • Performance tests of an airfoil fan and measurement of flow fields at the impeller exit are carried out to investigate the effects of the tip clearance between the rotor and inlet casing on the impeller performance. The impeller is twelve bladed of NACA 65-810 airfoils and tested with 3 different size of gap; 1, 2, 4mm. The relative decrease of pressure rising performance of the fan is 15 percent for the design flow rate when the gap size is 1 percent of the impeller diameter. The reduction of performance becomes large as the flow rate increases. The leakage flow through the clearance affects the through flow of the impeller, which results in decrease of the slip factor as well as the impeller efficiency. The data base obtained in the present study can be used for the design and flow analysis of the airfoil fans.

Development of a Lift Correction Method for Shear Flow Effects in BEM Theory (BEM 이론을 위한 전단유동 효과 보정 기법 개발)

  • Lee, Kyung Seh;Jung, Chin Hwa;Park, Hyun Chul
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 2011.05a
    • /
    • pp.57.2-57.2
    • /
    • 2011
  • In this study, the effects of shear flows around a 2-dimensional airfoil, S809 on its aerodynamic characteristics were analyzed by CFD simulations. Various parameters including reference inflow velocity, shear rate, angle of attack, and cord length of the airfoil were examined. From the simulation results, several important characteristics were found. Shear rate in a flow makes some changes in the lift coefficient depending on its sign and magnitude but angle of attack does not have a distinguishable influence. Cord length and reference inflow also cause proportional and inversely proportional changes in lift coefficient, respectively. We adopted an analytic expression for the lift coefficient from the thin airfoil theory and proposed a modified form applicable to the traditional load analysis procedure based on the blade element momentum theory. Some preliminary results applied to an well known load simulation software, FAST, are presented.

  • PDF

A Numerical Study on the Flowfield around a NACA 0021 Airfoil at Angles of Attack (NACA 0021 익형 유동장의 수치해석적 연구)

  • Kim, Sang-Dug
    • Journal of the Korean Society for Aviation and Aeronautics
    • /
    • v.24 no.4
    • /
    • pp.20-25
    • /
    • 2016
  • A primary benefit of flight at high angle-of-attack conditions is to be able to reduce the speed of flight and maneuvers, which can enhance the capability of sensing and obstacle avoidance for a small UAV. The flight at high angle-of-attack conditions, however, is easy to be beyond stall which is characterized by substantial flow separation over an airfoil. Current numerical analysis was conducted on the capabilities of three representative turbulence models to predict the aerodynamic characteristics of a typical airfoil at angle-of-attack conditions. The investigation shows that these turbulence models provide good comparison with experimental data for attached flow at moderate angle-of-attack conditions. Calculation by current turbulence models are, however, not appropriate at high angle-of-attack conditions with flow separation.

A STUDY ON THE AERODYNAMIC SHAPE DESIGN WITH THE PARSEC FUNCTION (PARSEC 함수를 이용한 헤어포일의 공력 형상 설계 연구)

  • Lee, Jae-Hun;Jung, Kyung-Jin;Kwon, Jang-Hyuk;Ahn, Joong-Ki
    • 한국전산유체공학회:학술대회논문집
    • /
    • 2007.10a
    • /
    • pp.88-91
    • /
    • 2007
  • In the shape design optimization of an airfoil, the shape function has been used to find the optimal airfoil shape for given conditions. The parameters determining the airfoil shape are used in the shape design optimization as design variables. However, they usually don't have physical meaning. The PARSEC (Parametric Shapes) function is a recently proposed shape function and its parameters have the physical meaning. In this study the usefulness of the PARSEC is tested for the RAE2822 airfoil in the transonic flow region to reduce the shock strength and the result is compared with Hicks-Henne function. The optimized airfoils reduce the shock strength and they show similar result.

  • PDF

Numerical Study on Transient Aerodynamics of Moving Flap Using Conservative Chimera Grid Method (보존적 중첩격자기법을 이용한 동적 플랩의 천이적 공력거동에 관한 수치적 연구)

  • Choi S. W.;Chang K. S.;Kim I. S.
    • Journal of computational fluids engineering
    • /
    • v.5 no.2
    • /
    • pp.9-19
    • /
    • 2000
  • Transient aerodynamic response of an airfoil to a moving plane-flap is numerically investigated using the two-dimensional Euler equations with conservative Chimera grid method. A body moving relative to a stationary grid is treated by an overset grid bounded by a 'Dynamic Domain Dividing Line' which has an advantage for constructing a well-defined hole-cutting boundary. A conservative Chimera grid method with the dynamic domain-dividing line technique is applied and validated by solving the flowfield around a circular cylinder moving supersonic speed. The unsteady and transient characteristics of the flow solver are also examined by computations of an oscillating airfoil and a ramp pitching airfoil respectively. The transient aerodynamic behavior of an airfoil with a moving plane-flap is analyzed for various flow conditions such as deflecting rate of flap and free stream Mach number.

  • PDF