• Title, Summary, Keyword: 비정렬 중첩격자 기법

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An Unstructured 3-D Chimera Technique for Overlapped Bodies inRelative Motion (3차원 비정렬 중첩격자계를 이용한 서로 겹쳐진 물체들 간의 상대운동 해석기법에 관한 연구)

  • 안상준;권오준;정문승
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.34 no.8
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    • pp.1-7
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    • 2006
  • In the present study, A 3-D chimera technique for overlapped bodies in relative motion is studied using unstructured meshes. If all node points of a mesh element at solid boundary are in another body, this element is excluded from computational domain. For computation of unsteady flow, non-active cells have proper variables using interpolation and extrapolation. These variables are used in next time step. The motion of a launching trajectory ejected from a wing and the motion of deploying fins of a trajectory which have not been simulated are computed to conform practicality of this technique.

CONSERVATIVE OVERSET MESH TECHNIQUE ON 2-D UNSTRUCTURED MESHES (이차원 비정렬 격자계에서의 보존적 중첩 격자 기법)

  • Jung, M.S.;Kwon, O.J.;Kang, H.J.
    • 한국전산유체공학회:학술대회논문집
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    • pp.27-32
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    • 2008
  • In the present study, a conservative overset mesh technique has been developed on 2-D unstructured meshes. A new domain connection technique between independent mesh blocks was proposed to satisfy the conservation of mass, momentum, or energy in entire computational domain. The present technique was applied to several classical computational problems to validate the superiority of the conservative method to the non-conservative method.

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CONSERVATIVE OVERSET MESH TECHNIQUE ON 2-D UNSTRUCTURED MESHES (이차원 비정렬 격자계에서의 보존적 중첩 격자 기법)

  • Jung, M.S.;Kwon, O.J.;Kang, H.J.
    • 한국전산유체공학회:학술대회논문집
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    • pp.27-32
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    • 2008
  • In the present study, a conservative overset mesh technique has been developed on 2-D unstructured meshes. A new domain connection technique between independent mesh blocks was proposed to satisfy the conservation of mass, momentum, or energy in entire computational domain. The present technique was applied to several classical computational problems to validate the superiority of the conservative method to the non-conservative method.

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Numerical Simulation of Airframe Separation of a Missile System Using an Unstructured Overset Mesh Technique (비정렬 중첩격자기법을 이용한 유도무기의 기체분리운동 모사)

  • Jeong, Mun-Seung;Lee, Sang-Uk;Gwon, O-Jun;Heo, Gi-Hun;Byeon, U-Sik
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.34 no.5
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    • pp.19-29
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    • 2006
  • In this study, numerical simulation of airframes separating from a missile system has been preformed. For the time-accurate trajectory simulation, six D.O.F equations of motion of multiply connected bodies were derived and these equations have been coupled with the unstructured overset mesh technique for the treatment of independent mesh blocks moving with each body component. Applications were made for the simulation of the airframe separation at missile angles of attack of 0 and 5 degrees. It was demonstrated that the present method is efficient and robust for the prediction of unsteady time-accurate flow fields involving multiple bodies in relative motion.

Development of an Unstructured 2-D Chimera Technique for Overlapped Bodies in Relative Motion (2차원 비정렬 중첩격자계를 이용한 서로 겹쳐진 물체간의 상대운동 해석기법 개발)

  • An, Sang-Jun;Gwon, O-Jun;Jeong, Mun-Seung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.34 no.2
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    • pp.17-25
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    • 2006
  • In the present study, a 2-D chimera technique for overlapped bodies in relative motion is developed using unstructured triangular meshes. The solid boundary nodes located next to the intersecting point between bodies are merged to the intersecting point to assure accurate representation of the intersecting region. In order to assign proper value of flow variables at the nodes located out of the computational field, interpolation is conducted for non-active nodes. For validation, the motions of a NACA64A006 airfoil and a NACA0012 airfoil with a plane flap are computed and the results are compared with other simulations. The motion of a launching missile ejected from a NACA0012 airfoil is also simulated.

Development of an Unstructured Parallel Overset Mesh Technique for Unsteady Flow Simulations around bodies with Relative Motion (상대운동이 있는 물체주위의 비정상 유동해석을 위한 병렬화된 비정렬 중첩격자기법 개발)

  • Jung, Mun-Seung;Kwon, Oh-Joon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.2
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    • pp.1-10
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    • 2005
  • An unstructured parallel overset mesh method has been developed for the simulation of unsteady flows around multiple bodies in relative motion. For this purpose, an efficient and robust search method is proposed for the unstructured grid system. A new data-structure is also proposed to handle the variable number of data on parallel sub-domain boundary. The interpolation boundary is defined for data communication between grid systems. An interpolation method to retain second-order spatial accuracy and to treat the points inside the neighboring solid bodies are also suggested. A single store separating from the Eglin/Pylon configuration is calculated and the result is compared with experimental data for validation. Simulation of unsteady flows around multiple bodies in relative motion is also performed.

DEVELOPMENT OF AN UNSTRUCTURED OVERSET MESH METHOD FOR 2-D UNSTEADY VISCOUS FLOW SIMULATION WITH RELATIVE MOTION (상대운동이 있는 이차원 비정상 점성 유동 해석을 위한 비정렬 중첩격자기법 개발)

  • Jung Mun-Seung;Kwon Oh-Joon
    • Journal of computational fluids engineering
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    • v.11 no.2
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    • pp.1-7
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    • 2006
  • An unstructured overset mesh method has been developed for the simulation of unsteady viscous flow fields around multiple bodies in relative motion. For this purpose, a robust and fast search technique is proposed for both triangle and high-aspect ratio quadrilateral cell elements. The interpolation boundary is defined for data communication between grid systems and an interpolation method is suggested for viscous and inviscid cell elements. This method has been applied to calculate the flow fields around 2-D airfoils involving relative motion. Validations were made by comparing the predicted results with those of experiments or other numerical results. It was demonstrated that the present method is efficient and robust for the prediction of unsteady time-accurate flow fields involving multiple bodies in relative motion.

DEVELOPMENT OF AN UNSTRUCTURED OVERSET MESH METHOD FOR 2-D UNSTEADY VISCOUS FLOW ANALYSIS (이차원 비정상 점성 유동 해석을 위한 비정렬 중첩격자기법 개발)

  • Jung M. S.;Kwon O. J.
    • 한국전산유체공학회:학술대회논문집
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    • pp.135-139
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    • 2005
  • An unstructured overset mesh method has been developed for the simulation of unsteady viscous flow fields around multiple bodies in relative motion. For this purpose, a robust and fast search technique is proposed for both triangle and high-aspect quadrilateral cell elements. The interpolation boundary is defined for data communication between grid systems and an interpolation method is suggested for viscous and inviscid cell elements. This method has been applied to calculate the flow fields around 2-D airfoil including relative motion. Validation were made by comparing the predicted results with those of experiments or other researcher's numerical results. It was demonstrated that the present method is efficient and robust for the prediction of unsteady time-accurate flow fields involving multiple bodies in relative motion.

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Ground Effect of a Rotor Blade on a Whirl Tower (훨타워 로터 블레이드의 지면효과)

  • Kang, Hee-Jung;Kim, Seung-Ho
    • Aerospace Engineering and Technology
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    • v.10 no.2
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    • pp.74-81
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    • 2011
  • A numerical simulation is performed to study the ground effect of a rotating rotor blade on a whirl tower using unstructured overset mesh. The aerodynamic change of the rotor blade by the structure around the whirl tower is also considered. The calculated results showed good agreement with the experiment for the hover performance. The ground effect of the rotor blade is investigated by comparing with the calculated results for the out of ground condition and the results of an analytic model.

VISCOUS FLOW ANALYSIS OF UNDERWATER PROPULSOR USING AN UNSTRUCTURED OVERSET MESH TECHNIQUE (비정렬 중첩격자기법을 이용한 수중추진기 주위의 점성유동 해석)

  • An, S.J.;Kwon, O.J.;Jung, Y.P.
    • 한국전산유체공학회:학술대회논문집
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    • pp.341-346
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    • 2010
  • In this paper, viscous flow calculation of pump-jet that is used as underwater propulsor was made by using RANS equation. For the validation, calculation for DTRC4119 marine propeller was made and reasonable agreements were obtained between the present results and the experiment. An unstructured overset mesh technique is used for analysis of relative motion between rotor and stator in pump-jet propulsor. Results for pump-jet propulsor were compared with computational results of another researcher.

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