• 제목/요약/키워드: P2P1 element

검색결과 704건 처리시간 0.027초

P2P1 유한요소를 이용한 비압축성 Navier-Stokes 방정식 해법들의 행렬 특성 (CHARACTERISTICS OF MATRICES IN THE P2P1 FINITE ELEMENT METHODS FOR SOLVING THE INCOMPRESSIBLE NAVIER-STOKES EQUATION)

  • 조명환;최형권;유정열
    • 한국전산유체공학회:학술대회논문집
    • /
    • 한국전산유체공학회 2009년 춘계학술대회논문집
    • /
    • pp.245-251
    • /
    • 2009
  • Numerical algorithms for solving the incompressible Navier-Stokes equations using P2P1 finite element are compared regarding the eigenvalues of matrices. P2P1 element allocates pressure at vertex nodes and velocity at both vertex and mid nodes. Therefore, compared to the P1P1 element, the number of pressure variables in the P2P1 element decreases to 1/4 in the case of two-dimensional problems and to 1/8 in the three-dimensional problems. Fully-implicit-integrated, semi-implicit- integrated and semi-segregated finite element formulations using P2P1 element are compared in terms of elapsed time, accuracy and eigenvlue distribution (condition number). For the comparison,they have been applied to the well-known benchmark problems. That is, the two-dimensional unsteady flows around a fixed circular cylinder and decaying vortex flow are adopted to check spatial accuracy.

  • PDF

유체-구조물 상호작용을 위한 유한요소 결합공식화의 예조건화에 대한 연구 (Preconditioning Method of a Finite Element Combined Formulation for Fluid-Structure Interaction)

  • 최형권
    • 대한기계학회논문집B
    • /
    • 제33권4호
    • /
    • pp.242-247
    • /
    • 2009
  • AILU type preconditioners for a two-dimensional combined P2P1 finite element formulation of the interaction of rigid cylinder with incompressible fluid flow have been devised and tested by solving fluid-structure interaction (FSI) problems. The FSI code simulating the interaction of a rigid cylinder with an unsteady flow is based on P2P1 mixed finite element formulation coupled with combined formulation. Four different preconditioners were devised for the two-dimensional combined P2P1 finite element formulation extending the idea of Nam et al., which was proposed for the preconditioning of a P2P1 mixed finite element formulation of the incompressible Navier-Stokes equations. It was found that PC-III or PC-IV among them perform well with respect to computational memory and convergence rate for some bench-mark problems.

P2P1 유한요소를 이용한 LES (Large Eddy simulation using P2P1 finite element formulation)

  • 최형권;남영석;유정열
    • 대한기계학회:학술대회논문집
    • /
    • 대한기계학회 2001년도 춘계학술대회논문집E
    • /
    • pp.386-391
    • /
    • 2001
  • A finite element code based on P2P1 tetra element has been developed for the large eddy simulation (LES) of turbulent flows around a complex geometry. Fractional 4-step algorithm is employed to obtain time accurate solution since it is less expensive than the integrated formulation, in which the velocity and pressure fields are solved at the same time. Crank-Nicolson method is used for second order temporal discretization and Galerkin method is adopted for spatial discretization. For very high Reynolds number flows, which would require a formidable number of nodes to resolve the flow field, SUPG (Streamline Upwind Petrov-Galerkin) method is applied to the quadratic interpolation function for velocity variables, Noting that the calculation of intrinsic time scale is very complicated when using SUPG for quadratic tetra element of velocity variables, the present study uses a unique intrinsic time scale proposed by Codina et al. since it makes the present three-dimensional unstructured code much simpler in terms of implementing SUPG. In order to see the effect of numerical diffusion caused by using an upwind scheme (SUPG), those obtained from P2P1 Galerkin method and P2P1 Petrov-Galerkin approach are compared for the flow around a sphere at some Reynolds number. Smagorinsky model is adopted as subgrid scale models in the context of P2P1 finite element method. As a benchmark problem for code validation, turbulent flows around a sphere and a MIRA model have been studied at various Reynolds numbers.

  • PDF

Lp error estimates and superconvergence for finite element approximations for nonlinear parabolic problems

  • LI, QIAN;DU, HONGWEI
    • Journal of the Korean Society for Industrial and Applied Mathematics
    • /
    • 제4권1호
    • /
    • pp.67-77
    • /
    • 2000
  • In this paper we consider finite element mathods for nonlinear parabolic problems defined in ${\Omega}{\subset}R^d$ ($d{\leq}4$). A new initial approximation is taken. Optimal order error estimates in $L_p$ for $2{\leq}p{\leq}{\infty}$ are established for arbitrary order finite element. One order superconvergence in $W^{1,p}$ for $2{\leq}q{\leq}{\infty}$ are demonstrated as well.

  • PDF

FINITE VOLUME ELEMENT METHODS FOR NONLINEAR PARABOLIC INTEGRODIFFERENTIAL PROBLEMS

  • Li, Huanrong;Li, Qian
    • Journal of the Korean Society for Industrial and Applied Mathematics
    • /
    • 제7권2호
    • /
    • pp.35-49
    • /
    • 2003
  • In this paper, finite volume element methods for nonlinear parabolic integrodifferential problems are proposed and analyzed. The optimal error estimates in $L^p\;and\;W^{1,p}\;(2\;{\leq}\;p\;{\leq}\;{\infty})$ as well as some superconvergence estimates in $W^{1,p}\;(2\;{\leq}\;p\;{\leq}\;{\infty})$ are obtained. The main results in this paper perfect the theory of FVE methods.

  • PDF

D. melanogaster에 있어서 P Element를 이용한 rosy 유전자의 형질전환 (P Element-Mediated Transformation with the rosy Gene in Drosophila melanogaster)

  • 김욱
    • 한국동물학회지
    • /
    • 제38권3호
    • /
    • pp.340-347
    • /
    • 1995
  • D. melanogaster를 대상으로 두 종류의 P element construct, 즉 Pc[(ry+)B]와 p[(ry+)$\Delta$SX9]을 사용한 형질전환 실험을 통하여 자율적 및 비자율적인 P element construct간의 vector로써의 효율성을 분석했다. 자율적인 P element 내에 rosy 유전자를 포함하고 있는 Pc[(ry+)B] construct를 진정 M 계통형인 ry506 돌연변이 계통에 주입시켰다. 또한 비자율적인 P element 내에 rosy 유전자를 포함하고 있는 p[(ry+)$\Delta$SX9] construct와 전이효소의 공급원으로써 p-$\Delta$2-3hs$\pi$ helper plasmid를 역시 같은 계통의 ry506 돌연변이 계통에 주입시켰다. Dechorination 방법에 의해 총 1143 embryo를 대상으로 microinjection 한 결과, 모두 35 계통의 형질전환된 정상형의 눈을 가진 계통을 얻었다. P element construct를 주입시킨 전체 1143 embryo 중에서 약 20% 정도가 성체로 부화되었으며, 부화된 개체 가운데 약 40% 정도가 눈 색깔이 거의 정상형과 같은 G0 transformant 로 나타났다. 그러나 생식력을 가진 G0 transformant의 약 40% 만이 G1 transformant로 나타남으로써 모두 35 계통의 transformant를 얻었다. 따라서 G0 단계에서 나타난 형질전환 현상에는 반드시 rosy transformant의 염색체 삽입에 의해서 만이 아니라 세포질내에서도 construct내의 rosy 유전자의 발현이 가능한 것으로 분석되었다. 또한 형질전환율에 있어서는 Pc[(ry+)B]와p[(ry+)$\Delta$SX9] construct 간에 유의한 차가 없는 것으로 나타났다. 이상의 결과로 볼 때, 실험 목적에 따라 자율적인 P element 또는 helper DNA를 이용한 비자율적인 P element를 효과적인 vector 로 선택 이용함으로써 특정 유전자를 곤충집단내로 침투 및 고정시킬 수 있다고 판단된다.

  • PDF

P2P1/P1P1 유한요소 공식을 이용한 비압축성 Navier-Stokes 방정식의 분리 해법에 대한 연구 (STUDY ON THE SPLITTING ALGORITHMSOF THE INCOMPRESSIBLE NAVIER-STOKES EQUATIONS USING P1P1/P2P1 FINITE ELEMENT FORMULATION)

  • 조명환;최형권;유정열;박재인
    • 한국전산유체공학회:학술대회논문집
    • /
    • 한국전산유체공학회 2005년도 추계 학술대회논문집
    • /
    • pp.117-124
    • /
    • 2005
  • Splitting algorithms of the incompressible Navier-Stokes equations using P1P1/P2P1 finite element formulation are newly proposed. P1P1 formulation allocates velocity and pressure at the same nodes, while P2P1 formulation allocates pressure only at the vertex nodes and velocity at both the vertex and mid nodes. For comparison of the elapsed time and accuracy of the two methods, they have been applied to the well-known benchmark problems. The three cases chosen are the two-dimensional steady and unsteady flows around a fixed cylinder, decaying vortex, and impinging slot jet. It is shown that the proposed P2P1 semi-splitting method performs better than the conventional P1P1 splitting method in terms of both accuracy and computation time.

  • PDF

P1P1/P2P1 유한요소 공식을 이용한 배압축성 Navier-Stokes 방정식의 분리 해법에 대한 연구 (Study on the Segregation Algorithms of the Incompressible Navier-Stokes Equations Using P1P1/P2P1 Finite Element Formulation)

  • 최형권;유정열;박재인;조명환
    • 대한기계학회논문집B
    • /
    • 제30권3호
    • /
    • pp.262-269
    • /
    • 2006
  • Segregation algorithms of the incompressible Wavier-Stokes equations using P1P1/P2P1 finite element formulation are newly proposed. P1P1 formulation allocates velocity and pressure at the same nodes, while P2P1 formulation allocates pressure only at the vertex nodes and velocity at both the vertex and the midpoint nodes. For a comparison of both the elapsed time and the accuracy between the two methods, they have been applied to the well-known benchmark problems. The three cases chosen are the two-dimensional steady and unsteady flows around a fixed cylinder, decaying vortex, and impinging slot jet. It is shown that the proposed P2P1 semi-segregation algorithm performs better than the conventional P1P1 segregation algorithm in terms of both accuracy and computation time.

Analysis of Promoter Elements for Transcriptional Expression of Rat p53 Gene in Regenerating Liver

  • Lee, Min-Hyung;Song, Hai-Sun;Park, Sun-Hee;Choi, Jin-Hee;Yu, Sun-Hee;Park, Jong-Sang
    • BMB Reports
    • /
    • 제32권1호
    • /
    • pp.45-50
    • /
    • 1999
  • We previously found three transcription factor-binding motifs in the rat p53 promoter. They are two recognition motifs of NF1-like protein (NF1-like element 1: -296 ~ -312, NF1-like element 2: -195 ~ -219) and a bHLH protein binding element (-142 ~ -146). In this study, we investigated the DNA-protein complex formation of the three elements with nuclear extracts from both normal and regenerating liver to find the element involved in the induced transcription of p53. The level of each DNA-protein complex on NF1-like and bHLH motifs was not changed. Instead, a new element located at -264 ~ -284 was detected in the DNase I footprinting assay with regenerating nuclear extract. This element has partial homology to the AP1 consensus motif. However, the competition studies with diverse oligonucleotides suggest that the binding protein is not AP1. An in vitro transcription assay shows that this element is important for the transcriptional activation of the rat p53 promoter. Therefore, for the induced transcription of the rat p53 promoter, the-264 ~ -284 region is required in addition to two NF1-like and one bHLH motif.

  • PDF

[ $L_p$ ] ERROR ESTIMATES AND SUPERCONVERGENCE FOR FINITE ELEMENT APPROXIMATIONS FOR NONLINEAR HYPERBOLIC INTEGRO-DIFFERENTIAL PROBLEMS

  • Li, Qian;Jian, Jinfeng;Shen, Wanfang
    • Journal of the Korean Society for Industrial and Applied Mathematics
    • /
    • 제9권1호
    • /
    • pp.17-29
    • /
    • 2005
  • In this paper we consider finite element methods for nonlinear hyperbolic integro-differential problems defined in ${\Omega}\;{\subset}\;R^d(d\;{\leq}\;4)$. A new initial approximation of $u_t(0)$ is taken. Optimal order error estimates in $L_p$ for $2\;{\leq}\;p\;{\leq}\;{\infty}$ are established for arbitrary order finite element. One order superconvergence in $W^{1,p}$ for $2\;{\leq}\;p\;{\leq}\;{\infty}$ are demonstrated as well.

  • PDF