• Title/Summary/Keyword: 3-D numerical computation

Search Result 131, Processing Time 0.041 seconds

Study on the Experiment and Numerical Computation of Forced Convection Heat Transfer around Circular Cylinder in a Rectangular Duct (사각덕트 내에서 원형 실린더 주위의 강제대류 열전달에 대한 실험과 수치계산에 관한 연구)

  • 윤영환;김경환
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.16 no.5
    • /
    • pp.490-498
    • /
    • 2004
  • This paper measures the forced convective heat transfer from heated cylinder to air flow in a rectangular duct at Re$_{D}$ =2,337, 4,589, 6,621 and 7,944 through experiments. And the heat transfer is computed by 3-D numerical computation in which various turbulent models are applied. It is shown through the comparison of experimental and computed data that numerical computation with standard k-$\varepsilon$ model predicts the experimental data most accurately. Furthermore, the correlation from the computed heat transfer is almost similar to that from the experiment when Re$_{D}$ is greater than 4,589. In addition, the correlation of McAdams is the closest to that from experimental data among various correlations from literature in the range of Reynolds number.ber.

The comparison between Numerical Computation and Experiment on Fluid Elow in Rectangular Duct (사각덕트내의 유체유동에 관한 수치계산과 실험의 비교)

  • Yoon Young-Hwan;Bae Taeg-Hee;Park Won-Gu
    • Proceedings of the KSME Conference
    • /
    • 2002.08a
    • /
    • pp.71-74
    • /
    • 2002
  • Fluid flow in a rectangular duct system are measured by W laser doppler velocity meter, and also computed by commercial software of STAR-CD for comparison between then First, for a rectangular duct with 90 degree metered elbow, the fluid flow with Reynolds numbs's of 1,508 is predicted by assumption of both laminar and turbulent models. But, even though the Reynolds number is less than 2,300-3,000, the computation by turbulent model is close to the experimental data. Moeover, the computation by turbulent model for Reynolds number of 11,751 also predicts the experimental data satisfactorily. Second, for a rectangular duct with two branch ducts, the ratios between flow rates in the two branches are invariant to Reynolds number according to both of numerical and experimental results.

  • PDF

3D numerical simulation of temperature on Pilot tube

  • Ying Wang;Baogeng Ding
    • 한국전산유체공학회:학술대회논문집
    • /
    • 2006.05a
    • /
    • pp.248-251
    • /
    • 2006
  • Multi-physics problem is considered for the Pitot tube located in uniform freon gas flow with high Mach number and the 3D numerical results of temperature on Pitot tube is given. The model is created by using structural module of ANSYS, the grids are obtained by ICEM, and the problem is solved and the data post-processing is done by CFX.

  • PDF

Analysis of Three-dimensional Nonaxisymmetric Spin-up by Using Parallel Computation (병렬계산에 의한 비축대칭 3차원 스핀업 유동해석)

  • Park, Jae-Hyoun;Choi, Yoon-Hwan;Suh, Yong-Kweon
    • Proceedings of the KSME Conference
    • /
    • 2001.06e
    • /
    • pp.512-517
    • /
    • 2001
  • In this study, spin-up flows in a rectangular container are analysed by using three-dimensional computation. In the numerical computation, we use the parallel computer system of PC-cluster type. We compared our results with those obtained by two-dimensional computation. Effect of velocity and vorticity on the flow is studied. The result shows that two-dimensional solution is in good agreement with the 3-D result. Attention is given to the region where the 3-D flow is significant.

  • PDF

Comparison of fully coupled hydroelastic computation and segmented model test results for slamming and whipping loads

  • Kim, Jung-Hyun;Kim, Yonghwan;Korobkin, Alexander
    • International Journal of Naval Architecture and Ocean Engineering
    • /
    • v.6 no.4
    • /
    • pp.1064-1081
    • /
    • 2014
  • This paper presents a numerical analysis of slamming and whipping using a fully coupled hydroelastic model. The coupled model uses a 3-D Rankine panel method, a 1-D or 3-D finite element method, and a 2-D Generalized Wagner Model (GWM), which are strongly coupled in time domain. First, the GWM is validated against results of a free drop test of wedges. Second, the fully coupled method is validated against model test results for a 10,000 twenty-foot equivalent unit (TEU) containership. Slamming pressures and whipping responses to regular waves are compared. A spatial distribution of local slamming forces is measured using 14 force sensors in the model test, and it is compared with the integration of the pressure distribution by the computation. Furthermore, the pressure is decomposed into the added mass, impact, and hydrostatic components, in the computational results. The validity and characteristics of the numerical model are discussed.

3-D Numerical Study on a Oblique Jet Impingement for Fluid flows and Heat Transfer Characteristics Using ${\kappa}-{\varepsilon}-\bar {{\upsilon}'^ 2}$ Model (${\kappa}-{\varepsilon}-\bar {{\upsilon}'^ 2}$ 모델을 이용한 경사진 충돌제트의 유동장 및 열전달 특성에 대한 3차원 수치해석적 연구)

  • Choi, Bong-Jun;Lee, Jung-Hee;Choi, Young-Ki
    • Proceedings of the KSME Conference
    • /
    • 2000.04b
    • /
    • pp.789-794
    • /
    • 2000
  • The Paper studies the flow and heat transfer characteristics to a jet impinging at different oblique angles, to a plane surface by numerical methods. The flowfield and heat transfer rate associated with the oblique Impingement of an axisymmetric jet are of interest as a result of its presence in numerous technological Problems. For the computation of heat transfer rate, the standard ${\kappa}-{\varepsilon}$ and ${\kappa}-{\varepsilon}-\bar {{\upsilon}'^ 2}$ turbulent model were adapted. The accuracy of the numerical calculations was compared with various experimental data reported in the literature. ${\kappa}-{\varepsilon}-\bar {{\upsilon}'^ 2}$ model showed better agreement with experimental data than standard ${\kappa}-{\varepsilon}$ model in prediction of the turbulent intensity and the heat transfer rate. In the case of computation of flowfield, the study carries on the ${\alpha}=45$ deg, h/D=4.95. The jet Reynolds number based on the nozzle diameter(D), was 48,000. For the computation of heat transfer rate, the Re=20,000, the jet orifice-to-plate spacings(L/D) are 4, 6 and 10, and the angle between the axis of the jet orifice and the plate surface is set at 30, 45, 60, or 90 deg. For the smaller spacings, the near-peak Nusselt numbers are not significantly effected by the initial decreases in the Jet angle. The overall shape of the local Nusselt number x-axis profile is influenced by both the jet orifice-to-plate spacing and the jet angle.

  • PDF

Numerical flow computation around aeroelastic 3D square cylinder using inflow turbulence

  • Kataoka, Hiroto;Mizuno, Minoru
    • Wind and Structures
    • /
    • v.5 no.2_3_4
    • /
    • pp.379-392
    • /
    • 2002
  • Numerical flow computations around an aeroelastic 3D square cylinder immersed in the turbulent boundary layer are shown. Present computational code can be characterized by three numerical aspects which are 1) the method of artificial compressibility is adopted for the incompressible flow computations, 2) the domain decomposition technique is used to get better grid point distributions, and 3) to achieve the conservation law both in time and space when the flow is computed a with moving and transformed grid, the time derivatives of metrics are evaluated using the time-and-space volume. To provide time-dependant inflow boundary conditions satisfying prescribed time-averaged velocity profiles, a convenient way for generating inflow turbulence is proposed. The square cylinder is modeled as a 4-lumped-mass system and it vibrates with two-degree of freedom of heaving motion. Those blocks which surround the cylinder are deformed according to the cylinder's motion. Vigorous oscillations occur as the vortex shedding frequency approaches cylinder's natural frequencies.

A Numerical Study on the Improvement of Performance for the 2 Vane Pump Impeller (2 Vane 펌프 임펠러의 성능 개선에 관한 수치해석적 연구)

  • KIM, SUNG;MA, SANG-BUM;CHOI, YOUNG-SEOK;KIM, JIN-HYUK
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.31 no.3
    • /
    • pp.293-301
    • /
    • 2020
  • This paper describes a numerical study on the improvement of performance of the 2 vane pump impellers. The design of these impellers was optimized using a commercial computation fluid dynamics code and design of experiments. Geometric design variables were defined by the impeller blade angle distribution. The objective functions were defined as the total head, total efficiency and solid material size of the impellers. The importance of the geometric design variables was analyzed using 2k factorial designs. The interaction between the total head, total efficiency and solid material size, according to the impeller blade angle distribution, is discussed by analyzing the 2k factorial design results.

Construction Algorithm of Grassmann Space Parameters in Linear Output Feedback Systems

  • Kim Su-Woon
    • International Journal of Control, Automation, and Systems
    • /
    • v.3 no.3
    • /
    • pp.430-443
    • /
    • 2005
  • A general construction algorithm of the Grassmann space parameters in linear systems - so-called, the Plucker matrix, 'L' in m-input, p-output, n-th order static output feedback systems and the Plucker matrix, $'L^{aug}'$ in augmented (m+d)-input, (p+d)-output, (n+d)-th order static output feedback systems - is presented for numerical checking of necessary conditions of complete static and complete minimum d-th order dynamic output feedback pole-assignments, respectively, and also for discernment of deterministic computation condition of their pole-assignable real solutions. Through the construction of L, it is shown that certain generically pole-assignable strictly proper mp > n system is actually none pole-assignable over any (real and complex) output feedbacks, by intrinsic rank deficiency of some submatrix of L. And it is also concretely illustrated that this none pole-assignable mp > n system by static output feedback can be arbitrary pole-assignable system via minimum d-th order dynamic output feedback, which is constructed by deterministic computation under full­rank of some submatrix of $L^{aug}$.

A Particle Tracking Method for the Lagrangian-Eulerian Finite Element Method in 3-D Subsurface System (3차원 지표하 시스템에서 Lagrangian-Eulerian 유한요소법에 대한 입자추적 알고리즘)

  • Lee, Jae-Young;Kang, Mee-A
    • The Journal of Engineering Geology
    • /
    • v.19 no.2
    • /
    • pp.205-215
    • /
    • 2009
  • The conventional numerical models to analyze flow in subsurface porous media under the transient state usually generate numerical oscillation and unstability due to local flux domain for critical cases such as infiltration into initially dry soil during rainfall period. In this case, it is required refined mesh and small time step, but it decrease efficiency of computation. In this study, numerical unstability in discontinuity domain is removed by applying particle tracking algorithm to simulate unsteady subsurface flow with inflow boundary condition. Finally the hybrid LE FEM improving numerical stability is proposed. The hypothetical domains with unsteady uniform and nonuniform flow field were used to demonstrated algorithm verification. In comparison with analytic solution, we obtained reasonable results and conducted simulation of hypothetical 3-D recharge/pumping area. The proposed algorithm can simulate saturated/unsaturated porous media with more practical problems and will greatly contribute to accuracy and stability of numerical computation.