Journal of the Korean Society of Marine Environment & Safety (해양환경안전학회지)

The Korean Society of Marine Environment and safety (해양환경안전학회)
권호 표지
DOI QR코드

DOI QR Code

Numerical Study on Roughness Effect for Axi-symmetry Submerged Body in High Reynolds Number

고 레이놀즈 수에서의 축대칭 몰수체의 거칠기에 대한 수치연구

  • Joung, Tae-Hwan (Korea Research Institute of Ships & Ocean Engineering (KRISO), International Cooperation Center) ;
  • Song, Hyung-Do (Korea Research Institute of Ships & Ocean Engineering (KRISO), Offshore Plant Research Division) ;
  • Yum, Jong-Gil (Korea Research Institute of Ships & Ocean Engineering (KRISO), Advanced Ship Research Division) ;
  • Song, Seongjin (Department of Ocean Engineering, Korea Maritime and Ocean University) ;
  • Park, Sunho (Department of Ocean Engineering, Korea Maritime and Ocean University)
  • 정태환 (선박해양플랜트연구소 국제협력실) ;
  • 송형도 (선박해양플랜트연구소 해양플랜트연구부) ;
  • 염종길 (선박해양플랜트연구소 미래선박연구부) ;
  • 송성진 (한국해양대학교 해양공학과) ;
  • 박선호 (한국해양대학교 해양공학과)
  • Received : 2017.12.11
  • Accepted : 2018.04.27
  • Published : 2018.04.30
Download PDF
⟨ Previous Next ⟩

Abstract

In this paper, the friction drag force of 3D submerged body is investigated by considering the surface roughness, the first grid height, and the Reynolds number using open CFD source code, OpenFOAM 4.0. A procedure for estimating drag components by CFD code is set up and suggested in this study. In the 3D submerged body, because of the form factor in the 3D computations, the friction resistance with the small roughness of $12{\mu}m$ obtains different result with the smooth wall. As the Reynolds number increased, the boundary layer becomes thinner and the fiction resistance tends to decrease. In the computations for the effect of y+, the friction resistance and wall shear stress are excessively predicted when the y+ value deviates from the log layer. This is presumably because the boundary layer becomes thicker and the turbulence energy is excessively predicted in the nose due to the increase in y+ value. As the roughness increases, the boundary layer becomes thicker and the turbulence kinetic energy on the surface increases. From this study, the drag estimation method, considering the roughness by numerical analysis for ships or offshore structures, can be provided by using the suggested the y+ value and surface roughness with wall function.

본 논문은 3차원 축대칭 몰수체에 대해 소스 코드가 공개된 OpenFOAM 4.0을 이용하여 첫 번째 격자의 높이와 레이놀즈 수에 따른 마찰저항 변화에 대해 연구하였다. 마찰저항 계산을 위해 경계조건, 수치조건을 정립하였다. 축대칭 물체의 3차원 효과로 인해 거칠기가 매우 작은 $12{\mu}m$에서도 부드러운 표면과 비교해 마찰저항이 다르게 계산되었다. 레이놀즈 수가 커질수록 경계층의 두께 증가가 감소되었으며 이로 인해 마찰저항의 증가량이 감소되었다. 첫 번째 격자의 크기인 y+에 대한 영향에 대해서도 검토하였다. 첫 번째 격자가 log layer에 위치하고 있지 않으면 마찰저항과 표면의 전단력이 과도하게 예측되는 것을 확인하였다. 이는 경계층이 두껍게 예측되어 난류에너지가 과도하게 예측되었기 때문으로 판단된다. 표면의 거칠기가 커질수록 경계층이 두꺼워지고 표면의 난류에너지가 증가되는 것을 확인하였다. 마찰저항을 정확하게 예측하기 위해서는 y+ 값, 거칠기 및 벽함수가 적절한 영역에 위치해야 함을 알 수 있었다.

Keywords

References

  1. Candries, M.(2001), Drag, boundary-layer and roughness characteristics of marine surfaces coated with anti-foulings, PhD. thesis, Department of Marine Technology, University of Newcastle-upon-Tyne, UK.
  2. Candries, M., M. Atlar, E, Mesbahi, and K. Pazouki(2003), The measurement of the drag characteristics of tin-free self-polishing co-polymers and fouling release coatings using a rotor apparatus, Biofouling, Vol. 19, No. 1, pp. 1029-2454.
  3. Chatzikyriakou, D., J. buongiomo, D. Caviezel and D. Lakehal(2015), DNS and LES of turbulent flow in a closed channel featuring a pattern of hemispherical roughness elements, International Journal of Heat and Fluid Flow, Vol. 53, pp. 29-43. https://doi.org/10.1016/j.ijheatfluidflow.2015.01.002
  4. Choi, J. and H. Kim(2010), A Study of using Wall Function for Numerical Analysis of High Reynolds Number Turbulent Flow, Journal of the Society of Naval Architects of Korea, Vol. 47, No. 5, pp. 647-655. https://doi.org/10.3744/SNAK.2010.47.5.647
  5. Coder, D. W.(1983), "Reynolds number scaling of Velocities in Axisymmetric turbulent boundary layers, 14th Symposium Naval Hydrodynamics (ONR), National Academy Press, pp. 1071-1086.
  6. Dassler, P., D. Kozulovic and A. Fiala(2010), Modelling of roughness-induced transition using local variables, V European Conference on Computational Fluid Dynamics, Lisbon, Portugal, 14-17 June.
  7. Flack, K. and M. Schultz(2014), Roughness Effects on Wall-Bounded Turbulent Flows, Physics of Fluids, Vol. 26. p. 101305. https://doi.org/10.1063/1.4896280
  8. Park, S.(2014), Development of numerical towing tank using open source libraries and its application, Journal of the Korean Society of Marine Environment & Safety, Vol. 20, No. 6, pp. 746-751 https://doi.org/10.7837/kosomes.2014.20.6.746
  9. Park, S., S. W. Park, S. H. Rhee, S. B. Lee, J. E. Chi and S. H. Kang(2013), Investigation on the wall function implementation for the prediction of ship resistance, International Journal of Naval Architecture and Ocean Engineering, Vol. 5, pp. 33-46. https://doi.org/10.2478/IJNAOE-2013-0116
  10. Pope, S. B.(2000), Turbulent flows, Cambridge University Press, UK.
  11. Schoenherr, K. E.(1932), On the resistance of flat surfaces moving through a fluid, Naval Architect sand Marine Engineering, Vol. 40, p. 279.
  12. Schultz, M. P. (2004), Frictional resistance of antifouling coating systems, ASME Journal of Fluids Engineering, Vol. 126, No. 6, pp. 1039-1047. https://doi.org/10.1115/1.1845552
  13. Shih, T. H., W. W. Liou, A. Shabbir, Z. Yang and Z. Zhu(1995), A new $k-{\varepsilon}$ eddy-viscosity model for high $\varepsilon$ Reynolds number turbulent flows, Computers & Fluids, Vol. 24, No. 3, pp. 227-238. https://doi.org/10.1016/0045-7930(94)00032-T
  14. Song, S. and S. Park(2017), Numerical analysis of four circular columns in square array and wave interaction, Journal of the Korean Society of Marine Environment & Safety, Vol. 24, No. 5, pp. 558-565.
  15. Van Leer, B.(1979), Towards the Ultimate Conservative Difference Scheme, Journal of Computational Physics, Vol. 32, pp. 101-136. https://doi.org/10.1016/0021-9991(79)90145-1
  16. Walderhaug, H.(1986), Paint roughness effects on skin friction, International Shipbuilding Progress, Vol. 33, pp. 96-100. https://doi.org/10.3233/ISP-1986-3338201
  17. Weiss, J. M., J. P. Maruszewski and W. A. Smith(1999), Implicit Solution of Preconditioned Navier Stokes Equations Using Algebraic Multigrid, AIAA Journal, Vol. 37, pp. 29-36. https://doi.org/10.2514/2.689