Interaction of turbulences with non-breaking divergent waves in an open channel
1
조회
0
다운로드
1
인용
0
참고문헌
키워드
초록
This paper presents a direct numerical simulation of turbulent flows over a bump in an open channel to examine the turbulence characteristics near divergent waves emanating from the bump and to investigate the interaction of the turbulences with the divergent waves. To verify the reliability of the simulations, the mean velocity profile and root-mean-square of velocity fluctuations are compared with previous data. The anisotropic invariant maps show that the ratio of the streamwise to spanwise velocity fluctuations plays an important role in characterizing the anisotropic nature of the separated shear layer behind the bump in the vicinity of the free surface. The vortex identification discloses a large-scale streamwise vortical structure from the mean velocity field and a cluster of small coherent structures from the instantaneous velocity field, which are responsible for the anisotropic characteristics of the turbulence beneath the free surface.
Abstract
This paper presents a direct numerical simulation of turbulent flows over a bump in an open channel to examine the turbulence characteristics near divergent waves emanating from the bump and to investigate the interaction of the turbulences with the divergent waves. To verify the reliability of the simulations, the mean velocity profile and root-mean-square of velocity fluctuations are compared with previous data. The anisotropic invariant maps show that the ratio of the streamwise to spanwise velocity fluctuations plays an important role in characterizing the anisotropic nature of the separated shear layer behind the bump in the vicinity of the free surface. The vortex identification discloses a large-scale streamwise vortical structure from the mean velocity field and a cluster of small coherent structures from the instantaneous velocity field, which are responsible for the anisotropic characteristics of the turbulence beneath the free surface.
참고문헌 (28)
- Antonia, R. A., "Some characteristics of small-scale turbulence in a turbulent duct flow", J. Fluid Mech, 233, pp.369~388 (1991)
- Banerjee, S., "Presentation of anisotropy properties of turbulence, invariants versus eigenvalue approaches", J. Turbul, 8(N32), pp.1~27 (2007)
- Chen, Y. J., "Application of two-phase fluid approach for free-surface ship flow simulation", J. Chin. Inst. Eng, 25, pp.179~188 (2002)
- Handler, R. A., "Transport of a passive scalar at a shear-free boundary in fully developed turbulent open channel flow", Phys. Fluids, 11, pp.2607~2625 (1999)
- Kim, S. E., "Evaluation of an URANS-LES hybrid approach for turbulent free surface flows around surface-piercing bodies", 9th International Conference on Numerical Ship Hydrodynamics (2007)
- Kim, J., "Wall pressure fluctuations and flow-induced noise in a turbulent boundary layer over a bump", J. Fluid Mech, 558, pp.79~102 (2006)
- Kim, J., "Turbulence statistics in fully developed channel flow at low Reynolds number", J. Fluid Mech, 177, pp.133~166 (1987)
- Komori, S., "Direct numerical simulation of threedimensional open-channel flow with zero-shear gas-liquid interface", Phys. Fluids, 5, pp.115~125 (1993)
- 구본국, "Reynolds and froude number effect on the flow past an interface-piercing circular cylinder", International Journal of Naval Architecture and Ocean Engineering, 6(3), pp.529~561 (2014), 대한조선학회
- Le, H., "Direct numerical simulation of turbulent flow over a backward-facing step", J. Fluid Mech, 330, pp.349~374 (1997)
- Lee, J., "Structures of turbulent open-channel flow in the presence of an air-water interface", J. Turbul., 13(N18), pp.1~18 (2012)
- Lumley, J. L., "The return to isotropy of homogeneous turbulence", J. Fluid Mech, 82, pp.161~178 (1977)
- Mansour, N. N., "Reynolds-stress and dissipation-rate budgets in a turbulent channel flow", J. Fluid Mech, 194, pp.15~44 (1988)
- Marquillie, M., "Direct numerical simulation of a separated channel flow with a smooth profile", J. Turbul, 9(N1), pp.1~23 (2008)
- Mollicone, J. P., "Effect of geometry and Reynolds number on the turbulent separated flow behind a bulge in a channel", J. Fluid Mech, 823, pp.100~133 (2017)
- Na, Y., "Direct numerical simulation of a separated turbulent boundary layer", J. Fluid Mech, 374, pp.379~405 (1998)
- Nagaosa, R., "Direct numerical simulation of vortex structures and turbulent scalar transfer across a free surface in a fully developed turbulence", Phys. Fluids, 11, pp.1581~1595 (1999)
- Nagaosa, R., "Statistical analysis of coherent vortices near a free surface in a fully developed turbulence", Phys. Fluids, 15, pp.375~394 (2003)
- Ozdemir, Y. H., "Numerical and experimental study of turbulent free surface flow for a fast ship model", Brodogranja, 65(1), pp.39~54 (2014)
- Dong Woo Park, "The sensitivity of ship resistance to wall-adjacent grids and near-wall treatments", International Journal of Naval Architecture and Ocean Engineering, 10(6), pp.683~691 (2018), 대한조선학회
- 박선호, "Investigation on the wall function implementation for the prediction of ship resistance", International Journal of Naval Architecture and Ocean Engineering, 5(1), pp.33~46 (2013), 대한조선학회
- Rhee, S. H., "Unsteady Reynolds averaged Navier-Stokes method for freesurface wave flows around surface-piercing cylindrical structures", J. Waterw. Port. C, 135(4), pp.135~143 (2009)
- Seo, J. H., "Free Surface Effects on Turbulent Boundary Layer and Near-Wake Around a Surface-Piercing Body", Ph.D, pp.2016
- 설동명, "Towed underwater PIV measurement for free-surface effects on turbulent wake of a surface-piercing body", International Journal of Naval Architecture and Ocean Engineering, 5(3), pp.404~413 (2013), 대한조선학회
- Suh, J., "The effect of air-water interface on the vortex shedding from a vertical circular cylinder", J. Fluid Struct, 27, pp.1~22 (2011)
- Ubbink, O., "A method for capturing sharp fluid interfaces on arbitrary meshes", J. Comput. Phys, 153, pp.26~50 (1999)
- Xing, T., "Unsteady free-surface wave-induced separation: analysis of turbulent structures using detached eddy simulation and single-phase level set", J. Turbul, 8(N44), pp.1~35 (2007)
- Zwart, P. J., "Simulation of unsteady freesurface flow around a ship hull using a fully coupled multi-phase flow method", J. Mar. Sci. Technol, 13, pp.346~355 (2008)