Lagrangian Dynamic Smagronsky 난류모형과 SPH를 이용한 쇄파역에서의 비선형 천수거동에 관한 연구
Numerical Analysis of Nonlinear Shoaling Characteristics over Surf ZoneUsing SPH and Lagrangian Dynamic Smagronsky Model
0
조회
0
다운로드
3
인용
0
참고문헌
키워드
초록
단조해안에서의 비선형 천수거동을 가장 강건한 파랑모형인 Navier Stokes 식에 기초하여 수치모의 하였다. 이와 더불어 SUPERTANK LABORATORY DATA COLLECTION PROJECT (Krauss et al., 1992)에서 취득한 자료를 활용하여 Reynolds 응력에 대한 구배모형의 한계를 검증하였다. 취득한 쇄파대 유동계의 자기상관함수는 상당한 특성길이를 지니며 이러한 결과는 구배모형이 큰 오류를 야기할 수 있다는 사실을 시사한다. 이러한 인식에 기초하여 파랑모형은 Large Eddy Simulation (LES), Smooth Particle Hydrodynamics (SPH), Gaussian kernel function을 사용하여 수치 적분하였다. 잔차응력은 Lagrangian Dynamic Smagronski 모형 (Meneveau et al., 1996)을 활용하여 모의하였으며 모의 기간 중 유체 알갱이간의 이격거리는 관성부영역의 특성길이보다 작게 유지되도록 노력하였다. 천수과정에서 진행되는 동조•비동조 고차 조화성분으로 전이된 파랑에너지로 인해 상당히 예리하고 왜도된 파형, 파형의 마루로부터 시작되는 물입자 자유낙하, 착수로 인한 커다란 물보라의 형성, 물보라 형성층의 해변으로의 이행, wave finger (Narayanaswamy와 Darlymple, 2002) 등이 비교적 정확히 재현되는 등 상당히 고무적인 결과를 얻었다.
Abstract
Nonlinear shoaling characteristics over surf zone are numerically investigated based on spatially averaged Navier Stokes equation. We also test the validity of gradient model for turbulent stresses due to wave breaking using the data acquainted during SUPERTANK LABORATORY DATA COLLECTION PROJECT (Krauss et al., 1992). It turns out that the characteristics length scale of breaking induced current is not negligible, which firmly stands against ever popular gradient model, model, but favors Large Eddy Simulation with finer grid. Based on these observations, we model the residual stress of spatially averaged Navier Stokes equation after Lagrangian Dynamic Smagorinsky (Meneveau et al., 1996). We numerically integrate newly proposed wave equations using SPH with Gaussian kernel function. Severely deformed water surface profile, free falling water particle, queuing splash after landing of water particle on the free surface and wave finger due to structured vortex on rear side of wave crest (Narayanaswamy and Dalrymple, 2002) are successfully duplicated in the numerical simulation of wave propagation over uniform slope beach, which so far have been regarded very difficult features to mimic in the computational fluid mechanics.
참고문헌 (23)
- "1967. An Introduction to Fluid Dynamics", Cambridge Univ. Press
- "SPH Modeling of water waves" (2000)
- Dalrymple, R.A.,, "Using a Lagrangian particle method for deck overtopping", pp.1082~1091 (2001)
- Dalrymple, R.A., "Numerical modeling of water waves with the SPH method", 53, pp.141~147 (2006)
- Dean, "1991. Water wave mechanics for engineers and scientists"
- Elgar S.,, "Nearshore sandbar migration", 106, pp.11~ (2001)
- A, "theory and application to nonspherical stars", pp.375~389 (1977)
- GomezGesteira, M.,, "Green water overtopping analyzed with a SPH medel", 32, pp.223~238 (2005)
- Kraus, "Proceedings of the 23rd Coastal Engineering Conference", pp.2191~2204
- A.N, "1942. The equations of turbulent motion in an incompressible fluid. Izvestia Acad. Sci.", pp.56~58
- Lucy, "1977. A numerical approach to the testing of the fission hypothesis. Astronomical Journal 82"
- Menevenau, C.,, "A Lagrangian dynamic subgridscale model of turbulence", 319, pp.353~385 (1996)
- Monaghan J.J, "1994. Simulating free surface flows with SPH. Journal of Computational Physics 110", pp.399~406
- Morris, J.P.,, "Modeling low Reynolds number incompressible flows using SPH", 136, pp.214~226 (1997)
- Narayanaswamy, M., "An experimental study of surface instabilities during wave breaking", pp.344~355 (2002)
- Peregrine, "bores and hydraulic jumps. Proc. of 16th ICCE", pp.540~550 (1978)
- Pope, Stephen B, "Ten questions concerning the largeeddy simulation of turbulent flows", 6(35), pp.1~24 (2004)
- Rodi, "1993. Turbulence models and their application in hydraulics a state of art review International Association for Hydraulic Research"
- J, "1963. General circulation experiments with primitive equations", 91, pp.99~164, Smagorincky
- Takeda, "1994. Numerical simulation of viscous flow by smoothed particle hydrodynamics. Progress in Theoretical Physics 92", and mi(ru), pp.939~959
- H, "1992. A first course in turbulence The MIT Press"
- Veeramony, J., "Modeling the flow in surf zone waves", (CACR9904) (1999), Center for applied coastal research, Univ. of Delaware, Newark, Delaware
- Yoshizawa, "1986. Statistical theory for compressible turbulent shear flows with application to subgrid modeling Physics of Fluids A 29", pp.2152~2164