Modeling Three-dimensional Free Surface Flow around Thin Wall Incorporation Hydrodynamic Pressure on δ-coordinate

• Journal title : Journal of Wetlands Research
• Volume 16, Issue 3,  2014, pp.327-336
• Publisher : Korean Wetlands Society
• DOI : 10.17663/JWR.2014.16.3.327
Title & Authors
Modeling Three-dimensional Free Surface Flow around Thin Wall Incorporation Hydrodynamic Pressure on δ-coordinate
Kim, Hyo-Seob; Yoo, Ho-Jun; Jin, Jae-Yul; Jang, Chang-Hwan; Lee, Jung-Su; Baek, Seung-Won;

Abstract
Submerged thin walls are extreme case of submerged rectangular blocks, and could be used for many purposes in rivers or coastal zones, e.g. to tsunami. To understand flow characteristics including flow and pressure fields around a specific submerged thin wall a numerical model was applied which includes computation of hydrodynamic pressure on $\small{{\sigma}}$-coordinate. $\small{{\sigma}}$-coordinate has strong merits for simulation of subcritical flow over mild-sloped beds. On the other hand $\small{{\sigma}}$-coordinate is quite poor to treat sharp structures on the bed. There have been a few trials to incorporate dynamic pressure in $\small{{\sigma}}$-coordinate by some researchers. One of the previous approaches includes process of sloving the Poisson equation. However, the above method includes many high-order terms, and requires long cpu for simulation. Another method SOLA was developed by Hirt et al. for computation of dynamic pressure, but it was valid for straight grid system only. Previous SOLA was modified for $\small{{\sigma}}$-coordinate for the present purpose and was adopted in a model system, CST3D. Computed flow field shows reasonable behaviour including vorticity is much stronger than the upstream and downstream of the structure. The model was verified to laboratory experiments at a 2DV flume. Time-average flow vectors were measured by using one-dimensional electro-magnetic velocimeter. Computed flow field agrees well with the measured flow field within 10 % error from the speed point of view at 5 profiles. It is thought that the modified SOLA scheme is useful for $\small{{\sigma}}$-coordinate system.
Keywords
CST3D;Sigma Coordinate;Hydrodynamic pressure;
Language
Korean
Cited by
References
1.
Bin, L., Chris A.F., 2003. Three-dimensional hydrodynamic model for free surface flow. International Association of Hydraulic Research, Vol. 41, No 4. pp. 367-377.

2.
Flow Science., 2003. Flow-3D. Theory manual. Los Alamos, NM.

3.
Fluent Inc., 2005. Manual. Lebanon, NH 3766.

4.
Hirt, C.W., Nichols, B.D., 1975. SOLA-A Numerical Solution Algorithm for Transient Fluid Flows. Losa Alamos, NM.

5.
Kim, H., Lee, J., Jin, J., and Jang, C., 2013. A Practical Algorithm to Simulate Erosion of On-Shore Zone. J. of Wetlands Research, Vol. 15, No. 3, pp. 423-430.[Korean Literature]

6.
Louis, A,H., David, M.Y., 1981. Applied lterative Method, Academic Press, New York.

7.
Madala, R.A., Piacsek, S.A., 1977. A semi-implicit numerical model for baroclinic oceans, J. of Computational Physics, Vol. 23, Issue 2, PP. 167-178.

8.
Musteyde, B.K., Roger, A.F., Lin .B., 2002. Three-dimensional numerical modeling of free surface flows with non-hydrostatic pressure. International J. for Numerical Methods In Fluids, Vol. 40, pp. 1145-1162.

9.
Pengzhi, L., 2006. A multiple-layer $\sigma$-coordinate model for simulation of wave structure interaction. Computer & Fluids 35, pp. 147-167.

10.
Pengzhi, L., 2002. A $\sigma$-coordinate three-dimensional numerical model for surface wave propagation. International J. for Numerical Methods In Fluids, Vol. 38, pp. 1045-1068.

11.
Smagorinsky, J., 1963. General circulation experiments with the primitive equations, Part I: the basic experiment. Mon. Wea. Rev, 91, PP. 99-164.

12.
Tetra tech., 2007a. The Environmental Fluid Dynamic Code User Manual US EPA Version 1.01, Tetra Tech, Inc.