Journal of Mechanical Science and Technology

The Korean Society of Mechanical Engineers (대한기계학회)
권호 표지

Flow Around a Pipeline and Its Stability in Subsea Trench

  • Lee, Seungbae (Department of Mechanical Engineering, Inha University) ;
  • Jang, Sung-Wook (Department of Mechanical Engineering, Inha University) ;
  • Chul H. Jo (Department of Naval Architecture and Ocean Engineering, Inha University) ;
  • Hong, Sung-Guen (Department of Naval Architecture and Ocean Engineering, Inha University)
  • Published : 2001.04.01
Download PDF
⟨ Previous Next ⟩

Abstract

Offshore subsea pipelines must be stable against external loadings, which are mostly due to waves and currents. To determine the stability of a subsea pipeline on the seabed, the Morrison equation has been applied with prediction of inertia and drag forces. When the pipeline is placed in a trench, the force acting on it is reduced considerably. Therefore, to consider the stability of a pipeline in a trench, one must employ reduction factors. To investigate the stability of various trenches, we numerically simulated flows over various trenches and compared them with experimental data from PIV (Particle Image Velocimetry) measurements. The present results were produced ar Reynolds numbers ranging from 6$\times$10$^3$to 3$\times$10(sub)5 based on the diameter of the cylinder. Quasi-periodic flow patterns computed by large-eddy simulation were compared with experimental data in terms of mean flow characteristics fro typical trench configurations (W/H=1 and H/D=3, 4). The stability for various trench conditions was addressed in terms of mean amplitudes of oscillating lift and drag, and the reduction factor for each case was suggested for pipeline design.

Keywords

References

  1. Knolll, D.A., Herbich, J.B., 1980, 'Wave and Current Forces on a Submerged Offshore Pipeline,' Offshore Technology Conference, pp. 227-234
  2. Garrison, C.J., 1980, 'A Review of Drag and Inertia Forces on Circular Cylinders,' Offshore Technology Conference. pp. 205-218
  3. Sumer, B.M., 1997, Hydrodynamics Around Circular Structures, Advanced Series on Ocean Engineering-Vol. 12, World Scientific
  4. Smagorinsky, J., 1963, 'General Circulation Experiments with the Primitive Equations, Part I ; the Basic Experiment,' Monthly Weather Rev., Vol. 91, pp. 99-164 https://doi.org/10.1175/1520-0493(1963)091<0099:GCEWTP>2.3.CO;2
  5. Germano, M., Piomelli, U., Main, P. and Cabot, W. H., 1990, 'A Dynamic Subgrid-Scale Eddy Viscosity Model,' Physics of Fluids A., Vol. 3, pp. 1760-1765
  6. Jordan, S.A., Ragab, S.A., 1998, 'A Large-Eddy Simulation of the Near Wake of a Circular Cylinder,' J. of Fluids Eng., Vol. 120, pp. 243-252
  7. Lee, S., Meecham, W.C, 1996, 'Computation of Noise from Homogeneous Turbulence and a Free Jet,' Int'l J. Acoust. and Vib., Vol. 1, pp. 35-47
  8. Runchal, A.K., Bhatia, S.K., 1993, 'ASME Benchmark Study: ANSWER Predictions for Backward Facing Step and Lid-driven Cubical Cavity,' ASME, FED-Vol. 160, pp. 43-54
  9. Runchal, A.K., 1987, 'CONDlF: A Modified Central-Difference Scheme for Convective Flows,' lnt'l J. Num. Methods in Eng., Vol. 24, pp. 1593-1608 https://doi.org/10.1002/nme.1620240814
  10. Lee, S., Runchal, A.K., Han, J.-O., 1999, 'Subgrid-scale Model in Large-Eddy Simulation and Its Application to Flow about Yawed Cylinder and Cavity Flows,' 3rd ASME/JSME Joints Fluids Eng. Conf., San Francisco
  11. Hayder, M.E., Turkel, E., 1995, 'Nonreflecting Boundary Conditions for Jet Flow Computations,' AIAA J., Vol. 33, No. 12, pp. 2264-2270
  12. Raffel, M., Willert, C.E. and Kompenhans, J., 1998, Particle Image Velocimetry, Springer
  13. Tracy, M.B., Plentovich, E. B., 1997, 'Cavity Unsteady-Pressure Measurements at Subsonic and Transonic Speeds,' NASA Technical Paper, 3669