Hydrodynamic Analysis of Stepped Planning Vessels - Sensitivity Analysis of Loading Condition to Air Breathing of Transvers Steps

Abstract

Main difference between planning vessels, conventional displacement, and semi-displacement marine vessels is in their utilization hydrodynamic loads in addition to buoyancy force. The hydrodynamic pressure field on the bottom surface of planning vessels decreases the vessel draught and the thereafter their resistance. The resistance reduction introduces achieving higher speeds. One of the methods for improving hydrodynamic efficiency of planning vessels is utilization of transverse steps under their bottoms. Selecting their locations and heights has high sensitivity to loading conditions, speed, and center of gravity of the vessel. If proper design does not occur, it maybe followed by un-favorite effects. In this research, the flow field over the bottom of two stepped high speed planning vessels at different lading conditions were obtained, using CFD. VOF method was used for capturing the interface between water and air. Simulation was performed for one-step and two-step planning vessels of Cigar. For validating of the simulations, a grid-independency study and some comparisons with experiments are carried out. The emphasis of this study was on identification of the sensitivity of loading conditions on air-breathing of the transverse steps. The results show that the sensitivity is much higher than the traditional non-stepped planning vessels.  

Keywords

References

  1. Doctors, L.J. “Hydrodynamics of High-speed Small Craft”, Technical Report, University of Michigan, 1985.
  2. Savitsky, D. and Morabito, M. “Surface Wave Contours Associated with the Forebody Wake of Stepped Planing Hulls”, Marine Technology, Vol. 47, No. 1, pp. 1–16, 2010.
  3. Lotfi, P., Ashrafizaadeh, M. and Esfahani, R.K. “Numerical Investigation of A Stepped Planing Hull in Calm Water”, Ocean Eng., Vol. 94, No. 1, pp.103–110, 2015.
  4. Clement, E.P. and Blount, D.L. “Resistance Tests of Systematic Series of Planing Hull Forms”, SNAME Transaction, Vol. 71, No. 1, pp. 491-579, 1963.
  5. Faltinsen, O.M. “Hydrodynamics of High Speed Marine Vehicles”, Cambridge University Press, New York, NY 10011-4211, USA, 2006.
  6. Caponnetto, M. “Practical CFD Simulations for Planing Hulls”, In: The Second International Euro Conference on High Performance Marine Vehicles, Hamburg, pp. 128–138, 2001.
  7. Brizzolara, S. and Serra, F. “Accuracy of CFD Codes in the Prediction of Planing Surfaces Hydrodynamic Characteristics”, The Second International Conference on Marine Research and Transportation. pp. 147–159, 2007.
  8. Savitsky, D. “Hydrodynamic Design of Planing Hulls”, Marine Technology, Vol. 1, No. 1, pp. 71-95, 1964.
  9. Shuford, C.L. “A Theoretical and Experimental Study of Planing Surfaces Including Effects of Cross Section and Plan Form”, NACA Report-1355, 1958.
  10. Ghadimi, P., Tavakoli, S., Dashtimanesh A. and Pirooz, A. “Developing a Computer Program for Detailed Study of Planing Hull’s Spray, Based on Morabito’s Approach”, J. Marine Science and Application, Vol. 13, No. 1, pp. 402-415, 2014.
  11. Garland, W.R. and Maki, K.J. “A Numerical Study of A Two - Dimensional Stepped Planing Surface”, J. Ship Prod. Des., Vol. 28, No. 2, pp. 60–72, 2012.
  12. Tavakoli, M.,Vafaesefat, M., and Seif, M.S. “Hydrodynamic Characteristics of Planning Boat with Variable Dead-raise”, The 13th Marine Industries Conf., Kish, Iran, 2012. (In Persian).
  13. Ghasemi, H. and Bagherzade, M., “Study of Dynamic Stability of Planning Boats Equipped with Interceptor”, The 14th Marine Industries Conf., Tehran, Iran, 2013 (In Persian).
  14. Mansori, M., Ghasemi, H., Mosavizadegan, M. “Trim Control of Planning Boats Using Interceptor”, In: Proceeding of the 11th Marine Industries Conf., Tehran, Iran. (In Persian).
  15. Makasyeyev, M.V. “Numerical Modeling of Cavityflow on Bottom of a Stepped Planing Hull”, The Seventh International Symposium Cavitation, Ann Arbor, Michigan, USA, 2009.
  16. Taunton, D., Hudson, D., and Shenoi, R. “Characteristics of a Series of High Speed Hard Chine Planing Hulls-part 1: Performance in Calm Water”, Int. J. Small Craft Technol., Vol. 152, No. 1, pp. 55–75, 2010.
  17. Wang, S., Su, Y., Zhang, X., and Yang, J. “RANSE Simulation of High-speed Planning Craft in Regular Waves”, J. Marine Science and Application, Vol. 11, No. 1, pp. 447-452, 2012.
  18. Aghajani, A. and Seif, M.S. “Comparison of the Effects of Transverse Steps on Resistance of Planning Boat”, The 15th Marine Industries Conference, Tehran, 2014 (In Persian).

Files

History

  • Receive Date: 27 December 2017
  • Revise Date: 19 February 2019
  • Accept Date: 19 September 2018
  • Publish Date: 22 June 2017

Share

How to cite

Statistics