Side Wall Effects on the Hydrodynamics of a Floating Body by Image Green Function Based on TEBEM

Abstract

A novel numerical model based on the image Green function and first-order Taylor expansion boundary element method (TEBEM), which can improve the accuracy of the hydrodynamic simulation for the non-smooth body, was developed to calculate the side wall effects on first-order motion responses and second-order drift loads upon offshore structures in the wave tank. This model was confirmed by comparing it to the results from experiments on hydrodynamic coefficients, namely the first-order motion response and second-order drift load upon a hemisphere, prolate spheroid, and box-shaped barge in the wave tank. Then, the hydrodynamics of the KVLCC2 model were also calculated in two wave tanks with different widths. It was concluded that this model can predict the hydrodynamics for offshore structures effectively, and the side wall has a significant impact on the first-order quantities and second-order drift loads, which satisfied the resonant rule.

Keywords

Taylor expansion boundary element method / Side wall effects / Image Green function / Hydrodynamics / Sharp corner floating body

References

[1] Chen X. On the side wall effects upon bodies of arbitrary geometry in wave tank. Appl Ocean Res, 1994, 16(6): 337-345

[2] Chen J. Numerical simulation on the second-order hydrodynamic problems based on the Taylor expansion boundary element method. PhD thesis. Harbin Engineering University, 2015, China: Harbin, (in Chinese)

[3] Clément A (1979) Contribution à l’étude théorique et expérimentale des mouvements de corps flottants induits par une houle régulière an profondeur finie uniforme. PhD thesis, Université de Nantes, ECN, Nantes, France

[4] Dai Y, Duan W. Potential flow theory of ship motions in waves, 2008, Beijing: National Defense Industry Press, 63-65 (in Chinese)

[5] Duan W (2012) Taylor expansion boundary element method for floating body hydrodynamics. Proceeding of the 27th International Workshop on Water Waves and Floating Bodies. Copenhagen, Denmark

[6] Duan W, Chen J, Zhao B. Second-order Taylor expansion boundary element method for the second-order wave radiation problem. Appl Ocean Res, 2015, 52: 12-26

[7] Duan W, Chen J, Zhao B. Second-order Taylor expansion boundary element method for the second-order wave diffraction problem. Eng Anal Bound Elem, 2015, 58: 140-150

[8] Duan W, Chen J, Zhao B. Calculation of second-order mean drift loads for the deepwater floating body based on the Taylor expansion boundary element method. J Harbin Eng Univ, 2015, 36(3): 302-306 in Chinese)

[9] Kashiwagi M (1988) Theoretical prediction of tank wall effects on hydrodynamic forces acting on an oscillating and translating slender ship. Proceeding of the 4th International Workshop on Water Waves and Floating Bodies, Oslo, Norway, 105–109

[10] Kashiwagi M. 3-D integral-equation method for calculating the effects of tank-wall interference on hydrodynamic forces acting on a ship. J Kansai Society Nav Architects Jpn, 1989, 212(0): 89-101

[11] Kashiwagi M. Radiation and diffraction forces acting on an offshore-structure model in a towing tank. Int J Offshore Polar Eng, 1991, 1(2): 101-107

[12] McIver P. The wave field scattered by a vertical cylinder in a narrow wave tank. Appl Ocean Res, 1993, 15(1): 25-37

[13] Newman JN (2016) Channel wall effects in radiation-diffraction analysis. Proceeding of the 31st International Workshop on Water Waves and Floating Bodies, Plymouth, MI, USA

[14] Shao Y (2010) Numerical potential-flow studies on weakly-nonlinear wave-body interactions with/without small forward speeds. PhD thesis, Department of Marine Technology, NTNU, Norway

[15] Xia J. Evaluation of the green function for 3-D wave-body interactions in a channel. J Eng Math, 2001, 40(1): 1-16

[16] Xu G, Duan W. Numerical investigation of second-order wave diffraction based on the Rankine source method. J Harbin Eng Univ, 2010, 31(9): 1144-1152 in Chinese)

[17] Zhao R, Faltinsen OM (1989) Interaction between current, waves and marine structures, 5th International Conference on Numerical Ship Hydrodynamics, Washington D.C.

[18] Zhu L, Dai Y. The singular behavior of potential flow around the rectangular corners of floating bodies. Acta Mech Sinica, 1993, 25(1): 116-122 in Chinese)

[19] Zhu L, Dai Y. The singular behavior in vicinity of intersection between the body and free surface. Appl Math Mech, 1993, 14(5): 459-468