Abstract
The blended approach has the potential to provide the engineering solutions for design optimization keeping in view the current demand of the extensive computer resources for fully nonlinear computations. This study investigates two-dimensional boundary value problem for multi-bodies radiation and diffraction velocity of multi-hulled vessels using blended method. In blended scheme, fully nonlinear Euler equations of motion are solved with nonlinear hydrodynamic forces acting on multi-hulled vessels. Lid is employed over the body segment to suppress the eigenvalue mode, thus eliminating singularities in source strength being used on multi-hull bodies presenting geometrical discontinuities. Comparison between the blended technique and its validation against analytical calculations and experimental work are presented and found in good agreement. It is concluded that blended technique is an efficient and accurate alternate method to provide time simulations of ship motion and other essential parameters for design optimization.
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Abbreviations
- U :
-
Mean forward speed
- x, y, z :
-
Inertial coordinate system
- \({\eta_{1}}\) :
-
Surge
- \({\eta_{2}}\) :
-
Sway
- \({\eta_{3}}\) :
-
Heave
- \({\eta_{4}}\) :
-
Roll
- \({\eta_{5}}\) :
-
Pitch
- \({\eta_{6}}\) :
-
Yaw
- x 0 :
-
X-axis in earth fixed coordinate
- t 0 :
-
Time in earth fixed coordinate
- n j :
-
Unit normal
- F :
-
Force
- S :
-
Surface/segment
- \({\Phi}\) :
-
Total velocity potential
- \({\nabla}\) :
-
Laplace operator
- D :
-
Total/cumulative derivative
- \({\varphi}\) :
-
Perturbation velocity potential
- V :
-
Ship unsteady oscillatory velocity vector
- u,v,w :
-
Subscripts used for velocity in x, y and z directions
- \({\xi}\) :
-
Instantaneous wave profile
- p :
-
Total pressure
- \({\kappa}\) :
-
Wave number
- \({\beta}\) :
-
Heading angle
- Z :
-
Complex points on the body surface
- Z o :
-
Complex points in the fluid water domain
- \({\sigma R, D}\) :
-
Constant source strength
- n :
-
Inward normal
- A i,j , B i,j :
-
Added mass and damping coefficients
- d :
-
Damping
- m :
-
Added mass
- N :
-
Calculated numerically
- O :
-
Experimental data
- b :
-
Node points on the body
- r :
-
Complex data (gain)
- i :
-
Complex data (imaginary)
References
Newman J.N.: The theory of ship motions. Adv. Appl. Mech. 18, 221–283 (1978)
Frank, W.: Oscillation of cylinder in or below the free surface of deep fluids. Technical Report, Hydrodynamics Laboratory Research and Development. (1967)
Faltinsen, O.: A Rational Strip Theory of Ship Motions Part II. Ph.D. thesis, University of Michigan. (1971)
Froude W.: On the rolling of ships. RINA 2, 180–229 (1861)
Kriloff A.: A new theory of the pitching motion of ships on waves, and of the stresses produced by this motion. RINA 37, 326–368 (1896)
Vugts, Ir.J.H.: The hydrodynamics coefficients for swaying, heaving and rolling cylinders in a free surface. Technical Report 112 s, Shipbuilding Laboratory, Technological University Delft. (1996)
Liapis S.: Numerical methods for water-wave radiation problem. Int. J. Numer. Methods Fluids 15, 83–97 (1992)
Newman J.N.: Wave effects on multiple bodies. Appl. Ocean Res. 16(1), 47–59 (1994)
Ohkusu M.: On the heaving motion of two circular cylinders on the surface of a fluid. In: Kashiwagi, M. (ed.) Hydrodynamics in Ship and Ocean Engineering, pp. 147–165. Midori Printing Co., Ltd., Fukuoka (2001)
Ohkusu M.: On the motion of multi-hull ships in waves (i). In: Kashiwagi, M. (ed.) Hydrodynamics in Ship and Ocean Engineering, pp. 167–193. Midori Printing Co., Ltd., Fukuoka (2001)
Bal S., Kinnas S.A.: A BEM for the prediction of free surface effects on cavitating hydrofoils. Comput. Mech. 28, 260–274 (2002)
Bal S.: Prediction of wave pattern and wave resistance of surface piercing bodies by a boundary element method. Int. J. Numer. Methods Fluids 56, 305–329 (2008)
Uslu Y., Bal S.: Numerical prediction of wave drag of 2-D and 3-D bodies under or on a free surface. Turk. J. Eng. Environ. Sci. 32, 177–188 (2008)
Bulgarelli U.P., Lugni C., Landrini M.: Numerical modeling of free surface flows in ship hydrodynamics. Int. J. Numer. Methods Fluids 43, 465–481 (2003)
Dubrovsky, V.; Matveev, K.: New types of sea-going multi-hull ships with superior comfort level and safety. (2005)
Troesch A.W.: The diffraction forces for a ship moving in oblique seas. JSR 23, 127–139 (1979)
Wehausen, J.V.; Laitone E.V.: Surface waves. In: Flügge, S. (ed) Encyclopedia of Physics, vol. IX, pp. 446–778. Springer-Verlag, Berlin (1960)
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Khalid, M.S., Nisar, S. & Troesch, A. Radiation and Diffraction Velocity Potentials for Multi-hulled Vessels in 2-D. Arab J Sci Eng 41, 4573–4582 (2016). https://doi.org/10.1007/s13369-016-2184-5
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DOI: https://doi.org/10.1007/s13369-016-2184-5