Overlapping Grid Technique for Numerical Simulation of a Fast-Cruising Catamaran Fitted with Active T-Foils

Abstract

In marine engineering, appendages such as fin stabilizers and/or T-foils are made to rotate and to reduce the motion of ships. Research on the hydrodynamics of ships fitted with active appendages has significantly improved the design and control of such ships. However, most studies focus on fixed rather than rotating appendages, thereby ignoring the hydrodynamic unsteadiness of active appendages. To enhance the reliability and precision of the numerical simulations, we propose the use of overlapping grids for simulating advanced catamarans fitted with a pair of rotating T-foils under each bow. The fundamental purpose of the overlapping grid technique is to realize information exchange via regional overlap sharing in each subdomain of the computing domain, instead of using the method of boundary sharing, thus greatly alleviating the difficulty of generating the subdomain grid; moreover, the technique guarantees the quality of the subdomain grid. Within the main computational domain, a subdomain was allocated to accommodate the T-foil. Overlapping meshes near the interface between the two domains enable information flow during the simulation; the overlapping grids are updated at every iteration step because the subdomain rotates. The instantaneous trim and sinkage responses of the catamaran to the T-foil rotation were reproduced. From the moment the active T-foil stopped moving, there was no change in the ship’s sailing attitude, indicating that the response was in real time. By comparing with EFD data, the numerical results showed reasonable agreement, indicating the feasibility and effectiveness of the technique in simulating the hydrodynamics of ships fitted with active appendages.

Keywords

Overlapping grids / Numerical simulation / Active appendages / T-foil / Catamaran

References

[1] Chen QR, Ye HK, Guan YM. Hydrodynamic analysis of 3-D hydrofoil under free surface in time domain. J Ship Mech, 2010, 14(12): 1331-1339

[2] Deng R, Huang DB, Zhou GL (2014) Research on the influence of T-foil on the hydrodynamic performance of trimaran. The Twenty-fourth International Ocean and Polar Engineering Conference, Busan. 758–763,

[3] Esteban S, Giron-Sierra JM, Andres-Toro BD, Dela Cruz JM. Fast ships models for seakeeping improvement studies using flaps and T-foil. Math Comput Model, 2005, 41(1): 1-24

[4] Feng WL, Li J, Zhang W. Numerical simulation of airfoil icing based on deformation grid. J Northwest Polytech Univ, 2008, 26(5): 550-555 (in Chinese)

[5] Hao HB, Guo ZQ, Ma QW, Dai SS (2015) A preliminary study on the hydrodynamic propulsive force of a pair of inversely oscillating hydrofoils. The twenty-fifth international offshore and polar engineering conference. 1040-1045, Kona, Hawaii, USA

[6] Ji HT, Chen JR, Li W. Several measures of ship aft modification. China Ship Res, 2006, 1(3): 41-46 (Journals in Chinese)

[7] Jiang Y, Sun HB, Zou J, Yang DM, Hu AK. Influence of angle-variable stern flap on resistance performance of stepped planing hull. J Shanghai Jiaotong Univ, 2016, 320-325(in Chinese): 3

[8] Jin MX, Zhang JN, Zhang L, Jin MY. Influence of speedboat stern pressure plate on hydrodynamic performance of speedboat. China Water Transp, 2015, 07: 9-10 (in Chinese)

[9] Kehoe JW, Brower KS, Meier HA, Runnerstro CE. U. S. and foreign hull form, machinery, and structure design practices. Nav Eng J, 1983, 95(6): 36-53

[10] Liang H (2015) Lifting theories for wing-in-ground effect and hydrofoils in the vicinity of a free surface. PhD thesis, Dalian University of Technology, Dalian. 23–25

[11] Liang LH, Jiang JL, Zhang ST (2013) Improving the vertical motion of wave piercing catamaran using T-foil. ICMA 2013 (8):1481–1485. https://doi.org/10.1109/ICMA.2013.6618132

[12] Liu YH (2014) The research of T-foil and flap’s effect on wave-piercing catamaran seakeeping. Master thesis, China Ship Research Institute, Beijing. 25–30

[13] Liu AL (2016) The influence of spray rails and stern flat on planning hull resistance performance. Master thesis, Harbin Engineering University, Harbin, 25–43

[14] Liu YH, Wang GY, Wang Q, Chai X, Ren WL. Influence of T-foil on wave resistance of wave-piercing catamaran. China Water Transp, 2016, 2: 12-13 (in Chinese)

[15] Ma C (2012) The effect of interceptor stern flap on the resistance of planning boat. Master thesis, Harbin Engineering University, Harbin: 41–59

[16] Ning P (2017) Prediction of hydrodynamic performance on three-dimensional hydrofoil and propeller using potential panel method. Master thesis, Zhejiang University, Zhejiang, 47–60

[17] Nirschl H. Overlapping grids for the simulation of particle interaction at the micro scale. China Particuol, 2005, 3(1–2): 60-67

[18] Piperno S. Explicit/implicit fluid/structured staggered procedures with a structural prediction and fluid subcycling for 2D inviscid aeroelastic simulation. Int J Numer Meth Fluids, 1997, 25: 1207-1226

[19] Shao SM, Wang YC. The effects of stern trimming flap on resistance of high speed craft. Shipbuild China, 1981, 01: 29-39 (in Chinese)

[20] Si HL, Yu H, Li ZJ, Geng YC, Hu JJ. The research of slamming pressure impacted on wave suppression board. Ship Sci Technol, 2015, 02: 19-23 (in Chinese)

[21] Wang TC (2017) Research on hydrodynamic characteristics of an oscillating foil near free surface. Master thesis, Harbin Engineering University, Harbin. 42–65

[22] Yang Q (2012) Research on the design of T-foil for trimaran. Master thesis, Harbin Engineering University, Harbin 23–25

[23] Yang Q, Lin Z, Guo ZQ. Theoretical analysis and simulation on anti-rolling effect of trimaran fitted T foil. J Cent South Univ (Sci Technol), 2013, 44(2): 46-51 (in Chinese)

[24] Yang JL, Yang DM, Li P, Lin Z. Numerical analysis of peak resistance reduction by bubbly layer for surface effect ship. J Harbin Eng Univ, 2017, 38(11): 1709-1714

[25] Zhang LP, Deng XG, Zhang HX. Moving mesh generation and unsteady calculation methods study. Adv Mech, 2007, 40(4): 424-447 (in Chinese)

[26] Zhao FM, Gao CJ, Xia Q. Overlap grid research on the application of ship CFD. J Ship Mech, 2011, 15(4): 332-341 (in Chinese)