Experimental and numerical investigations on hydrodynamic and aerodynamic characteristics of the tunnel of planing trimaran. (February 2017)

• Record Type: Journal Article
• Authors: Jiang, Yi; Sun, Hanbing; Zou, Jin; Hu, Ankang; Yang, Jinglei
• Is Part Of: Applied ocean research. Volume 63(2017:Oct.)
• Page Start: 1
• Page End: 10
• Publication Date: 2017-02
• Subjects: Planing trimaran -- Tunnel -- Wave -- Hydrodynamic -- Aerodynamic -- Numerical simulation; Ocean engineering -- Periodicals; 620.416205
• DOI: 10.1016/j.apor.2016.12.009
• Languages: English
• ISSNs: 0141-1187

Abstract

Abstract : Highlights: The tunnel is crucial in adjusting the hydrodynamic behavior of planing trimaran. The high-speed resistance decreases as soon as the tunnel is fully ventilated. 2-DOF motion of planing trimaran in calm water is modeled. The aerodynamic forces provide the major tunnel lift when Fr is above 4.52. The resistance is decreased at the expense of motion stability when the straight section length of tunnel is enlarged. Abstract: The planing trimaran possesses distinctive hybrid hydrodynamic and aerodynamic performance due to the presence of tunnel. The research described in this paper was carried out based on the observation of wave characteristics of a planing trimaran model in towing tests, in which the resistance drops as soon as the wave surface separates from tunnel roof. In order to gain a deeper insight into the relationship between wave flow and forces in tunnel region, a comprehensive series of viscous CFD simulations considering free-surface and 2-DOF motion of the hull (heave and pitch) have been performed for the tested model at the volume based Froude numbers ranging from 3.16 to 5.87. The calculated results were validated by comparison with experimental data and showed good agreement. Numerical results of wave contours, longitudinal wave cuts and lifting force distributions at the calculated speeds were presented for the analysis of ventilation process in tunnel region and the corresponding variation of tunnel forces. It is found that, for the speeds higher than Froude number of 4.52, the aerodynamic forces provide major tunnel lift and mainly act on the straight section of the tunnel. And, therefore, numerical simulations of two modified models have also been performed for the analysis of influence of straight section length on the hydrodynamic and aerodynamic performance of planing trimaran.