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In this study, a high-speed planing trimaran hull form is designed, and the effects of different displacements and gravity longitudinal layouts on the performance of the trimaran planing hull in calm water are experimentally investigated in the towing tank of the China Special Vehicle Research Institute. Based on previous work, an innovative inner tunnel appendage hydroflap is mounted in the inner aft tunnel, located 1/8 L from the transom in the longitudinal direction with attack angles of 0° and 4°, respectively. Furthermore, a regular stern flap is mounted on the transom close to the chine. The towing test results show that, as the gravity center moves forward, the high-speed region resistance of the planing trimaran increases and the longitudinal stability is also strengthened. Further, the total resistance of the planing trimaran with a heavier displacement is larger while the average mass resistance declines; i.e., the resistance efficiency is improved. The results also indicate that the inner tunnel hydroflap and stern flap enhance the aft hull hydrodynamic lift and tunnel aerodynamic lift. As a result, mounting aft hull lift enhancement appendages can affect the bottom and inner tunnel pressure distribution and then cause a slight resistance decrease in the low-speed region. The value relationship of resistance between groups of appendages for the attached hull and bare hull is reversed at a speed of about Froude number 3.0. Although the aft hull lift enhancement appendages result in a higher resistance cost in the high-speed region, the longitudinal stability is effectively promoted and the occurrence speed of porpoising results in a delay of 1 to 2 m/s.
Jin Zou; Shijie Lu; Hanbing Sun; Liru Zan; Jiuyang Cang. Experimental Study on Motion Behavior and Longitudinal Stability Assessment of a Trimaran Planing Hull Model in Calm Water. Journal of Marine Science and Engineering 2021, 9, 164 .
AMA StyleJin Zou, Shijie Lu, Hanbing Sun, Liru Zan, Jiuyang Cang. Experimental Study on Motion Behavior and Longitudinal Stability Assessment of a Trimaran Planing Hull Model in Calm Water. Journal of Marine Science and Engineering. 2021; 9 (2):164.
Chicago/Turabian StyleJin Zou; Shijie Lu; Hanbing Sun; Liru Zan; Jiuyang Cang. 2021. "Experimental Study on Motion Behavior and Longitudinal Stability Assessment of a Trimaran Planing Hull Model in Calm Water." Journal of Marine Science and Engineering 9, no. 2: 164.
The planing trimaran is a novel kind of aerodynamic alleviated marine vehicle and possesses a unique hybrid hydrodynamic and aerodynamic characteristics. In this paper, to investigate the hull behavior of a planing trimaran under the effect of tunnel forces, the tunnel and demihull are treated as appendages mounted on the slender main hull. Numerical simulations were carried out for planing trimaran and a monohull which was built according to the main hull configuration. Mesh convergence studies were implemented based on the public experimental data of a similar planing trimaran. Calculated results show that the presence of tunnel and demihull could decrease the resistance of the main hull and improve the longitudinal motion stability at high speeds. Flow evolutions of waves, velocity vector, wetted length and lift distribution were performed to explain the variation of the tunnel lift and its moment and their influence on hull behavior. Parameter studies on demihull length were carried out as well. It was found that, as the demihull length is increased, the tunnel trimming moment would decrease especially in the final stage of ventilation, making resistance reduced but the motion stability weakened.
Hanbing Sun; Jin Zou; Zhiyuan Sun; Shijie Lu. Numerical Investigations on the Resistance and Longitudinal Motion Stability of a High-Speed Planing Trimaran. Journal of Marine Science and Engineering 2020, 8, 830 .
AMA StyleHanbing Sun, Jin Zou, Zhiyuan Sun, Shijie Lu. Numerical Investigations on the Resistance and Longitudinal Motion Stability of a High-Speed Planing Trimaran. Journal of Marine Science and Engineering. 2020; 8 (11):830.
Chicago/Turabian StyleHanbing Sun; Jin Zou; Zhiyuan Sun; Shijie Lu. 2020. "Numerical Investigations on the Resistance and Longitudinal Motion Stability of a High-Speed Planing Trimaran." Journal of Marine Science and Engineering 8, no. 11: 830.
In the current hydrodynamic research relating to planing hulls, the stern flap and steps are generally considered to be two independent resistance reduction measures. Limited research has focused on the coupled effects of flaps and steps. Therefore, experimental and numerical simulation methods are carried out in this paper to explore the influence of the flap mounting angle coupled with the steps. A series of model towing tests were implemented for a double-stepped planing hull with 2°, 3° and 4.5° flap angles. The test results show that, as the mounting angle increased, the low speed resistance performance was improved and the porpoising critical speed was delayed, with a slight resistance cost. Based on the tests, a numerical simulation method was established with volume Froude numbers ranging from 0.88 to 5.20. The simulated hull flow field showed good agreement with the testing data. The simulation results suggest a cavity induces the negative pressure after the steps; the cavity core region is the air phase, and this expands with the air–water mixture flow. The cavity also causes wetted surface reduction and pressure distribution changes. Finally, comparisons of cavities after-steps and load coefficients of different planing surfaces among models were considered. Numerical results analysis gave distinct interpretations for the experimental phenomenon of porpoising critical speed increasing with a slight resistance increment.
Jin Zou; Shijie Lu; Yi Jiang; Hanbing Sun; Zhuangzhuang Li; Zou; Lu; Sun; Li. Experimental and Numerical Research on the Influence of Stern Flap Mounting Angle on Double-Stepped Planing Hull Hydrodynamic Performance. Journal of Marine Science and Engineering 2019, 7, 346 .
AMA StyleJin Zou, Shijie Lu, Yi Jiang, Hanbing Sun, Zhuangzhuang Li, Zou, Lu, Sun, Li. Experimental and Numerical Research on the Influence of Stern Flap Mounting Angle on Double-Stepped Planing Hull Hydrodynamic Performance. Journal of Marine Science and Engineering. 2019; 7 (10):346.
Chicago/Turabian StyleJin Zou; Shijie Lu; Yi Jiang; Hanbing Sun; Zhuangzhuang Li; Zou; Lu; Sun; Li. 2019. "Experimental and Numerical Research on the Influence of Stern Flap Mounting Angle on Double-Stepped Planing Hull Hydrodynamic Performance." Journal of Marine Science and Engineering 7, no. 10: 346.
The Partial Air Cushion Supported Catamaran (PACSCAT) is an innovative design which combines both the characteristics of hovercraft and catamaran. Further, it provides a high-speed and efficient solution with excellent performance, particularly for shallow water. In this paper, experimental and numerical method are carried out for research of motion attitude and resistance characteristics, which provide a reference for further research and hull optimization work. By model towing test and data interpretation, and the resistance, trim, and heave varying law with increasing speed is summarized. From the view of total resistance, the impacts of the cushion pressure and air flow on resistance performance of PACSCAT are analyzed. Based on the theory of viscous fluid mechanics, a numerical simulation method with high prediction accuracy is established. The flow field around and inside the hull is simulated, the simulating results show good agreements with the testing data. Finally, the effect of the cushion compartment improving the resistance performance is studied. The results show that the cushion compartment is significant for adjusting the pressure distribution of the air cushion. And the average resistance reduction ratio at the high-speed segment can even reach 22%.
Shijie Lu; Jin Zou; Yuangang Zhang; Zhiqun Guo. Experimental and Numerical Study on Motion and Resistance Characteristics of the Partial Air Cushion Supported Catamaran. Water 2019, 11, 1033 .
AMA StyleShijie Lu, Jin Zou, Yuangang Zhang, Zhiqun Guo. Experimental and Numerical Study on Motion and Resistance Characteristics of the Partial Air Cushion Supported Catamaran. Water. 2019; 11 (5):1033.
Chicago/Turabian StyleShijie Lu; Jin Zou; Yuangang Zhang; Zhiqun Guo. 2019. "Experimental and Numerical Study on Motion and Resistance Characteristics of the Partial Air Cushion Supported Catamaran." Water 11, no. 5: 1033.