Bolong Liu

National University of Defense Technology

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Dibo Pan

National University of Defense Technology

Xiaojun Xu

National University of Defense Technology

Xiaojun Xu

National University of Defense Technology

Xiaocong Wang

Guangzhou Education Bureau

Tong Cai

Chongqing Normal University

Yifan Zhang

National University of Defense Technology

Yikun Feng

National University of Defense Technology

Haijun Xu

National University of Defense Technology

Congnan Yang

National University of Defense Technology

Shengyang Lu

National University of Defense Technology

Cooperative Institutions

National University of Defense Technology

Chongqing Normal University

Anhui University of Technology

Fifth Affiliated Hospital of Zhengzhou University

Second Affiliated Hospital of Zhengzhou University

Shenyang University of Technology

Shanghai Electric (China)

State Grid Corporation of China (China)

Hebei Science and Technology Department

Electric Power Research Institute

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Experimental and CFD investigation on resistance reduction of hydrofoils for amphibious vehicles

Ships and Offshore Structures (2024)

Dibo Pan Bolong Liu Xiaojun Xu Xiaocong Wang

Resistance characteristics of amphibious vehicles are crucial for their sailing speed and battlefield survivability. This study proposes the installation of hydrofoils at the wheel cavity to reduce resistance and enhance performance. Two hydrofoil designs and four shapes are analyzed to determine the optimal drag reduction design. Towing tests and numerical simulations are employed to investigate and evaluate the hydrodynamic performance of amphibious vehicles. The impact of hydrofoils on resistance reduction is analysed and elucidated through a comprehensive analysis of surface pressure distribution, sailing attitude, and energy consumption in the flow field. Results demonstrate that, except for the elongation-hydrofoil, the other three shapes all show significant performance optimisation at medium to high speeds Fr>0.5, with improved effectiveness as speed increases. Among the four shapes, the curve-hydrofoil exhibits the best overall drag reduction effect (18%) and resistance peak compression ability (6.68%), owing to its ample lift force and optimal trim capability.

10.1080/17445302.2024.2317634

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Citations (0)

Resistance reduction optimization of an amphibious transport vehicle

Ocean Engineering (2023)

Bolong Liu Xiaojun Xu Dibo Pan

Latin Hypercube Sampling

Solver

Towing

Surrogate model

10.1016/j.oceaneng.2023.114854

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Citations (10)

Drag reduction design and research of high-speed amphibious vehicle’s deformable track wheels

Ships and Offshore Structures (2022)

Bolong Liu Xiaojun Xu Dibo Pan Yikun Feng Shengyang Lu

In this study, the resistance characteristics of the amphibious vehicle in the transitional stage are studied. A deformable track wheel is designed and its effect on the amphibious vehicle's resistance is studied. The numerical calculation method based on the RANS solver and the towing test method is used to analyse the hydrodynamic performance of the amphibious vehicle. Based on the comparison of the vehicle model with no wheel, the influence of wheels on additional resistance at the groove fault is studied. The inclination angles of the front and rear deformation wheels are studied respectively. The influence and principle of the track wheel configuration on drag are analysed and expounded in terms of pressure distribution, water climbing and spray on the wheel grooves, and the hull attitude. Finally, an adjustment strategy of the deformable configuration wheel in the transition stage is proposed.

Towing

Trim

10.1080/17445302.2022.2093032

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Citations (7)

Influence of Flanks on Resistance Performance of High-Speed Amphibious Vehicle

Journal of Marine Science and Engineering (2021)

Dibo Pan Xiaojun Xu Bolong Liu

In order to reduce the additional resistance of high-speed amphibious vehicles, Flanks are designed on the concave grooves. As a new drag reduction attachment, the principle of Flanks is analyzed and discussed in detail. In this paper, the HSAV model and Flanks coupling resistance tests are performed based on the Reynolds-averaged Navier–Stokes method and SST k−ω model. The accuracy of the numerical approach is verified by a series of towing tests. Results show that with a fixed installation angle and invariable characteristic parameters, Flanks can significantly reduce the total resistance at high speed, with a maximum drag reduction of 16%. In the meantime, Flanks also affect the attitude and flow field of the vehicle, consequently affecting the resistance composition and the sailing condition. A vehicle model self-propulsion test is designed and carried out, and it qualitatively verifies the drag reduction effect of the Flanks at high speed.

Towing

10.3390/jmse9111260

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Citations (17)

Research on launching, water exiting, and river crossing of an amphibious vehicle

Physics of Fluids (2023)

Bolong Liu Xiaojun Xu Dibo Pan

The main focus of this paper is the amphibious vehicle's water-land trans-media capability, specifically its ability to efficiently carry out transportation tasks in rivers and nearshore areas. This capability relies on three key processes: launching, water exiting, and river crossing. To study these processes, hydrodynamic numerical simulations are conducted. The Reynolds-averaged Navier–Stokes) equation, simplified terra mechanics model, and body force method are adopted to analyze the trans-media and self-propulsion processes. Results indicate that the optimal launching speed is around 15 km/h, with a stable trim and heave, and a launching angle range of 15°–25° for insubmersibility and stability. Furthermore, high-speed water exiting enhances insubmersibility and imposes lower requirements on road adhesion conditions, outperforming low-speed water exiting. In terms of self-propelled river crossing, higher heading angles and faster river currents improve hydrodynamic lift, with the fastest crossing achieved at a 10° heading angle for a current speed of 2.5 m/s and a forward speed of 30 km/h.

Trim

Lift (data mining)

10.1063/5.0174148

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Citations (1)

Influence of resistance due to locomotion mechanism configurations of a new high-speed amphibious vehicle (HSAV-Ⅱ)

Ocean Engineering (2023)

Bolong Liu Xiaojun Xu Dibo Pan

Flow resistance

10.1016/j.oceaneng.2023.115175

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Citations (7)

Drag reduction configuration analysis of the grooves on amphibious vehicles walking mechanism

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science (2022)

Bolong Liu Xiaojun Xu Dibo Pan

Amphibious vehicles are usually equipped with walking mechanisms and grooves which greatly affect the resistance characteristics of sailing. For purpose of improving the sailing speed and reduce energy consumption, the additional resistance at the groove is studied by numerical calculation. A Computational Fluid Dynamics method based on Reynolds-averaged Navier-Stokes solver was used to simulate the resistance performance of the amphibious vehicle, which was verified by towing test. Based on the ideal model without grooves, the size and trend of additional resistance on grooves were compared and studied. Combined with the analysis of flow field and sailing attitude, the cause of additional resistance is explained. Four different groove configurations were compared and analyzed, respectively. The results show that the curved surface type HSAV-3 has better water resistance performance at high speed, which depends on its better flow diversion and lifting effect.

Towing

Groove (engineering)

Supercavitation

10.1177/09544062211065380

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Citations (11)

Study and optimization of a deformable trimaran amphibious transport vehicle's resistance characteristic

Physics of Fluids (2024)

Bolong Liu Dibo Pan Xiaojun Xu

Amphibious transport vehicles have increasingly become an important tool for connecting water and land transportation, serving both water and land transport missions. However, due to the unique shape of amphibious vehicles, their sailing resistance is high, which severely restricts their widespread use. In this paper, a deformable trimaran amphibious transport vehicle with retractable side hulls is designed. Based on the Reynolds-averaged Navier–Stokes equation, a resistance prediction method for amphibious vehicles is established and verified through towing experiments. The resistance characteristic of the trimaran vehicle is studied and optimized. First, the effects of the side hull and its position on resistance performance are analyzed, and the sensitivity of position parameters is evaluated. Then, the bow plate angle on resistance is analyzed. Finally, a surrogate model of the side hull position parameters and the bow plate angle with resistance is established using the Kriging method. The Particle Swarm Optimization is used to search for the minimum resistance configuration Opt 2, which achieves a drag reduction effect of 19.84% at the design speed.

10.1063/5.0205312

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Citations (1)

Influence of towing position on hydrodynamic characteristics of an Amphibious Tractor

Ocean Engineering (2023)

Xiaojun Xu Bolong Liu Dibo Pan Haijun Xu

Towing

Tractor

Position (finance)

10.1016/j.oceaneng.2023.113932

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Citations (7)

Research on sealing characteristics of annular power cylinder based on twin-rotor piston engine

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science (2021)

Dibo Pan Haijun Xu Bolong Liu Congnan Yang

The sealing characteristics of an annular power cylinder based on the Twin-rotor piston engine are studied, which provides a theoretical foundation for the sealing design of a new high-power density piston engine. In this paper, the basis thermodynamic realization process of an annular power cylinder is presented. The Runge Kutta equation is used to establish the coupled leakage model of adjacent working chambers under annular piston seal. And the sealing performance of the annular power cylinder is analyzed in detail. Moreover, the influence of rotor speed and compression ratio on the sealing characteristics and leakage is studied. Finally, some tests are carried out to verify the sealing principle and simulation results, which verifies the theoretical basis of simulation analysis. Results show that there are double pressure peaks in the leakage chamber between two working chambers, which is beneficial to reduce the leakage rate. Besides, increasing the speed and decreasing the compression ratio can help to reduce gas leakage. Furthermore, the effects of speed variation on the leakage are only significant when rotating at low speed. Changing the compression ratio has a greater effect on the slope of the leakage curve at a low compression ratio, and the lower the compression ratio, the better the sealing effect.

Leakage (economics)

Piston (optics)

Position-sensing hydraulic cylinder

Overall pressure ratio

10.1177/09544062211021440

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Citations (6)