Combination with the hydrodynamic characteristics of the asymmetric catamaran, the effects of asymmetric terms on the hydrodynamic derivatives of the oblique towing motion, turning motion, and the higher-order coupled hydrodynamic derivatives are studied by CFD technology based on the viscous fluid theory. Based on the MMG model, the turning and zig-zag maneuvers and related maneuvering motion parameters of the asymmetric catamaran are predicted and their characteristics are analyzed. According to the results of numerical simulation, the maneuvering motion under positive rudder Angle and negative rudder Angle is compared, and it is obtained that the side body of the asymmetric catamaran has obvious influence on the rotary motion and z-shape motion, and the maneuverability prediction of the asymmetric catamaran is realized.
In recent years, high-performance ships have developed rapidly, especially catamarans and trimarans. Asymmetric catamaran is a new type of high-performance ship in the early 21st century. Compared with the traditional symmetric catamaran, the so-called asymmetric ship type refers to the ship type in which the cross section of the hull forms an asymmetric shape below the design waterline. In addition to the advantages of catamaran and trimaran in stability and large deck area, this ship type also has the advantages of excellent seaworthiness and easy parallel docking.
However, at present, although asymmetric catamaran yachts have been built, for example, the world's first asymmetric catamaran yacht named "Asian lady" made by Yantai Raffles shipyard in 2003, there are few theoretical studies on such ship types. At present, there is a lack of research on the hydrodynamic performance of asymmetric catamaran at home and abroad. In the last decade, the research on this kind of ship type has mostly focused on stability, resistance and motion performance. Jia et al of Dalian University of technology theoretically deduced the initial stability formula of asymmetric catamaran and deduced the formula for calculating the initial stability height GM of asymmetric catamaran (Jia et al., 2007).Huang et al. analyzed the vibration performance of asymmetric catamaran, and studied the vibration performance of asymmetric catamaran by analyzing and comparing with the results of conventional catamaran by using the method of three-dimensional finite element and empirical formula (Huang et al., 2007). Liu Jia used LS Duna display nonlinear dynamic analysis software to numerically simulate the attack of an asymmetric catamaran in regular waves, studied the characteristics of water attack, and came to the conclusion that the main body is more prone to attack than the side body when the ship has no initial roll, and the attack pressure will be greater in the corresponding attack area (Liu Jia et al., 2010). Li et al. applied the time domain panel method to solve the wave making problem of asymmetric catamaran based on Green's theorem (Li et al., 2013). Li et al. continued to discuss the calculation method of wave making resistance of asymmetric catamaran. They discussed the calculation method of wave making resistance of asymmetric catamaran according to the linear wave making theory, optimized the wave making resistance based on the optimization platform, studied the interference law of side body layout on ship wave making resistance, and selected the ship type layout with the lowest wave making resistance (Li et al., 2013). The influence of Dowson's free surface conditions on the navigation of the ship in 2019 is discussed (Gong et al., 2019). Jiang Fan et al. (2021) Based on the open source CFD solver open foam, numerically simulated the fixed length rotary motion of the model under different rudder angles and the Z-shaped motion under high rudder angles, and realized the prediction of the maneuverability of this kind of catamaran.
