We first analyzed the force and motion of naval aircraft during launching process.Further,we investigated the ship deck with the form of a ramp and established deck motion model and ship airwake model.Finally,we condu...We first analyzed the force and motion of naval aircraft during launching process.Further,we investigated the ship deck with the form of a ramp and established deck motion model and ship airwake model.Finally,we conducted simulations at medium sea.Results showed that the effects of deck motion on takeoff varied with initial phases,and airwake could help reducing aircraft′s sinkage.We also found that the deck motion played a major role in the effects caused by the interaction of deck motion and ship airwake.展开更多
A numerical method is proposed for predicting six degree of freedom ship motion with green water on deck.Numerical results are presented which show the dynamic effect of water on deck on the ship motion.
This paper presents the results of an experimental investigation dealing with the effect of bow overhang extensions on the quantity of shipping water over the foredeck in case of ships advancing in regular head waves....This paper presents the results of an experimental investigation dealing with the effect of bow overhang extensions on the quantity of shipping water over the foredeck in case of ships advancing in regular head waves. To perform this investigation, a series of free-running tests was conducted in regular waves using an experimental model of a multipurpose cargo ship to quantify the amount of shipping water. The tests were performed on five bow overhang variants with several combinations of wavelength and ship speed conditions. It was observed that the quantity of shipping water was affected by some parameters such as wavelength, ship speed, and bow shape in terms of an overhang extension. The results show the significant influence of an overhang extension, which is associated with the bow flare shape, on the occurrence of water shipping. These results involve the combined incoming regular waves and model speed.展开更多
Based on the Finite Element Analysis and Thin Walled-Box girder Mechanics, two design concepts of adding box girders under main deck in order to increase the hull strength of ship are presented. By comparison and anal...Based on the Finite Element Analysis and Thin Walled-Box girder Mechanics, two design concepts of adding box girders under main deck in order to increase the hull strength of ship are presented. By comparison and analysis on the longitudinal strength, torsion strength and deck buckling between designed concepts and the original concept, it is found that by adding box girders under the main deck, the weight of hull structure is increased by lower than 10%, but the stress on the plate of the main deck is reduced by about 10%, the stress on the plating of the second deck is reduced about 20%. The shear stress on the plating of both of the main deck and second deck is reduced, but the shear stresses in several nodes are increased. Also the capability of resisting damage to ship is obviously increased by adding box girders under the main deck. The deck buckling is also increased by more than 90%. Consequently, the box girders added under the main deck are useful and effective to increase the strength of hull and ship survivability.展开更多
针对直升机着舰过程中的下滑进场环节,从流场环境对直升机飞行品质影响的角度出发,研究了直升机着舰策略。分析了下滑进场区域的流场分布,研究表明流场的分布与距离甲板的高度相关,高度越低,气流速度均值越大,且下洗气流主要集中在迎甲...针对直升机着舰过程中的下滑进场环节,从流场环境对直升机飞行品质影响的角度出发,研究了直升机着舰策略。分析了下滑进场区域的流场分布,研究表明流场的分布与距离甲板的高度相关,高度越低,气流速度均值越大,且下洗气流主要集中在迎甲板风方向的路线区域,对直升机的飞行品质造成影响。分析了不同甲板风(Wind on deck,WOD)条件下直升机平衡状态量,分别从旋翼所需功率、操纵量和机体姿态等方面对进场方式进行了研究,表明合理的进场方式有利于着舰安全。展开更多
基金supported by the National Natural Science Foundation of China(No.61304223)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20123218120015)
文摘We first analyzed the force and motion of naval aircraft during launching process.Further,we investigated the ship deck with the form of a ramp and established deck motion model and ship airwake model.Finally,we conducted simulations at medium sea.Results showed that the effects of deck motion on takeoff varied with initial phases,and airwake could help reducing aircraft′s sinkage.We also found that the deck motion played a major role in the effects caused by the interaction of deck motion and ship airwake.
文摘A numerical method is proposed for predicting six degree of freedom ship motion with green water on deck.Numerical results are presented which show the dynamic effect of water on deck on the ship motion.
文摘This paper presents the results of an experimental investigation dealing with the effect of bow overhang extensions on the quantity of shipping water over the foredeck in case of ships advancing in regular head waves. To perform this investigation, a series of free-running tests was conducted in regular waves using an experimental model of a multipurpose cargo ship to quantify the amount of shipping water. The tests were performed on five bow overhang variants with several combinations of wavelength and ship speed conditions. It was observed that the quantity of shipping water was affected by some parameters such as wavelength, ship speed, and bow shape in terms of an overhang extension. The results show the significant influence of an overhang extension, which is associated with the bow flare shape, on the occurrence of water shipping. These results involve the combined incoming regular waves and model speed.
文摘Based on the Finite Element Analysis and Thin Walled-Box girder Mechanics, two design concepts of adding box girders under main deck in order to increase the hull strength of ship are presented. By comparison and analysis on the longitudinal strength, torsion strength and deck buckling between designed concepts and the original concept, it is found that by adding box girders under the main deck, the weight of hull structure is increased by lower than 10%, but the stress on the plate of the main deck is reduced by about 10%, the stress on the plating of the second deck is reduced about 20%. The shear stress on the plating of both of the main deck and second deck is reduced, but the shear stresses in several nodes are increased. Also the capability of resisting damage to ship is obviously increased by adding box girders under the main deck. The deck buckling is also increased by more than 90%. Consequently, the box girders added under the main deck are useful and effective to increase the strength of hull and ship survivability.
文摘针对直升机着舰过程中的下滑进场环节,从流场环境对直升机飞行品质影响的角度出发,研究了直升机着舰策略。分析了下滑进场区域的流场分布,研究表明流场的分布与距离甲板的高度相关,高度越低,气流速度均值越大,且下洗气流主要集中在迎甲板风方向的路线区域,对直升机的飞行品质造成影响。分析了不同甲板风(Wind on deck,WOD)条件下直升机平衡状态量,分别从旋翼所需功率、操纵量和机体姿态等方面对进场方式进行了研究,表明合理的进场方式有利于着舰安全。
