Based on the matching conditions of different fluid regions, the eigenfunction expansion method is used to develop a theoretical formula for wave reflection in front of the perforated structure with a partially slit f...Based on the matching conditions of different fluid regions, the eigenfunction expansion method is used to develop a theoretical formula for wave reflection in front of the perforated structure with a partially slit front wall. The accuracy of the solution is verified by comparing the numerical results with experimental data. In addition, a new hydraulic design method is developed by derivation of the theoretical formula with respect to the porosity of the slit wall, and the results of this design method is drafted for harbour engineers to use.展开更多
In the design of a hypersonic inward-turning inlet by applying the traditional basic flowfield, a reflected shock-wave is formed in the isolator due to the continuous reflection of the cowlreflected shock wave in the ...In the design of a hypersonic inward-turning inlet by applying the traditional basic flowfield, a reflected shock-wave is formed in the isolator due to the continuous reflection of the cowlreflected shock wave in the basic flow-field, which interacts with the boundary layer to produce a considerable influence on the performance of the inlet. Here, a basic flow-field design method that can control the velocity direction at the throat section is developed, and numerical simulations are conducted to demonstrate the effectiveness of this method. The method presented in this paper can achieve the absorption of the reflected waves at the shoulder of the basic flow-field by adjusting the variation law of the center radius in the basic flow-field, and a smooth transition between the compression surface and the isolator can also be produced. The Mach number and total pressure recovery coefficient of the inlet designed according to this method are 3.00 and 0.657, respectively, at design point(the incoming flow Mach number Ma1= 6.0). The results show that with this method, the inlet can efficiently weaken both the reflection of the shock wave and the interaction between the boundary layer and the reflected shock waves, which improves the aerodynamic performance of the inlet.展开更多
As a new type of marine structure,floating breakwater can provide suitable water area for coastal residents.In this paper,a multi-module floating breakwater with three cylinders was designed.According to the character...As a new type of marine structure,floating breakwater can provide suitable water area for coastal residents.In this paper,a multi-module floating breakwater with three cylinders was designed.According to the characteristics of each module,the elastic connector was created.The cabins with functions such as living,generating electricity and entertainment were arranged.A linear spring constrained design wave(LSCDW)method for strength analysis of floating marine structures with multi-module elastic connections was proposed.The numerical model was verified by 1:50 similarity ratio in the test tank.According to the analysis of design wave and extreme wave conditions,considering the mooring loads and environmental loads and connector loads,the overall strength of breakwater was analyzed by LSCDW method.These studies can provide new insights and theoretical guidance for the design of multi-module floating structures.展开更多
In this paper,using potential flow theory and assuming that the pressure in the air cabin is proportional to the vertical velocity of the water column,we establish a hydrodynamic model for OWC wave energy convertors,r...In this paper,using potential flow theory and assuming that the pressure in the air cabin is proportional to the vertical velocity of the water column,we establish a hydrodynamic model for OWC wave energy convertors,resulting in a collection of illustrative plates,from which the behaviour of an OWC and the relation between its parameters are discussed. Optimization theory is used to design an optimum convertor working in irregular waves. It is found that the numerical results fit well the experimental data.展开更多
依据ABS(American Bureau of Shipping)和DNV(Det Norske Veritas)规范,对适用于深水半潜式平台波浪载荷计算的确定性和随机性设计波法进行了研究.以两艘不同形式的半潜式平台作为实际算例,对比分析了按照不同规范给出的确定性设计波法...依据ABS(American Bureau of Shipping)和DNV(Det Norske Veritas)规范,对适用于深水半潜式平台波浪载荷计算的确定性和随机性设计波法进行了研究.以两艘不同形式的半潜式平台作为实际算例,对比分析了按照不同规范给出的确定性设计波法计算结果的差异,并将确定性设计波法与随机性设计波法的计算结果进行了对比,所得结论可为该类平台的总体结构强度评估与结构设计提供参考.展开更多
文摘Based on the matching conditions of different fluid regions, the eigenfunction expansion method is used to develop a theoretical formula for wave reflection in front of the perforated structure with a partially slit front wall. The accuracy of the solution is verified by comparing the numerical results with experimental data. In addition, a new hydraulic design method is developed by derivation of the theoretical formula with respect to the porosity of the slit wall, and the results of this design method is drafted for harbour engineers to use.
基金supported by the National Natural Science Foundation of China (Nos. 11702229, 11602207 and 91641103)
文摘In the design of a hypersonic inward-turning inlet by applying the traditional basic flowfield, a reflected shock-wave is formed in the isolator due to the continuous reflection of the cowlreflected shock wave in the basic flow-field, which interacts with the boundary layer to produce a considerable influence on the performance of the inlet. Here, a basic flow-field design method that can control the velocity direction at the throat section is developed, and numerical simulations are conducted to demonstrate the effectiveness of this method. The method presented in this paper can achieve the absorption of the reflected waves at the shoulder of the basic flow-field by adjusting the variation law of the center radius in the basic flow-field, and a smooth transition between the compression surface and the isolator can also be produced. The Mach number and total pressure recovery coefficient of the inlet designed according to this method are 3.00 and 0.657, respectively, at design point(the incoming flow Mach number Ma1= 6.0). The results show that with this method, the inlet can efficiently weaken both the reflection of the shock wave and the interaction between the boundary layer and the reflected shock waves, which improves the aerodynamic performance of the inlet.
基金the National Natural Science Foundation of China(No.52071161)。
文摘As a new type of marine structure,floating breakwater can provide suitable water area for coastal residents.In this paper,a multi-module floating breakwater with three cylinders was designed.According to the characteristics of each module,the elastic connector was created.The cabins with functions such as living,generating electricity and entertainment were arranged.A linear spring constrained design wave(LSCDW)method for strength analysis of floating marine structures with multi-module elastic connections was proposed.The numerical model was verified by 1:50 similarity ratio in the test tank.According to the analysis of design wave and extreme wave conditions,considering the mooring loads and environmental loads and connector loads,the overall strength of breakwater was analyzed by LSCDW method.These studies can provide new insights and theoretical guidance for the design of multi-module floating structures.
文摘In this paper,using potential flow theory and assuming that the pressure in the air cabin is proportional to the vertical velocity of the water column,we establish a hydrodynamic model for OWC wave energy convertors,resulting in a collection of illustrative plates,from which the behaviour of an OWC and the relation between its parameters are discussed. Optimization theory is used to design an optimum convertor working in irregular waves. It is found that the numerical results fit well the experimental data.
文摘依据ABS(American Bureau of Shipping)和DNV(Det Norske Veritas)规范,对适用于深水半潜式平台波浪载荷计算的确定性和随机性设计波法进行了研究.以两艘不同形式的半潜式平台作为实际算例,对比分析了按照不同规范给出的确定性设计波法计算结果的差异,并将确定性设计波法与随机性设计波法的计算结果进行了对比,所得结论可为该类平台的总体结构强度评估与结构设计提供参考.
