Three-dimensional modeling of virtual hoisting machinery is the critical works to structure the system of virtual construction, and the foundation to realize intelligent and interactive virtual hoisting. Aimed at enha...Three-dimensional modeling of virtual hoisting machinery is the critical works to structure the system of virtual construction, and the foundation to realize intelligent and interactive virtual hoisting. Aimed at enhancing the requests of image quality and stability of the virtual construction scene, taking a tower crane for example. We studied the technology of three-dimensional modeling and optimization of a virtual tower crane, and a method named two-stage model optimization was put forward. This depended on the modeling stage using Solidworks and 3DS Max and the performance optimization stage in EON. The practice of software development indicates that the proposed methods of three-dimensional modeling and optimization could satisfy the performance request of virtual construction system and be popularized to other virtual system.展开更多
In this paper, some experimental studies on the impact of effluent from an exhaust tower of an underground tunnel with special construction are reported. By measuring the flow field downstream of the tower in NJU mete...In this paper, some experimental studies on the impact of effluent from an exhaust tower of an underground tunnel with special construction are reported. By measuring the flow field downstream of the tower in NJU meteorological wind tunnel, some flow characteristics in the make area were established. Based on these, an advanced random\|walk dispersion model was set up and applied successfully to the simulation of dispersion in the wake area. The modelling results were in accordance with wind tunnel measurements. The computed maximum of ground surface concentration in the building case was a factor of 3-4 higher than that in the flat case and appeared much closer to the source. The simulation indicated that random walk modelling is an effective and practical tool for the wake stream impact assessment.展开更多
This article reports the findings on the adverse effect of the crosswind on the performance of natural draft cooling towers through numerical computation with the k-epsilon eddy-viscosity turbulence model. It is obser...This article reports the findings on the adverse effect of the crosswind on the performance of natural draft cooling towers through numerical computation with the k-epsilon eddy-viscosity turbulence model. It is observed here that the cause of the adverse effect of the crosswind on the cooling towers call be attributed to the around flow effect which destroys the radial inflow into the cooling towers when the wind is absent. Hence, a significant deterioration in the heat transfer from the heat exchangers at lateral sides occurs.展开更多
Jiangyin Yangtze highway bridge is a suspension bridge with main span 1 385 m. The south tower pier is located on a 70 m bedrock slope with bedding plane of strata tipping to the river channel and several weak interca...Jiangyin Yangtze highway bridge is a suspension bridge with main span 1 385 m. The south tower pier is located on a 70 m bedrock slope with bedding plane of strata tipping to the river channel and several weak intercalated layers. The stability of the tower pier is one of the main engineering geologic problems. On the basis of investigation and survey of relevant geologic condition analyses, the geomechanical model experiments are carried out for stability study of various foundation alternatives’ advantages and disadvantages. Pile foundation has been finally adopted and constructed, and this is justified by practice.展开更多
钢管塔力学性能卓越,在电网中应用广泛。其中钢管塔主要钢管构件长细比较大,低风速下易涡激振动,进而引起结构疲劳损伤,引起连接处损坏,严重影响结构的安全性与耐久性。针对目前钢管塔杆件涡振理论研究不充分现状,基于Van Der Pol式尾...钢管塔力学性能卓越,在电网中应用广泛。其中钢管塔主要钢管构件长细比较大,低风速下易涡激振动,进而引起结构疲劳损伤,引起连接处损坏,严重影响结构的安全性与耐久性。针对目前钢管塔杆件涡振理论研究不充分现状,基于Van Der Pol式尾流振子模型进行结构计算,采用中心差分法解模型耦合方程,编制圆钢管涡激振动计算程序并设计风洞试验验证其准确性,旨在研究圆钢管的涡激振动特性,为钢管塔涡振预测及控制提供理论依据。试验与数值计算结果的比较表明,该文建立的尾流振子模型能够较好地拟合钢管的位移,由于理论模型采用理想铰接约束,试验测得的涡振锁定区较短,且锁定频率低于理论值。展开更多
基金supported by Special Project of Scientific Research of Education Department of Shaanxi Provincial Government under Grant No.11JK0967
文摘Three-dimensional modeling of virtual hoisting machinery is the critical works to structure the system of virtual construction, and the foundation to realize intelligent and interactive virtual hoisting. Aimed at enhancing the requests of image quality and stability of the virtual construction scene, taking a tower crane for example. We studied the technology of three-dimensional modeling and optimization of a virtual tower crane, and a method named two-stage model optimization was put forward. This depended on the modeling stage using Solidworks and 3DS Max and the performance optimization stage in EON. The practice of software development indicates that the proposed methods of three-dimensional modeling and optimization could satisfy the performance request of virtual construction system and be popularized to other virtual system.
文摘In this paper, some experimental studies on the impact of effluent from an exhaust tower of an underground tunnel with special construction are reported. By measuring the flow field downstream of the tower in NJU meteorological wind tunnel, some flow characteristics in the make area were established. Based on these, an advanced random\|walk dispersion model was set up and applied successfully to the simulation of dispersion in the wake area. The modelling results were in accordance with wind tunnel measurements. The computed maximum of ground surface concentration in the building case was a factor of 3-4 higher than that in the flat case and appeared much closer to the source. The simulation indicated that random walk modelling is an effective and practical tool for the wake stream impact assessment.
基金The project supported by the National Natural Science Foundation of China (19725208) and the National Climbing project of China
文摘This article reports the findings on the adverse effect of the crosswind on the performance of natural draft cooling towers through numerical computation with the k-epsilon eddy-viscosity turbulence model. It is observed here that the cause of the adverse effect of the crosswind on the cooling towers call be attributed to the around flow effect which destroys the radial inflow into the cooling towers when the wind is absent. Hence, a significant deterioration in the heat transfer from the heat exchangers at lateral sides occurs.
文摘Jiangyin Yangtze highway bridge is a suspension bridge with main span 1 385 m. The south tower pier is located on a 70 m bedrock slope with bedding plane of strata tipping to the river channel and several weak intercalated layers. The stability of the tower pier is one of the main engineering geologic problems. On the basis of investigation and survey of relevant geologic condition analyses, the geomechanical model experiments are carried out for stability study of various foundation alternatives’ advantages and disadvantages. Pile foundation has been finally adopted and constructed, and this is justified by practice.
文摘钢管塔力学性能卓越,在电网中应用广泛。其中钢管塔主要钢管构件长细比较大,低风速下易涡激振动,进而引起结构疲劳损伤,引起连接处损坏,严重影响结构的安全性与耐久性。针对目前钢管塔杆件涡振理论研究不充分现状,基于Van Der Pol式尾流振子模型进行结构计算,采用中心差分法解模型耦合方程,编制圆钢管涡激振动计算程序并设计风洞试验验证其准确性,旨在研究圆钢管的涡激振动特性,为钢管塔涡振预测及控制提供理论依据。试验与数值计算结果的比较表明,该文建立的尾流振子模型能够较好地拟合钢管的位移,由于理论模型采用理想铰接约束,试验测得的涡振锁定区较短,且锁定频率低于理论值。
