检索结果-南通市图书馆

Step-by-Step numerical prediction of Aerodynamic Noise Generated by High Speed Trains

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2022年第2期35卷 251-264页

作者： Tian Li Deng Qin Ning Zhou Weihua Zhang State Key Laboratory of Traction Power Southwest Jiaotong UniversityChengdu 610031China

In this paper,the unsteady flow around a high-speed train is numerically simulated by detached eddy simulation method(DES),and the far-field noise is predicted using the Ffowcs Williams-Hawkings(FW-H)acoustic model.The reliability of the numerical calculation is verified by wind tunnel experiments.The superposition relationship between the far-field radiated noise of the local aerodynamic noise sources of the high-speed train and the whole noise source is analyzed.Since the aerodynamic noise of high-speed trains is derived from its different components,a stepwise calculation method is proposed to predict the aerodynamic noise of high-speed trains.The results show that the local noise sources of high-speed trains and the whole noise source conform to the principle of sound source energy superposition.Using the head,middle and tail cars of the high-speed train as noise sources,different numerical models are established to obtain the far-field radiated noise of each aerodynamic noise source.The far-field total noise of high-speed trains is predicted using sound source superposition.A step-by-step calculation of each local aerodynamic noise source is used to obtain the superimposed value of the far-field noise.This is consistent with the far-field noise of the whole train model’s aerodynamic noise.The averaged sound pressure level of the far-field longitudinal noise measurement points differs by 1.92 dBA.The step-by-step numerical prediction method of aerodynamic noise of high-speed trains can provide a reference for the numerical prediction of aerodynamic noise generated by long marshalling high-speed trains.

关键词： High-speed train Aerodynamic noise Sound source superposition numerical prediction

numerical prediction of 3-D periodic flow unsteadiness in a centrifugal pump under part-load condition

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2014年第2期26卷 257-263页

作者：裴吉袁寿其李晓俊袁建平 National Research Center of Pumps Jiangsu University

numerical simulation and 3-D periodic flow unsteadiness analysis for a centrifugal pump with volute are carried out in whole flow passage, including the impeller with twisted blades, the volute and the side chamber channels under a part-load condition. The pressure fluctuation intensity coefficient （PFIC） based on the standard deviation method, the time-averaged velocity unsteadiness intensity coefficient （VUIC） and the time-averaged turbulence intensity coefficient （TIC） are defined by averaging the results at each grid node for an entire impeller revolution period. Therefore, the strength distributions of the periodic flow unsteadiness based on the unsteady Reynolds-averaged Navier-Stokes （URANS） equations can be analyzed directly and in detail. It is shown that under the 0.6Qd~. condition, the pressure fluctuation intensity is larger near the blade pressure side than near the suction side, and a high fluctuation intensity can be observed at the beginning section of the spiral of the volute. The flow velocity unsteadiness intensity is larger near the blade suction side than near the pressure side. A strong turbulence intensity can be found near the blade suction side, the impeller shroud side as well as in the side chamber. The leakage flow has a significant effect on the inflow of the impeller, and can increase both the flow velocity unsteadiness intensity and the turbulence intensity near the wall. The accumulative flow unstea- diness results of an impeller revolution can be an important aspect to be considered in the centrifugal pump optimum design for obtaining a more stable inner flow of the pump and reducing the flow-induced vibration and noise in certain components.

关键词： numerical prediction flow unsteadiness turbulence intensity centrifugal pump with volute

numerical prediction of the incremental melting and solidification process

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2003年第4期10卷 50-54页

作者： Jun Wang, Chengchang Jia, and Sheng YinMaterials Science and Engineering School, University of Science and Technology Beijing, Beijing 100083, China Mat. Sci. and Eng. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

A mathematical formulation is applied to represent the phenomena in theincremental melting and solidification process (IMSP), and the temperature and electromagneticfields and the depth of steel liquid phase are calculated by a finite difference technique using thecontrol volume method. The result shows that the predicted values are in good agreement with theobservations. In accordance with the calculated values for different kinds of materials anddifferent size of molds, the technological parameter of the IMS process such as the power supply andthe descending speed rate can be determined.

关键词： incremental melting and solidification process (IMSP) numerical prediction electromagnetic field temperature field technological parameter

numerical prediction OF VORTEX FLOWIN HYDRAULIC TURBINE DRAFT TUBE FOR LES

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2005年第4期17卷 448-454页

作者： LIU Xiao-bing ZENG Yong-zhong CAO Shu-you School of Energy and Environment Xihua University Chengdu 610039 China State Key Hydraulics Laboratory of High Speed Flows Sichuan University Chengdu 610065 China

The three-dimensional unsteady turbulent flow is studied numerically in the whole flow passage of hydraulic turbine, and vortex flow in the draft tube is predicted accurately in this paper. The numerical prediction is based on the Navier-Stokes equations and Large-Eddy Simulation （LES） model. The SIMPLE algorithm with the body fitted coordinate and tetrahedroid grid system is applied for the solution of the discretization governing equations.

关键词： vortex flow hydraulic turbine draft tube numerical prediction LES

numerical prediction of hydrodynamic forces on a ship passing through a lock with different configurations

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2014年第1期26卷 1-9页

作者：王宏志邹早建 School of Naval Architecture Ocean and Civil Engineering and State Key Laboratory of Ocean EngineeringShanghai Jiao Tong University

A CFD method is used to numerically predict the hydrodynamic forces and moments acting on a ship passing through a lock with a constant speed. By solving the RANS equations in combination with the RNG k-e turbulence model, the unsteady viscous flow around the ship is simulated and the hydrodynamic forces and moments acting on the ship are calculated. UDF is com-piled to define the ship motion. Meanwhile, grid regeneration is dealt with by using the dynamic mesh method and sliding interface technique. Under the assumption of low ship speed, the effects of free surface elevation are neglected in the numerical simulation. A bulk carrier ship model is taken as an example for the numerical study. The numerical results are presented and compared with the available experimental results. By analyzing the numerical results obtained for locks with different configurations, the influences of approach wall configuration, lock configuration symmetry and lock chamber breadth on the hydrodynamic forces and moments are demonstrated. The numerical method applied in this paper can qualitatively predict the ship-lock hydrodynamic interaction and pro-vide certain guidance on lock design.

关键词： ship-lock hydrodynamic interaction numerical prediction lock configuration lock design

numerical prediction OF PROCESS-INDUCED RESIDUAL STRESSES IN GLASS BULB PANEL

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2006年第9期27卷 1197-1206页

作者：周华民孙强奚国栋李德群 State Key Lab of Plastic Forming Simulation and Mold and Die Technology Huazhong University of Science and Technology Wuhan 430074 P. R. China

A numerical simulation model for predicting residual stresses which arise during the solidification process of pressed glass bulb panel was developed. The solidification of a molten layer of glass between cooled parallel plates was used to model the mechanics of the buildup of residual stresses in the forming process. A thermorheologically simple thermoviscoelastic model was assumed for the material. The finite element method employed was based on the theory of shells as an assembly of flat elements. This approach calculates residual stresses layer by layer like a truly three-dimensional calculation, which is well suited for thin pressed products of complex shape. An experimental comparison was employed to verify the proposed models and methods.

关键词： glass bulb pressing residual stresses numerical prediction

numerical prediction experiment on Typhoon Maggie (9903)

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2001年第2期20卷 171-182页

作者： Fong Soi Kun, Wu Chisheng, Hao I Pan, Lam Kin Hang Ku Chi Meng, Wang Anyu, Lin Wenshi (1. Macao Meteorological and Geophysical Bureau, Macao, China 2. Department of Atmospheric Sciences, Zhongshan University, Guangzhou 510275, China) Macao Meteorological/Geophysical Bur Department of Atmospheric Sciences Zhongshan University Macao Macau

The movement of Typhoon Maggie (9903) in June 1999 is one of the rare cases ever seen in the history. At 00U on June 6 Maggie was located at about 70 km to the southwest of Taiwan. When it arrived at the coastal region of Shanwei City (22.8N, 116.5E), it turned suddenly to move southwestward along the southern China coastal line. De June 7 Maggie finally turned to move northward, making landfall to the north of Shangchuan Island. The experimental numerical prediction system on typhoon movement that was designed based on MM5 is proved quite successful for the 48h prediction of Maggie's movement and rainfall. The mean prediction error of typhoon track is 81 km for 0-24 h and 74 km for 24-48 h. The location of typhoon center in the initial field of the model is approximately 100 km away from the actual observations. In order to modify the location of typhoon center, a bogus typhoon was intro- duced into the model and the prediction of typhoon track was improved in 0-24 h time interval. But the prediction error was enlarged in 24-36 h. We also performed a sensitivity experiment of changing the land of southern China into the ocean. It is found that the orientation of South China coastal line and the topography have no obvious effect on the movement of Typhoon Maggie.

关键词： Typhoon movement numerical prediction South China coastal line

Experimental and numerical prediction of railway induced vibration

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2012年第11期13卷 802-813页

作者： Hans VERBRAKEN Geert LOMBAERT Geert DEGRANDE Department of Civil Engineering KU LeuvenKasteelpark Arenberg 40 B24483001 HeverleeBelgium

In this paper,both measurements and numerical simulations of railway induced vibration are discussed.A measurement campaign has been carried out along the high-speed railway track in Lincent,Belgium.The experimental determination of transfer functions and vibration velocity during train passages are discussed.A numerical model is introduced to predict the transfer functions and the vibration velocity during train passages.The comparison of experimental and numerical results demonstrates the importance of accurate numerical models and input data.The results are obtained in the framework of the development of a hybrid prediction method,where numerical and experimental data can be combined to improve the prediction accuracy for railway induced vibration.

关键词： Component Railway induced vibration Experimental prediction numerical prediction

numerical prediction OF SURFACE DEFORMATION ＆ RESIDUAL STRESS OF 2024-T3 ALUNINUM ALLOY SHOCKED BY INTENSE LASER

在线全文

学校读者我要写书评

暂无评论

NUMERICAL PREDICTION OF SURFACE DEFORMATION ＆ RESIDUAL STRE...