超标洪水水位流量关系线拟定方法

为有效应对洪水灾害领域"黑天鹅"和"灰犀牛"事件,确保水文测站发生超标洪水时测得到报得出,有力支撑防洪减灾,对承担报汛任务的国家基本水文站需编制超标洪水测报预案。文章在呼和浩特市辖区国家基本水文站现状测报能力和防洪需求的基础上,对水文测站超标洪水水位流量关系线的拟定方法进行了浅析,提出了存在问题和建议。

螺旋桨轴承力计算方法的对比分析

为了对螺旋桨的轴承力进行研究,在标模SUBOFF尾部同一位置装上4种不同的螺旋桨,分别用CFD方法、拟定常方法以及升力线理论进行螺旋桨轴承力理论预报。根据计算结果,分析侧斜、叶数对螺旋桨轴承力的影响以及不同方向轴承力的相对大小,并对3种方法的优缺点进行总结。结果表明:CFD与升力线理论方法更适合工程需要,尤其是对侧斜较大的桨叶,其较拟定常方法有着比较好的预报效果;同时,升力线理论方法在计算效率方面优于CFD方法;并且螺旋桨轴承力随着叶数的增多、侧斜度的增大而减小;轴承力在y方向上力的分量均大于x方向。

螺旋桨轴承力预报方法分析

用理论和经验方法对常规和非常规桨的轴承力进行计算 ,比较分析后讨论了经验方法的适用范围。

浅谈泸定水电站建设征地农村移民生产安置规划目标和安置标准拟定分析

水电工程建设征地农村移民安置规划目标和安置标准是水电工程建设征地农村移民安置规划的控制依据,也是检验移民安置成功与否的主要指标。农村移民安置规划目标和安置标准包括生产安置和搬迁安置,其中生产安置包括开发土地、内部调地等有土安置和养老保障、投亲靠友、自谋出路、自谋职业等非农业安置方式;搬迁安置包括集中建房安置和自主择址建房安置等。在农村移民安置规划中,移民安置规划目标和安置标准拟定的正确与否,直接关系到移民个人切身利益及其合法权益,对移民安置后能否达到或超过其原有生产生活水平影响较大,尤其关系到少数民族地区的社会和谐与稳定。结合泸定水电站移民安置规划工程实例,主要探讨了农村移民生产安置规划目标和安置标准拟定方法。

汽车针刺地毯摩擦起球试验方法拟定及影响因素分析

汽车地毯在经过数十次踩踏摩擦后起球事件频发,外观质感下降。本文通过试验对比,拟定了耐摩擦起球试验方法,并对针刺地毯摩擦起球影响因素进行分析,希望提升耐摩擦起球的品质,给用户提供更佳体验。

浅析山区高速公路路线设计

以湖北宜都至来凤高速公路鹤峰(容美)至宣恩(当阳坪)段路线方案设计为例,浅析山区高速公路路线设计的设计理念。路线方案布设的原则及路线方案拟定的方法,为类似山区高速公路的路线设计提供重要的参考。

运用CAD技术进行非标设备模块化设计

从目前情况看增加产品多样性及其个性化成为占领市场满足客户需求的重要手段。产品需求的变化也促进了生产方式的转变，非标设计研究和解决了快速进行新产品的创新设计以满足市场并在最短的时闻内以低成本将新产品投放市场，本文阐述了非标设计的设计方法及制作特点。比较传统设计和积木式设计的优略，研究了非标零件标准件库的建设，分析了具体产品方案的拟定方法。

A purely data driven method for European option valuation

An alternative option pricing method is proposed based on a random walk market model. The minimal entropy martingale measure which adopts no arbitrage opportunity in the market, is deduced for this market model and is used as the pricing measure to evaluate European call options by a Monte Carlo simulation method. The proposed method is a purely data driven valuation method without any distributional assumption about the price process of underlying asset. The performance of the proposed method is compared with the canonical valuation method and the historical volatility-based Black-Scholes method in an artificial Black-Scholes world. The simulation results show that the proposed method has merits, and is valuable to financial engineering.

Interaction between anti-shear galleries and surrounding rock in the right-bank slope of Dagangshan hydropower station

The fight-bank slope of the Dagangshan hydropower station located in Southwest China is a highly unloaded rock slope. Moreover, large-scale natural faults were detected in the slope body; some excavation-induced unloading fractures were discovered at elevations between lo75m and 1146m. Because of poor tectonic stability, the excavation work was suspended in September 2009, and six large- scale anti-shear galleries were employed to replace the weak zone in the slope body to reinforce the fight- bank slope. In this study, based on microseismic- monitoring technology and a numerical-simulation method, the stabilities of the slope with and without the reinforcement are analysed. An in-situ microseismic-monitofing system is used to obtain quantitative information about the damage location, extent, energy, and magnitude of the rocks. Thus, any potential sliding block in the fight-bank slope can be identified. By incorporating the numerical results along with the microseismic-monitoring data, the stress concentration is found to largely occur aroundthe anti-shear galleries, and the seismic deformation near the anti-shear galleries is apparent, particularly at elevations of 121o, 118o, 115o, and 112om. To understand the interaction mechanism between the anti-shear gallery and the surrounding rock, a 2D simulation of the potential damage process occurring in an anti-shear gallery is performed. The numerical simulation helps in obtaining additional information about the stress distribution and failure-induced stress re-distribution in the vicinity of the anti-shear galleries that cannot be directly observed in the field. Finally, the potential sliding surface of the right-bank slope is numerically obtained, which generally agrees with the spatial distribution of the in-situ monitored microseismic events. The safety factor of the slope reinforced with the anti-shear gallery increases by approximately 36.2%. Both the numerical results and microseismic data show that the anti-shear galleries have a good reinforcement effect.

Simulation of Kelvin-Helmholtz Instability with Flux-Corrected Transport Method

The sixth-order accurate phase error flux-corrected transport numerical algorithm is introduced, and used to simulate Kelvin-Helmholtz instability. Linear growth rates of the simulation agree with the linear theories of Kelvin Helmholtz instability. It indicates the validity and accuracy of this simulation method. The method also has good capturing ability of the instability interface deformation.

Study on Unsteady Hydrodynamic Performance of Propeller in Waves

The speed of a ship sailing in waves always slows down due to the decrease in efficiency of the propeller. So it is necessary and essential to analyze the unsteady hydrodynamic performance of propeller in waves. This paper is based on the numerical simulation and experimental research of hydrodynamics performance when the propeller is under wave conditions. Open-water propeller performance in calm water is calculated by commercial codes and the results are compared to experimental values to evaluate the accuracy of the numerical simulation method. The first-order Volume of Fluid(VOF) wave method in STAR CCM+ is utilized to simulate the three-dimensional numerical wave. According to the above prerequisite, the numerical calculation of hydrodynamic performance of the propeller under wave conditions is conducted, and the results reveal that both thrust and torque of the propeller under wave conditions reveal intense unsteady behavior. With the periodic variation of waves, ventilation, and even an effluent phenomenon appears on the propeller. Calculation results indicate, when ventilation or effluent appears, the numerical calculation model can capture the dynamic characteristics of the propeller accurately, thus providing a significant theory foundation forfurther studying the hydrodynamic performance of a propeller in waves.

Building Vulnerability Evaluation in Landslide Deformation Phase

Building vulnerability evaluation is important in the risk assessment on earthquake and flood hazards. But for landslide hazard, it is also a very important part for the people in buildings. Most discussions or researches about building vulnerability are for landslide failure, few for landslide in deformation phase. For this objective, this paper discussed about building vulnerability evaluation using Zhaoshuling landslide as an example Zhaoshuling landslide named located in the Three Gorges Reservoir Area, China. After a field survey on the geological condition of landslide, detailed field investigation on the buildings' location and structure is carried out. To get landslide surface deformation, numerical simulation method is used under the combining condition of water fluctuation and rainfall. Then building deformation and probable damage degree is analyzed according to landslide surface deformation and the relative theory in mining. Based on the national standard building damage classification system, the vulnerability of all the buildings on the landslide is semi-quantitatively evaluated.

A Defined Process to Digitally Reproduce in 3D a Wide Set of Archaeological Artifacts for Virtual Investigation and Display

This paper contributes to depict the current pattern of applications of digital 3D models for professional research and practice, and for broader dissemination of cultural heritage. Passing from a general review to the illustration of the background project, named MUSINT, the authors underline the objectives. The present case study primarily aims to share information about valuable archaeological collections which have little visibility. To enhance the project＇s contents, which include a whole set of different artifacts, the authors have reproduced high resolution, faithful and measurable digital models on one side, and on the other, lower resolution and geometrically simplified models are yet completed and very close to reality. The former are meant to implement a scholars＇ archive for further scientific activity. The latter to provide content for virtual exhibitions on the Web or on stand-alone interfaces situated in the actual physical museum spaces. The data acquisition and post-processing methods which have been tested and chosen are here briefly described. Hence, the authors then give an account of the most recurrent problematic issues of the established work-flow and how they should be solved. Touched instances are the delicate placing of the artifacts, which must be digitized, in relation to the triangulation-based laser scanner＇s functionality, the refining operations in order to build a coherent single polygon mesh, the most effective ways to deal with unavoidable missing parts or defected textures in the generated model and so on.

Model identification of hydraulic flight simulator based on improved particle swarm optimization and wavelet analysis

A new model identification method of hydraulic flight simulator adopting improved panicle swarm optimization （PSO） and wavelet analysis is proposed for achieving higher identification precision. Input-output data of hydraulic flight simulator were decomposed by wavelet muhiresolution to get the information of different frequency bands. The reconstructed input-output data were used to build the model of hydraulic flight simulator with improved particle swarm optimization with mutation （IPSOM） to avoid the premature convergence of traditional optimization techniques effectively. Simulation results show that the proposed method is more precise than traditional system identification methods in operating frequency bands because of the consideration of design index of control system for identification.

Deformation tests and failure process analysis of an anchorage structure

In order to study the failure process of an anchorage structure and the evolution law of the body＇s defor- mation field, anchor push-out tests were carried out based on digital speckle correlation methods （DSCM）. The stress distribution of the anchorage interface was investigated using the particle flow numerical simulation method. The results indicate that there are three stages in the deformation and fail- ure process of an anchorage structure： elastic bonding stage, a de-bonding stage and a failure stage. The stress distribution in the interface controls the stability of the structure. In the elastic bonding stage, the shear stress peak point of the interface is close to the loading end, and the displacement field gradually develops into a ＂V＂ shape, in the de-bonding stage, there is a shear stress plateau in the center of the anchorage section, and shear strain localization begins to form in the deformation field. In the failure stage, the bonding of the interface fails rapidly and the shear stress peak point moves to the anchorage free end. The anchorage structure moves integrally along the macro-cracl~ The de-bonding stage is a research focus in the deformation and failure process of an anchorage structure, and plays an important guiding role in roadway support design and prediction of the stability of the surrounding rock.

Identification of ancient ceramics by digital shape characterization

Shapes are important clues for the identification of ancient ceramics.In this study,digital extraction methods of shape characterization were discussed,using samples of flared mouthed porcelain bowls produced in Jingdezhen Hutian Kiln from the Five Dynasties to the Song and Yuan period.By employing the techniques of image enhancement,edge detection and curve fitting of Matlab,the method using digital shape characterization has advanced accuracy and effectiveness of traditional identification which is based on visual and tactual inspections.Together with the increasingly applied compositional data analysis and thermoluminescence dating technique,the method will further improve and upgrade the scientific identification system for ancient ceramics.

A Novel Approach to Predict the Stability Limits of Combustion Chambers with Large Eddy Simulation

Lean premixed combustion,which allows for reducing the production of thermal NOx,is prone to combustion instabilities.There is an extensive research to develop a reduced physical model,which allows-without time-consuming measurements-to calculate the resonance characteristics of a combustion system consisting of Helmholtz resonator type components (burner plenum,combustion chamber).For the formulation of this model numerical investigations by means of compressible Large Eddy Simulation (LES) were carried out.In these investigations the flow in the combustion chamber is isotherm,non-reacting and excited with a sinusoidal mass flow rate.Firstly a combustion chamber as a single resonator subsequently a coupled system of a burner plenum and a combustion chamber were investigated.In this paper the results of additional investigations of the single resonator are presented.The flow in the combustion chamber was investigated without excitation at the inlet.It was detected,that the mass flow rate at the outlet cross section is pulsating once the flow in the chamber is turbulent.The fast Fourier transform of the signal showed that the dominant mode is at the resonance frequency of the combustion chamber.This result sheds light on a very important source of self-excited combustion instabilities.Furthermore the LES can provide not only the damping ratio for the analytical model but the eigenfrequency of the resonator also.

Model of GPS IF Signal and Its Simulation

A GPS IF signal computer simulation method is proposed in this article. The carrier Doppler frequency and the total propagation and delay time can be modeled or calculated with the input GPS satellite ephemeris file. The simulated GPS IF signal outputs to a text file for post-processing and analysis. The simulation signal spectrum is compared with the received real GPS IF signal spectrum, and the correctness of the simulation result is verified.

Flow computations of multi-stages by URANS and flux balanced mixing models

The quasi-steady methods based on mixing models have been widely applied to flow computations of turbomachinery multi- stages in aerospace engineering. Meanwhile, the unsteady numerical simulation has also been used due to its ability in obtaining time-dependent flow solutions. In the paper, two different mixing treatments and the corresponding flux balanced ones are presented to exchange the flow solutions on the interfaces between adjacent blade rows. The four mixing treatments are then used for flow computations of a subsonic 1.5-stage axial turbine and a quasi-l.5-stage transonic compressor rotor. The results are compared with those by unsteady numerical method, which is implemented by using the sliding mesh technique. The effects of the quasi-steady and unsteady computation methods on the conservation of flow solutions across the interfaces are presented and addressed. Furthermore, the influence of mixing treatments on shock wave and flow separation of the transonic compressor rotor is presented in detail. All the results demonstrate that the flux balanced mixing treatments can be used for multi-stage flow computations with improved performance on interface conservation, even in the complex flows.