复杂地形下风力机尾流数值模拟研究和激光雷达实验对比

以CFD数值计算和实验相结合的方法,对处于中国西南某多山地区陆上风电场的尾流特性进行研究,验证不同数值方法在复杂地形的适用性。首先采用2台激光雷达,测量目标风力机一个月内的自由来流风速和尾流廓线,在地形上坡加速效应下,不同大气稳定度下目标风力机的自由来流风速廓线均呈负梯度。然后分别采用经典致动盘和改进致动盘法,模拟目标风力机在主风向下的尾流发展。不同于只有风速与压降关系的经典致动盘法,改进致动盘法更考虑了叶片几何和气动参数(尺寸信息、攻角、桨距角、升阻力系数等)。通过与后置激光雷达尾流测试结果对比,这2种基于CFD技术的数值模拟方法,计算网格相同,计算时间相当,且均能较好地模拟因为复杂地形而引起的尾流偏转;其中改进致动盘的尾流形状与激光雷达相似,速度亏损也更接近激光雷达结果。因此,改进致动盘法更适合于复杂地形条件下风场模拟,较好平衡了计算的效率与精度。     

Terrain classification and adaptive locomotion for a hexapod robot Qingzhui

Frontiers of Mechanical Engineering - Legged robots have potential advantages in mobility compared with wheeled robots in outdoor environments. The knowledge of various ground properties and...     

基于IDL的地形三维可视化系统的研制

利用IDL语言强大的数据处理与图形显示功能,应用组件编程技术并结合数字摄影测量原理,对立体航空影像对进行数字影像处理,并通过内插计算快速生成数字高程模型。在此基础上运用可视化技术实现三维可视化显示及简单的可视化分析,从而完成了地形三维可视化系统的研制。     

守望形胜·因借地景——浅山区乡村景观 规划空间控制的方法研究

以探讨中国传统营造中“模数化”的空间规划控 制方法在浅山区乡村景观规划中的应用为核心，尝试将传统 营造方法转译于现代实践当中，以期改变浅山区乡村景观空 间控制的无序性和规划与自然山水环境割裂等问题。在传统 “模数化”规划方法的指引下，提出理想情况下浅山区乡村 景观规划“守望形胜、因借地景”2个层面的空间控制路径和 “胜”“势”与“视”3个层级的模数控制，并将其灵活运用 于嵩山浅山区金银花溪乡村景观规划项目的空间规划控制当 中，旨在激发传统营造的现代应用价值，构建浅山区乡村景观 空间呈现内外联动、互通共融、协调统一的风景整体。     

耕地后备资源评价中地形坡度指标获取方法分析

"人多地少"是我国的基本国情,耕地的大量抛荒及不合理使用导致我国耕地资源严重不足。为了缓解国家粮食安全问题,耕地后备资源成为了耕地的重要补充来源,也是实现占补平衡的保障。地形坡度作为评价指标必不可少的评价因子,文章对其获取方法进行了分析研究。利用GIS技术为支撑,通过对不同类型数据处理分析实现地形坡度指标值的获取,并结合数据处理规则,研究数据快速可行的处理方法,为今后相关工作提供技术支持及参考依据。     

闽东火山岩地区银矿成矿规律

本文论述了福建东部火山岩地区银矿的成矿地质条件、分布规律及成矿作用，建立了区域成矿模式。     

改建铁路增建线路段旅客列车设计速度选择

通过对影响改建铁路增建第二线路段旅客设计行车速度选择的因素的分析，从路网意义、运输需求、地形条件、运营条件、经济合理性等方面进行了论述，提出了合理选择增建第二线路段设计速度的思路和原则，达到了指导选择增建第二线路段设计速度的目的。     

Les dépôts morainiques holocènes de la zone axiale pyrénéenne: approche déterministe de leur instabilitéà Verdun sur Ariège, (Pyrénées centrales, France)

This paper reports a study of the historic instability of the till deposits in an area of the central Pyrenees between France and Spain upslope of the town of Verdun. The object of the work was to create a model based on the geomorphological and geological mapping of landslides and a geotechnical survey of the instability of the whole of the mountainous slopes of the Domanial Verdun area. The detailed mapping allows the historic landslides to be distinguished from the more recent/active movements which involve volumes of 100,000 to 400,000?m³ of material. In addition, it was possible to assess the areal percentage of the actively slipping zones (5%) compared to the historic slide zones (12%) and the stable areas (78%). Following the European classification, two types of slides were identified in the Verdun study area: (1) historic rotational slides and (2) active translational slides located in the Verdun area at between 1000 and 1250?m altitude. The stability was calculated using the classic "method of slices", subdividing the slipped zone into vertical slices along a suitable cross section. The so-called factor of safety (F) was determined by dividing the moments of resisting forces (M_R) by the moments of driving forces (M_D). The state of limiting equilibrium has a "factor of safety" of 1. The physical parameters of the till deposits of Verdun were established as: unit weight γ=24.9?kN/m³ (calculated using the percentage of gneissic blocks contained in the tills) and porosity n=0.24. The results of 15 triaxial tests in a gravelly sand matrix were plotted in a Lambe diagram following a linear regression model [x=(σ₁+σ₃)/2 and y=(σ₁–σ₃)/2 with sin?φ′ =tan?θ]. From this the friction angle φ′=33°±3 and c′=45±5?kPa were established. The factor of safety calculated for the moraine deposits in the historic slides was 1.44 without water (Hw=0). With a height of water of 7?m, representing 85% of the till thickness, this was reduced to F=1. To achieve a factor of safety of 1.3, the maximum water level within the till should not exceed 2.5?m, representing 65% of the till thickness. Similarly, the factor of safety was calculated for the active slides of another area (shown as section 4 in Fig.?3 in the paper). Using slice number 9 from the middle of the slide, the factor of safety was 1.08 when the height of the water was taken as 90% of the till thickness. This high calculated factor of safety for the height of water is consistent with the slow movement of the actual slides. However, a lower internal cohesion of the till deposits or the presence of a weathered zone would decrease the factor of safety from 1 to 0.8. It is also possible that other parameters, such as the regional seismic activity, could have been sufficient to initiate movement (F<1) during the last 50?years. It is of note that the map of seismic activity shows that more than a 100 earthquakes with magnitudes greater than 3 have occurred in the central Pyrenees since 1660. The paper emphasises the importance of high-quality mapping which identifies and classifies areas of historic and recent instability. From this, a single geotechnical model to calculate the stability can be established. The level of the water is shown to be the critical parameter and of more significance than the variations in the effective friction angle, which itself is more important than variations in the effective cohesion. With this information it is possible to determine those areas where some form of stabilisation and/or drainage of the till deposits is necessary.     

基于数字高程模型的输电线路虚拟地形绘制优化算法

针对现有输电线路仿真培训系统复杂地形和大规模场景的建模问题,研究了基于数字高程模型(DEM)的虚拟地形绘制优化算法.通过采集输电线路走廊位置和范围内的地形高程数据,结合分治算法和流水线技术实现Delaunay三角网的并行构建.并针对高斯曲面方程拟合三角形表面中的参数问题,提出了基于遗传算法的最优参数选择方法,降低了地形表面的整体误差.在Qt平台上实现了输电线路真实场景的三维可视化重构.仿真结果表明,本算法有效实现了输电线路真实地形的虚拟可视化,提高了虚拟场景的还原度和沉浸感.     

工程车辆双桥油气悬架性能对比仿真分析

通过分析全路面起重机双桥油气悬架组的液压系统油路图,建立双桥油气悬架组的7自由度数学模型,分析并联式和独立式双桥油气悬架模型主要区别,并利用AMESim仿真软件建立并联式和独立式双桥油气悬架仿真模型。对比分析了两种悬架系统的压力、轮胎动载荷、垂直加速度等参数的最大值,得出并联式悬架组的性能指标要优于独立双桥悬架的结论。