ExVis and wind tunnel experiment data

Visualization specialists and aeroscientists at NASA Ames collaborated in investigating how information technology can improve the aeronautical design process. The author discusses ExVis software tool created to support interactive display and analysis of data collected during wind tunnel experiments     

基于LSTM的风洞设备健康状态评估方法研究

针对风洞设备健康状态评估中特征提取困难、量化算法复杂等问题,提出了一种基于深度学习的健康度评估方法,利用正常状态样本数据训练LSTM编解码器网络并构建特征空间,利用测量数据特征向量与特征空间的欧氏距离衡量健康状态的退化程度,从而高效地实现了系统或设备的健康状态量化评估;经风洞试验室轴流风机转子不平衡故障、长轴轴承裂缝故障等两个数据集进行验证,取得了与设备工作状态一致的健康度评估值,具有很强的工程应用价值。     

一种自动校准多风表的风洞检测试验装置

针对传统风表校准方式需多次手动调节风量、操作复杂、人工读数与绘图费时费力且校准精度低等问题,设计了一种自动校准多风表的风洞检测试验装置,介绍了该装置的结构及检测试验原理。试验结果表明,该装置风流稳定,可自动调节风量,操作简单,可1次校准多个风表,校准精度高,并能对校准结果进行记录、存储、处理,适合于低、中、高3档多风表自动校准。     

高速风洞微型测量系统研制及应用

研制了一种高速风洞微型测量系统,由电气接口模块、增益控制模块、低通滤波模块、扫描采集模块、主控模块、LAN总线接口模块组成,实现了电压信号放大、低通滤波、模数转换、数据处理与分析等功能,静态校准结果表明关键性能指标与风洞常规测量系统相当,满足风洞试验信号采集需求。将该系统成功应用于2.4米跨声速风洞标模测力试验,开展了对比试验以及测量精度试验,并与常规测量系统试验结果进行了对比,试验结果表明微型测量系统精度和稳定性满足试验要求,能够适应高速风洞应用环境。     

大型风洞PIV粒子发生装置研制

示踪粒子量不足是制约大型风洞PIV试验的关键和难点问题,结合大型风洞的实际情况,通过原理设计、分析计算和试验验证,成功研制了基于加热蒸发原理的大流量粒子发生器,并应用到了大量的工程实践中;结果表明,在大型风洞PIV试验中,采用经济性好的油基材料加热蒸发的方式,可持续、足量、均匀地供应示踪粒子,是一种较好的粒子产生方式;另外,在粒子发生装置设计时,应充分考虑实际所需粒子流量,并针对选择的粒子材料的理化特性开展计算分析.     

超大型连续式跨声速风洞地震安全分析

采用有限元法对某超大型连续式跨声速风洞进行地震安全分析。使用ANSYS建立整体结构模型并施加实际约束,为确保计算精度和计算效率,采用实体壳单元SOLIDSHELL进行网格划分;依据JB/T 4710—2005《钢制塔式容器》和仿真模态分析进行水平地震力计算;基于JB 4732—1995《钢制压力容器——分析设计标准》对风洞进行强度评定。计算结果表明：在地震载荷作用下,该风洞主体结构强度安全裕量较大,其结构形式合理可靠。     

基于FIR神经网络的风电场虚拟风速传感器

风电机组风速传感器易发故障,故障可能导致机组安全风险和发电量损失。针对现行的故障处理方法因与机组控制策略紧密耦合而日益面临挑战,提出了一种基于数据处理的虚拟风速传感器原理与方法：由风电场上风向测量风速计算下风向推算风速,用推算风速取代故障传感器。着重讨论了基于FIR神经网络的推算风速计算方法和计算模型,探讨了系统实现的关键技术。实验证明了虚拟传感器的误差在机组控制系统可接受的程度内。提出的方法独立于机组自身属性,具有普遍适用性,可部署在任意类型的场,在物理传感器故障时向机组提供风速信号,支撑风电机组持续安全运行。     

风洞测控技术展望

介绍风洞测控系统在工控技术、总线技术、嵌入式系统、数采系统、传感器技术等方面的发展。     

基于虚拟检测技术的隧道交通参数检测方法研究

针对隧道监控中的交通参数检测问题，提出了一种基于虚拟检测技术的隧道参数检测方法，挖掘隧道几何模型，定义虚拟线圈和虚拟检测线，根据虚拟线圈感应变化，检测隧道中的车流量；通过拟合投影关系，检测车速，实验结果表明：该方法具有较高检测概率，满足系统的实时要求，并且具有很高的抗噪声干扰能力。     

风洞系统非线性块状结构模型

本文将非线性块状模型的建模思想引入风洞系统模型的建立过程中,针对主排气阀和栅指电液伺服机构具有死区非线性特性,分别用含有死区输入的Hammerstein块状模型描述其动态特性,将主排气阀和栅指机构的输出作为风洞流场的输入,建立两输入两输出多变量耦合动态模型.两个独立的Hammerstein子模型与线性动态耦合的风洞流场模型串联构成一个非线性多变量块状模型.采用自适应加权递推辨识算法在线辨识Hammerstein子模型参数,采用带有遗忘因子的递推最小二乘法辨识风洞流场模型参数.仿真与风洞现场测试结果验证了本文方法的有效性.     

风洞天平实时载荷监测方法研究

针对当前风洞天平应用环境越来越复杂,但却缺乏有效的安全监测手段的现状,提出了一种基于应力叠加原理的风洞天平实时载荷监测方法;首先,分析天平受力情况,基于工程经验、天平应力集中位置以及应变计粘贴位置等因素划分危险载荷监测区域;其次,基于有限元方法对天平进行网格划分,计算载荷监测区网格节点的应力影响系数;最后,结合天平六元信号输出实时计算载荷监测区的节点应力值,并与有限元理论计算结果和静态校准加载结果进行对比验证;验证结果表明,有限元理论验证准度优于0.02%,静态校准加载验证阻力元准度优于10%,其余5元准度均优于4%;证明本方法具有较高的计算准度,能够满足风洞天平实时载荷监测的使用需求,具有较高的实际应用价值。     

Exact solution for wind tunnel interference using the panel method

Wind tunnel wall interference effects on lifting and non-lifting bodies are computed here for incompressible two-dimensional flows. The flows around bodies under consideration are computed by a panel method using linearly varying vortex distributions. The method is regarded as an exact numerical method. Also to exactly compensate for the wind tunnel wall, we use the method of images of the complete body in the wind tunnel. The image system consists of two cascades which extend infinitely on both sides of the wind tunnel. Thus, the exact wind tunnel wall interference effects are obtained for circular and elliptic cylinders, NACA 23012, NACA 64A010 and NACA 0010 airfoils. The velocity distributions and lift coefficient variations are presented for different blockages. The effects of airfoil incidences and the relative proximity of the two walls are also investigated. The present analysis has given rise to some results which otherwise would not have been possible by earlier existing very approximate methods. Wind tunnel walls are found to change the circulation around the body in the wind tunnel. This effect is further accentuated if we either change the incidence or change the relative proximity of the wind tunnel walls.     

Virtual wind tunnel: An alternative approach for the analysis of bridge behaviour under wind effects

The study of bridge responses under wind-induced loads is based upon full aeroelastic model testing or hybrid methods which use section model tests and subsequent computer analysis. Both methodologies present several strong points and some shortcomings, specially related with the visualization of the bridge dynamic behaviour. Nowadays, advances and improvements in computational power and computer aided design technologies make possible a new way towards the feasible design of long span bridges considering its aerodynamic and aeroelastic behaviour. The virtual wind tunnel (VWT) technique developed by the authors joins together accurate section model testing with computer aided design in order to obtain a detailed computer visualization of the complete bridge behaviour under wind flow. The results obtained for the Tacoma Narrows Bridge and the Messina Strait Bridge are presented.     

Numerical study of the injection process in a transonic wind tunnel: The numerical details

Numerical prediction of an injection process was successfully performed. The physical problem corresponds to the mixing of a number of parallel supersonic jets with a subsonic main stream, in the presence of solid walls. In practice, this arrangement is to be used as a boosting device in a transonic wind tunnel, with the ultimate objective of extending the tunnel’s envelope without penalizing the main compressor. Five supersonic nozzles are installed at the floor and five at the ceiling of the transition module’s entrance section. Due to the great difference between cross-sectional typical lengths of nozzles and tunnel, the numerical tool has to have a three-dimensional capability. The core of the code is an adaptation of the finite-difference diagonal algorithm, and turbulence effects are properly tackled by the use of the Spalart and Allmaras one-equation scheme. Some simplifications were adopted in order to render the problem minimally tractable, especially in this initial numerical simulation stage, which is the reporting objective of this article. Albeit this, and due to the magnitude of the problem in hand, these simplifying initiatives were not sufficient to bring the calculations down to a scale of reasonable computer costs. Hence, a sequence of grids, coupled with a division of the computational domain, was adopted. Boundary conditions were thoroughly worked, especially the ones related to the domain of calculation’s entrance plane. This plane is important because of the many viscous gradient regions that project against it. Among the many settings under which a tunnel can operate there is one defined as the “design condition”, or else as the “design point”, as it is sometimes called. For a tunnel equipped with an injection system, the design point asks (besides many other specifications) for equal static pressures at the section where the supersonic jet meets for the first time the main stream coming from the tunnel circuit. We have simulated five different operating settings of the tunnel and among them the design condition. Therefore, we have results for the design as well as for many off-design points. The idea was to simulate the many tunnel settings and also to test the code’s ability to handle all these different situations. The code was duly validated and verified, and in the sequel the steady flow field in the mixing region was calculated. Many interesting and very important results were obtained, among which we would point out the existence of compression and expansion domes at the supersonic regions, the calculation of the many engineering parameters related to the injection process, and especially the determination of the injection’s gain threshold.     

单层平面索网玻璃幕墙数值风洞风载荷分析

针对现行幕墙设计规范没有明确规定单层平面索网幕墙体系的风载荷计算的问题,以某大厦裙房幕墙为研究对象,用ADINA分析考虑流固耦合作用的玻璃 索网体系风振响应分析,并与通常采用的等效静风载荷方法得到的结构风效应比较.分析表明,对于非线性的索网玻璃幕墙结构,现行载荷规范采用的等效静风载荷方法会导致偏于不安全的设计计算结果.     

基于InTouch的风洞自主式维修保障系统监控软件设计

信息技术的发展促进了组态软件的成熟与完善,在工业控制、轨道交通、水电供给乃至武器装备运行控制等领域得到广泛应用。为了配合风洞自主式维修保障系统,提升风洞的维修保障能力与实时的在线监测能力,通过InTouch组态软件设计并应用了可靠、稳定的数据接口;搭建了运行流畅、信息丰富、实时性好的监控软件;为风洞提供了良好的装备状态监测平台。其满足风洞自主式维修保障系统对信息监控及表达的一体化、自动化和可视化的要求,并成功应用在某型风洞中。     

High performance nonlinear adaptive control of temperature in cryogenic wind tunnel

A new nonlinear adaptive control method based on Immersion and Invariant (I&I) approach is proposed for the temperature control of a cryogenic wind tunnel. The proposed control method can be applied to wide range temperature operation of the tunnel by incorporating the nonlinear dynamic model of temperature into the controller design. By constructing globally stable nonlinear observer, and rendering an invariant and attractive manifold in the state space of plant and observer, the uncertain gain of known disturbance and unknown wind tunnel wall temperature are considered in the same manner within the adaptive I&I control frame. In the design, nominal heat transfer coefficient is deployed to avoid complicated design process involving nonlinear parameterization. This design leads to an adaptive output feedback stabilization control law for the temperature with guaranteed transient and steady performance, which exhibits reasonable robustness to time delay in the control input channel and other uncertainties. The analysis and simulation show the effectiveness of the proposed control methodology.     

Complex automation of aerodynamic experiment in T-106 transonic wind tunnel

The system of complex automation of aerodynamic experiment in T-106 TsAGI transonic wind tunnel is presented. Data acquisition processes, as well as control processes for the model’s Mach number and angle of attack are automated on the basis of new data acquisition and control system involving IVK M2 data acquisition software package and VMIC control software package. The results of balance and pressure experiments (and of the combined ones) are presented. Stages of experimental results processing are described.     

风洞试验绳牵引并联机器人高精度控制仿真

针对一种应用于风洞试验的六自由度绳牵引并联机器人系统,研究其支撑的飞行器模型高精度运动控制问题.首先从系统运动学角度出发,针对绳与飞行器模型之间可能出现的干涉问题,基于绳系时变结构的概念,建立了一个单自由度时变运动方程.构建了驱动系统与飞行器的动力学模型,设计了基于飞行器位姿直接反馈的比例微分控制器,并进行稳定性分析.最后,分别以单自由度和多自由度运动为例,进行绳系结构非时变系统与时变系统的数值仿真.分析结果表明,本文所建立的数学模型是正确可行的,采用一种单自由度时变结构可以有效避免俯仰运动干涉.通过合理设置预紧力,可以避免运动过程中牵引绳松弛.采用PD控制率可以实现飞行器模型的高精度运动控制,从而满足风洞试验的实际应用需求.     

一种基于组件的风洞通用测控平台设计

为了提高风洞测控系统及其软件的可扩展性和重用性,缩短软件开发周期,从风洞测控系统的特性与需求出发,综述了风洞测控软件通用化的现状,并基于面向对象思想和系统架构设计理念,提出了组件化风洞测控软件平台的层次结构,分析了用户定制层和功能实现层的组件划分、组件通信模式/接口和组件封装,讨论了基于组件的风洞测控平台原型系统设计,为风洞测控系统软件的进一步通用化提供了一种思路和方法。