Imager sCMOS PIV相机

采用LaVison公司的DaVis软件平台，通过阴影发成像和粒子成像测速分析，对脉冲流场在USP溶解仪中引起的水动力复杂性，进行了研究。

An experimental study has been conducted to investigate the static and wind-on performance of two in-house-developed polymer-based pressure-sensitive paints. Platinum tetrakis (pentafluorophenyl) porphyrin and tris-bathophenanthroline ruthenium II are used as the luminophores of these two polymer-based pressure-sensitive paints. The pressure and temperature sensitivity and the photo-degradation rate of these two pressure-sensitive paints have been investigated. In the wind tunnel test, it was observed that the normalised intensity ratio of both polymer-based pressure-sensitive paints being studied decreases with increasing the number of wind tunnel runs. The exact reason that leads to the occurrence of this phenomenon is unclear, but it is deduced that the luminophore is either removed or deactivated by the incoming flow during a wind tunnel test.

The molecular structure of the interfacial regions of aqueous electrolytes is poorly understood, despite its crucial importance in many biological, technological, and atmospheric processes. A long-term controversy pertains between the standard picture of an ion-free surface layer and the strongly ion specific behavior indicating in many cases significant propensities of simple inorganic ions for the interface. Here, we present a unified and consistent view of the structure of the air/solution interface of aqueous electrolytes containing monovalent inorganic ions. Molecular dynamics calculations show that in salt solutions and bases the positively charged ions, such as alkali cations, are repelled from the interface, whereas the anions, such as halides or hydroxide, exhibit a varying surface propensity, correlated primarily with the ion polarizability and size. The behavior of acids is different due to a significant propensity of hydronium cations for the air/solution interface. Therefore, both cations and anions exhibit enhanced concentrations at the surface and, consequently, these acids (unlike bases and salts) reduce the surface tension of water. The results of the simulations are supported by surface selective nonlinear vibrational spectroscopy(VSFG), which reveals among other things that the hydronium cations are present at the air/solution interface. The ion specific propensities for the air/solution interface have important implications for a whole range of heterogeneous physical and chemical processes, including atmospheric chemistry of aerosols, corrosion processes, and bubble coalescence.

A new compact micro-lens optical system has been developed to produce a 7 x 7 multiline optical grid for Hydroxyl Tagging Velocimetry (HTV). These lines provide additional spatial information and aid the software tracking of the flowfield by increasing its resolution. Single-photon photodissociation of groundstate H2O by a ~193-nm ArF excimer laser “writes” a 7 x 7 beam molecular grid with very long gridlines of superequilibrium OH and H photoproducts in either room air flowfields or in H2-Air flames due to the presence of H2O vapor. The displaced OH tag lines’ positions are revealed through fluorescence by A2Σ+ (v′= 0) ← X2Πi (v″ = 0) OH excitation using a ~308 nm pulsed frequency-doubled dye laser. A time-of-flight software (DaVis 6.0 Stereo PIV/PTV, LaVision, GmbH) determines the instantaneous velocity field. HTV tag lifetime comparisons between experimental results and theoretical predictions are discussed.

采用LaVision的sCMOS相机构成的PIV和PLIF测量系统，对双射流混合流进行了流体速度场和双色PLIF温度场测量研究。

双路染料激光构成的多参量激光诊断系统。进行了CARS/CO-LIF/磷光测温/OH-PLIF组合测量，CH2O-PLIF 和 OH-PLIF同时测量，以及拉曼测量尝试。研究了火焰壁面相互作用

利用LaVision公司的科研型CMOS相机sCMOS和Photron公司高速相机Phontron FASTCAM SA-X2加装LaVision公司的高速图像增强器IRO进行了飞秒激光电子激发标志-Femtosecond laser electronic excitation tagging (FLEET)测速实验，并进行了性能和结果对比分析。

采用LaVision公司由科研型CMOS相机和DaVis软件平台构成的粒子成像测速系统，对在泰勒-库埃特湍流中，使用疏水内筒实现气泡减阻的方法进行了实验测量研究。

采用LaVision公司的FlowMaster粒子成像测速系统。测量了超音速气流作用下，机翼表面的流场。研究了火花放电产生局部快速加热对分离点位置的影响。

采用德国LaVision公司的DaVis软件平台和四台高速相机，构建了时间分辨层析3D3C速度矢量场测量系统，对风洞中的空气流场进行了测量，并使用层析成像重建和三角测量的组合进行双帧粒子跟踪三维测速。

采用三台LaVision公司的ImagerProHS高速相机，加上DaVis7.4软件平台，对风洞中的翼型进行了时间分辨层析PIV测量，并用一种新型的高效准确的MTE-MART算法，对结果进了分析处理，并比较了这种算法与其它多种算法的性能。

采用NewWave公司GeminiII型Nd:YAG 双脉冲PIV激光器作光源。1016 × 1008 pixel 分辨率Kodak ES 1 Megaplus型相机做成像部件。LaVision的DaVis 软件平台做全部的数据处理，对跨音速矩形腔体流动中锯齿形阻流板性能的比例效应，进行了实验测量和研究。

采用LaVison公司的智能成像测量系统中的平面激光诱导荧光测量方法，用丙酮做示踪剂，研究了超音速气体引射器中的混合过程。

This paper describes the full scale tests for air flows in a test chamber subject to heat loads generated by human occupancy and equipment. The Particle Image Velocimetry (PIV) technique was used to investigate buoyancy-driven flows near the human thermal manikin “Victoria”. Based on the experimental facility details, a full scale 3-D CFD model of the test facility was generated. The results obtained from the CFD simulation were compared with data obtained from the PIV results. Results compare very well and demonstrate the potential usefulness of PIV as a CFD validation technique.

Low-rise buildings located in the urban areas are generally surrounded by buildings of similar size. The interference of surrounding buildings has been found to be significant on wind loads in straight-line winds. In this study, systematic experiments of tornado-induced wind loads and flow patterns around a typical low-rise gable-roof building with different layouts of surrounding buildings were carried out in a laboratory. Effects of spacing, height ratios of the surrounding buildings to the test building and specific building orientations were considered. The results indicate that the reduction of the horizontal load is caused by sheltering effect from the surrounding buildings. The uplift load, however, could increase or decrease dependent on building orientation, layout and the type of the surrounding buildings. The complicated flow patterns around the test building are discussed and correlated to the wind loads. This study would improve the understanding of tornado-induced loads on a low-rise gable-roof building

采用LaVision公司由4台sCMOS型相机和DaVis8.2软件平台构成的大视场2D2C粒子成像测速系统，对破漏层模型的流程进行了初步的实验分析。

采用LaVsion公司特色的增强型CCD相机为核心部件，构成平面激光诱导荧光测试系统。利用该系统对火花塞引燃发动机内冷焰组分的传播进行了可视化研究。

采用LaVision公司的增强型CCD相机对燃烧过程中的重要中间产物甲醛的浓度分布进行了定量测量。采用了LaVision公司独特的激光诱导荧光燃烧火焰分析测试系统Flame-Master

利用LaVision公司成熟可靠的喷雾局域粒径测量系统PartileMaster-Shadowgraphy 和喷雾全局粒径分布测试系统SprayMasterD32. 对汽车发动机尿素-水溶液喷射的喷雾几何参量和粒径分布进行了实验研究。可以用于汽车选择催化还原脱氮（SCR DeNOx）系统分析：两相流动和喷雾/壁面相互作用建模

Modern spark-ignited internal combustion engines have intake ports designed to introduce high levels of so-called “tumble” charge motion. Correspondingly high shear rates can lead to high fluctuations and turbulence within the combustion chamber. A suitable test case to characterize the intake flow is a steady-state flow bench. Although routinely used in the engine development process to determine the global discharge coefficients, only a few detailed numerical and experimental studies use this test case to analyze the flow in the vicinity of the valve with high spatial and temporal resolution. In this paper, we combined highly resolved two-dimensional, two-component Particle Image Velocimetry (PIV) measurements and numerical simulations using a Detached-Eddy Simulation (DES) model to characterize engine-relevant flow features on a flow bench. The spatial resolution of numerical simulations on two different grids is assessed and compared to that of the PIV measurement. The results of simulations and experiment are then compared in terms of their mean and fluctuation velocity fields and the jet orientation. A detailed study of the area around the valve seats investigates the validity of wall functions in this region. Finally, we examine structures induced by vortex-shedding at the valve stem and if they are transported into the combustion chamber.

采用LaVision的sCMOS型CCD相机和200毫焦的PIV激光器，采用水下潜望镜形式拍照，采用荧光示踪粒子成像测速（PIV )方法跟踪掠过水体表面薄膜流场的涡核。

We have adapted a standard Fourier-transform infrared (FTIR) spectrometer (Thermo-Scientific Nexus 670) for in-cylinder measurements of gas spectra. During engine operation, the engine shaft encoder signal is logged continuously along with the FTIR’s He–Ne laser signal and infrared interferogram signal. The engine piston and FTIR mirror move in an uncorrelated fashion, so that after many minutes of engine operation, a complete interferogram is populated at each piston position. Afterward, the data are compiled into a series of spectra versus crank-angle degree. Here, we present a near-infrared H2O thermal emission spectrum measured through a fiber-optic spark plug connected to an engine

This paper deals with the experimental investigations of the in-cylinder tumble flows in an unfired internal combustion engine with a flat piston at the engine speeds ranging from 400 to 1000 rev/min., and also with the dome and dome-cavity pistons at an engine speed of 1000 rev/min., using particle image velocimetry. From the two-dimensional in-cylinder flow measurements, tumble flow analysis is carried out in the combustion space on a vertical plane passing through cylinder axis. To analyze the tumble flows, ensemble average velocity vectors are used and to characterize it, tumble ratio is estimated. From the results, generally, we have found that tumble ratio varies mainly with crank angle position. Also, at the end of compression stroke, average turbulent kinetic energy is more at higher engine speeds. We have also found that, at 330 crank angle position, flat piston shows an improvement of about 85 and 23% in tumble ratio, and about 24 and 2.5% in average turbulent kinetic energy compared to dome and dome-cavity pistons respectively.

The flow around a ship at yaw angles beyond those encountered during manoeuvres has not been the subject of much research reported in the literature. These conditions are particularly important for an escort tug, since it uses large yaw angles to generate hydrodynamic forces that are used to control a ship (normally a tanker) in the event of an emergency. This paper presents CFD predictions for the flow around an escort tug at a yaw angle of 45 degrees and compares them to PIV measurements of the flow patterns. The CFD code predicts the essential features measured within the flow, such as the separation of the flow from the upstream bilge, and the formation of a large vortex generated by the low aspect ratio fin. The predicted vectors were compared with the measured ones using a numerical technique, and the agreements were found, on average, to be within 10%. This level of agreement was within the estimated uncertainty of the PIV system used for the experiments.

Zooplankton feed in either of three ways: they generate a feeding current, cruise through the water, or they are ambush feeders. Each mode generates different hydrodynamic disturbances and hence exposes the grazers differently to mechanosensory predators. Ambush feeders sink slowly and therefore perform occasional upward repositioning jumps. We quantified the fluid disturbance generated by repositioning jumps in a mm-sized copepod (Re ~ 40). The kick of the swimming legs generates a viscous vortex ring in the wake; another ring of similar intensity but opposite rotation is formed around the decelerating copepod. A simple analytical model, that of an impulsive point force, properly describes the observed flow field as a function of the momentum of the copepod, including the translation of the vortex and its spatial extension and temporal decay. We show that the time-averaged fluid signal and the consequent predation risk is much less for an ambush feeding than a cruising or hovering copepod for small individuals, while the reverse is true for individuals larger than about 1 mm. This makes inefficient ambush feeding feasible in small copepods and is consistent with the observation that ambush feeding copepods in the ocean are all small, while larger species invariably use hovering or cruising feeding strategies.

Many marine organisms have complex life histories, having sessile adults and relying on the planktonic larvae for dispersal. Larvae swim and disperse in a complex fluid environment and the effect of ambient flow on larval behavior could in turn impact their survival and transport. However, to date, most studies on larvae–flow interactions have focused on competent larvae near settlement. We examined the importance of flow on early larval stages by studying how local flowand ontogeny influence swimming behavior in pre-competent larval sea urchins, Arbacia punctulata. We exposed larval urchins to grid-stirred turbulence and recorded their behavior at two stages (4- and 6-armed plutei) in three turbulence regimes. Using particle image velocimetry to quantify and subtract local flow, we tested the hypothesis that larvae respond to turbulence by increasing swimming speed, and that the increase varies with ontogeny. Swimming speed increased with turbulence for both 4- and 6-armed larvae, but their responses differed in terms of vertical swimming velocity.

The measurement of blood-plasma velocity distributions with spatial and temporal resolution in vivo is inevitable for the determination of shear stress distributions in complex geometries at unsteady flow conditions like in the beating heart. A nonintrusive, whole-field velocity measurement technique is required that is capable of measuring instantaneous flow fields at submillimeter scales in highly unsteady flows. Micro particle image velocimetry ðmPIVÞ meets these demands, but requires special consideration and methodologies in order to be utilized for in vivo studies in medical and biological research. We adapt mPIV to measure the blood-plasma velocity in the beating heart of a chicken embryo. In the current work, bio-inert, fluorescent liposomes with a nominal diameter of 400nm are added to the flow as a tracer. Because of their small dimension and neutral buoyancy the liposomes closely follow the movement of the blood-plasma and allow the determination of the velocity gradient close to the wall. The measurements quantitatively resolve the velocity distribution in the developing ventricle and atrium of the embryo at nine different stages within the cardiac cycle. Up to 400 velocity vectors per measurement give detailed insight into the fluid dynamics of the primitive beating heart. A rapid peristaltic contraction accelerates the flow to peak velocities of 26 mm/s, with the velocity distribution showing a distinct asymmetrical profile in the highly curved section of the outflow tract. In relation to earlier published gene-expression experiments, the results underline the significance of fluid forces for embryonic cardiogenesis. In general, the measurements demonstrate that mPIV has the potential to develop into a general tool for instationary flow conditions in complex flow geometries encountered in cardiovascular research.

采用LaVision公司的时间分辨粒子成像测速系统，对水模拟发动机模型中流场的涡流和滚流两种流动形态进行了测量和研究。

采用LaVision的科研级sCMOS相机，对用3D打印技术制成的微流提探头的流场特性进行了实验测量。

采用LaVision的DaVis 8.3.0软件平台，加上PTUX时序控制器，四台 s'CMOS相机，构成了2D2C平面和3D3C体视粒子成像测速系统。并利用该系统对轴对称欠扩展喷射流过邻近相伴表面的流体-结构相互作用过程进行了实验研究

采用4台高速相机和LaVision的DaVis8.2.0软件平台，构成一套时间分辨拉格朗日视角3D3C粒子跟踪测速系统。对拖曳水池中的翼型进行了实验测量，并进行了基于运动方程作为物理约束的拉格朗日数据梯度估算。

采用立陶宛Ekspla公司的PL2231C-20, 20 Hz, 80 ps,532 nm, >15 mJ/pulse 激光器做光源，采用LaVision公司的sCMOS (2560 x 2160 pixels, 6.5 gm pixel pitch,16-bit depth) 相机。采用四波混频，相位共轭镜补偿等技术实现消除激波密度不均匀性干扰的相干成像。

采用美国Artium公司的相位多普勒粒子干涉仪（PDI）和德国LaVision公司的喷雾测试系统SprayMaster对多注入角度喷雾进行了实验和计算模拟研究。

We introduce and test an experimental approach to simulate elastoplastic megathrust earthquake cycles using an analogue model and apply it to study the seismotectonic evolution of subduction zones. The quasi-two-dimensional analogue model features rate- and state-dependent elastic-frictional plastic and viscoelastic material properties and is scaled for gravity, inertia, elasticity, friction, and viscosity. The experiments are monitored with a high-resolution strain analysis tool based on digital image correlation (particle imaging velocimetry, PIV), providing deformation time series comparable to seismologic, geodetic, and geologic observations. In order to separate elastic and nonelastic effects inherent the experimental deformation patterns, we integrate elastic dislocation modeling (EDM) into a hybrid approach: we use the analogue earthquake slip and interseismic locking distribution as EDM dislocation input and forward model the coseismic and interseismic elastic response. The residual, which remains when the EDM prediction is subtracted from the experimental deformation pattern, highlights the accumulation of permanent deformation in the model. The setup generates analogue earthquake sequences with realistic source mechanisms and elastic forearc response and recurrence patterns and reproduces principal earthquake scaling relations. By applying the model to an accretionary-type plate margin, we demonstrate how strain localization at the rupture peripheries may lead to a seismotectonically segmented forearc, including a tectonically stable shelf and coastal high (<20% plate convergence accommodated by internal shortening) overlying the area of large megathrust earthquake slip. Fifty to 75% of plate convergence is accommodated by internal shortening in the slope region where earthquake slip tapers out toward the trench. The inner forearc region remains undeformed and represents a basin.

采用LaVision公司的FlowMaster-TR时间分辨粒子成像测速系统，体外测量了人工主动脉瓣上行主动脉血流流场，研究了功能不全的人工主动脉瓣对流场特性的影响。

采用LaVision的显微粒子成像测速系统，对二尖瓣机械心脏瓣膜铰链区模型的铰链区的流场进行了测量和分析。

In hemodynamics, the inherent intermittency of two-phase cellular-level flow has received little attention. Unsteadiness is reported and quantified for the first-time in the literature using a combination of fluorescent dye labelling, time-resolved scanning confocal microscopy, and micro-particle image velocimetry (μPIV). The near-wall red blood cell (RBC) motion of physiologic high-hematocrit blood in a rectangular microchannel was investigated under pressure driven flow. Intermittent flow was associated with (1) the stretching of RBCs as they passed through RBC clusters with twisting motions; (2) external flow through local obstacles; and (3) transitionary rouleaux formations. Velocity profiles are presented for these cases. Unsteady flow clustered in local regions. Extra-cellular fluid flow generated by individual RBCs was examined using submicron fluorescent microspheres. The capabilities of confocal μPIV post-processing were verified using synthetic raw PIV data for validation. Cellular interactions and oscillating velocity profiles are presented and 3D data are made available for computational model validation.

Over the past 15 years, coil embolization has emerged as an effective treatment option for cerebral aneurysms that is far less invasive than the long-standing convention of surgical clipping. However, aneurysm recurrence after coil embolization is not uncommon: recurrence rates as high as 50% have been reported in the literature. One factor that may contribute to recurrence after coiling is residual flow into the aneurysmal sac. At present, there is limited quantitative knowledge of the relationship between coil packing density and aneurysmal inflow. We present an in vitro fluid dynamic study of basilar tip aneurysm models that elucidates this relationship. At physiologically normal flow rates, we found that a packing density of 28.4% decreased aneurysmal inflow by 31.6% in a wide-neck model, and that a packing density of 36.5% decreased aneurysmal inflow by 49.6% in a narrow-neck model. Results also indicated that coiling reduced aneurysmal inflow more significantly at lower parent vessel flow rates, and that coiling reduced neck-plane velocity magnitudes more significantly for narrow-neck aneurysms. Our study provides novel quantitative information that could ultimately contribute to improved outcomes for patients with cerebral aneurysms by enabling more effective coil embolization.