three dimensional velocity field measurement

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Simultaneous measurement of 3D zooplankton trajectories and surrounding fluid velocity field in complex flows

Simultaneous measurement of 3D zooplankton trajectories and surrounding fluid velocity field in complex flows

We introduce here a combined tomographic PIV and 3D particle tracking velocimetry (PTV) technique based on two light sources to study turbulence – copepod interactions over a range of length scales. Tomographic PIV based on pulsed infrared light measures time- resolved fluid velocity on a volumetric Cartesian grid, whereas 3D PTV based on a steady white light source independently and automatically identifies and tracks discrete organisms within the same measurement volume without eliciting phototactic responses. This technique resolves small-scale interactions by determining the location and velocity of plankton as well as local fluid velocity gradients. At the same time, it provides plankton trajectories, plankton spatial distribution and fluid velocity variations over larger length scales. We demonstrate the method by determining copepod trajectories and local strain rates both upstream and downstream of a cylinder in cross flow where the flow in the downstream region is highly unsteady and three-dimensional. In addition, we illustrate the capability to extract zooplankton slip velocity such that, even for these small organisms, their drifting trajectory in unsteady flow can be different from those of fluid particles.
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Error analysis for a Static Convergent Beam Triple LIDAR

Error analysis for a Static Convergent Beam Triple LIDAR

Measurement of wind shear (changing wind speed with height) and wind veer (changing wind direction with height) are examples of where it is necessary to measure the three-dimensional variation of wind velocity through space. This may determine suitability of a site for wind turbine deployment. In summary the measurement of the three-dimensional volumetrically varying wind velocity vec- tor field offers numerous advantages to the wind industry, including that of better site assessment of damaging local conditions, better turbine site classifications (matching turbine strengths to site conditions), and better insurance and warranty conditions (ensuring turbines are operating within their design specifications). This may be achieved by a scanning converging beam triple LIDAR.
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Calculation of three-dimensional boundary layers on turbomachinery blades

Calculation of three-dimensional boundary layers on turbomachinery blades

Olsson (1962) carried out comprehensive measurements of the mean flow field on an axial compressor blade. The experiments were conducted in a stationary annular cascade. In order to eliminate the endwalls boundary layer, the endwalls of the cascade and the duct-walls approximately two chord-length upstream of the cascade were made of perforated material. The measurements of free-stream velocity were taken by using three-hole cobra-probe and five-hole direction probe. For velocity profiles inside the boundary layers, a specially made probe of the cobra-type was used. Details of the construction and measurement of these probes can be found in Olsson (1962). He reported that there are larger uncertainties in the crossflow measurements than that in the streamwise measurements. The uncertainty in the streamwise measurement (— ) was ±1.5
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Error propagation analysis for a Static Convergent Beam Triple LIDAR

Error propagation analysis for a Static Convergent Beam Triple LIDAR

It will be our objective in the remainder of this paper to gauge the effect of uncertainty (epistemic or otherwise), as a result of the perceived polar angles and measurements of the Doppler velocity components, on the value of the reconstructed velocity vector in Cartesian coordinates. This will be done by working with a metric commonly referred to as the error propagation formula, which is, in part, derived from a first order Taylor expansion of the output variable around some nominal input configurations. This sort of approach, which normally has to be established on a bespoke basis for the system at hand, has at least been alluded to in the work of Liu et al. (2018), Ni et al. (2016), and Wang et al. (2018).
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The interaction between fluid flow and ultra-hydrophobic surface in mini channel

The interaction between fluid flow and ultra-hydrophobic surface in mini channel

The micro visualization technique provided us the information about the air film thickness. We used the long distance microscopy to cover the whole velocity profile across the channel – 5 mm, and 8 mm. The basis of micro PIV technique is a laser beam, which illuminates the entire volume of the examined space. For illumination of the evaluated area NewWave Gemini Nd:YAG pulsed laser is used, energy of 120mJ per pulse length of 10 ns, wavelength 532 nm.The images are captured with Neo CMOS chip 5.5 MPixel size of 6.5 microns camera. Laser and camera system is controlled from a computer and synchronized with the external TimerBox.
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Three-dimensional temperature field measurement of flame using a single light field camera

Three-dimensional temperature field measurement of flame using a single light field camera

Various measurement techniques have been reported over the past decades for the 3-D temperature field measurement of flame, for instance laser-based diagnostics [3-5] and radiative imaging techniques [6-13]. Laser-based techniques are active measurement methods, which employ the measured scattering, absorption and fluorescent signals caused by the laser crossing the flame to derive the temperature [3-5]. For example, the fluorescence of the species (e.g., NO) excited with a laser is utilized in laser-induced fluorescence (LIF) thermometry. However, due to the complexity and high cost of the laser-based diagnostic systems, these techniques are generally unsuitable for the applications in hostile industrial environments. The limited power of lasers also limits the applicability of laser-based diagnostics. In radiative imaging technique, the visible radiation information is usually applied to measure the temperature fields of flames. This technique doesn’t require imposing external signal and hence they are simple in system setup compared with laser-based diagnostic system. For example, Hossain et al. [6-8] developed optical tomographic algorithms incorporating logical filtered back-projection and simultaneous algebraic reconstruction techniques to reconstruct the grey-level intensities of flame sections. The flame temperature distribution is obtained from the reconstructed grey-level intensities of the image based on the two color method. Zhou et al. [9-11] proposed a radiative imaging model which relates flame image with the temperature distribution based on conventional CCD camera. The 3-D flame temperature is then reconstructed using a Tikhonov regularization method to solve the model. Wang et al. [12] used HDR (high dynamic range) cameras to avoid the loss of information caused by overexposure
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Numerical simulation of ice accretion on a propeller blade

Numerical simulation of ice accretion on a propeller blade

A flow field has been created for each of the slices. As the geometry of the blade is fairly curled, all sections need their own mesh. In figure 5.1 the necessity for this is clearly visible as the geometry curls along with the apparent flow for the relative sections on the propeller blade. This is a slight indication that this approach could be right. The geometry also gets thinner on the outer parts of the blade, causing less distortion of the flow. But as also visible in table 5.2, the apparent velocity increases significantly. With this flow fields, the results have been examined using Multi-Ice. Firstly shown are the trajectory plots for the different sections. In figure 5.2 the trajectories corresponding to the flow field are shown. These show the trajectories of the droplets which will collide with the airfoil section. The two outer trajectories are also displayed, showing the first droplets that will not hit the propeller blade. In figure 5.2(d) there is a strange sudden angle in this outer trajectory. But as the droplet on this trajectory line do not influence any of the icing results it is left in.
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Three-Dimensional Analytical Model for an Axial-Field Magnetic Coupling

Three-Dimensional Analytical Model for an Axial-Field Magnetic Coupling

Abstract—In this paper, we propose an analytical method for modeling a permanent magnets axial field magnetic coupling. The three-dimensional model takes into account the radial fringing effects of the coupler. The analytical solution requires resolving the Laplace equation in low permeability subdomains. The magnetic field calculation allows the determination of global quantities like axial force and torque. 3D finite element computations as well as measurements validate the proposed model.

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Three-dimensional Simulation of the Field Patterns Generated by an Integrated Antenna

Three-dimensional Simulation of the Field Patterns Generated by an Integrated Antenna

Abstract— Simulating the electromagnetic field pat- terns generated by integrated antennas used in mobile phones, for example, is fundamental to understand- ing their transmission characteristics and thereby en- gineering designs that optimise the directional prop- erties of electromagnetic propagation. Modern inte- grated antennas have complex three-dimensional ge- ometry designed to optimise their performance in terms of their multi-band and multi-modal attributes. This geometry, coupled with their close proximity to other component of the device (such as the bat- tery and Printed Circuit Board, for example) pro- duce complex field patterns due to the scattering of the electric (and magnetic) field within a spatial do- main that is the same order of scale as the wavelength. Simulating this interaction therefore requires models that are generalised and not specific to an idealised antenna geometry. In this paper we present a three- dimensional model for simulating the interaction of an electromagnetic field generated by antennas whose geometry is arbitrary with complex dielectric compo- nents in the near-field, in particular, the Fresnel zone. The resulting field pattern is then taken to be a sec- ondary source, whose far-field intensity map is com- puted by application of a Fourier transform. The ma- terial properties of the dielectric are taken to include variations in the relative permittivity and conductiv- ity which are assumed to be isotropic. The evaluation of the scattered electromagnetic field is undertaken using a new approach based on a free space Green’s function to the Poisson equation whose properties are compared to the conventional Green’s function solu- tion to the inhomogeneous Helmholtz equation. Some example simulations are provided to illustrate the ap- proach used which include fractal antennas based on self-similar patterns.
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Utility of a three-dimensional wound measurement device in pressure ulcers

Utility of a three-dimensional wound measurement device in pressure ulcers

the reflection of infrared radiation. Therefore, the inaccurate measurement of the maximal depth may be owing to the inability of the device to precisely detect the wound edge because of the mortar-shaped wound of the second patient. Moreover, another possible reason was that the device failed to detect the deepest point of the PUs, which resulted in an underestimation of the maximal depth. According to the results of the third patient, the correlation coefficients were low to moderate. The vague wound edge of the third patient may have rendered the measurement results inaccurate. This may mean that there are certain wound characteristics that are unsuitable for measurement with this device.
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Symmetries in Three Dimensional Superconformal Quantum Field Theories

Symmetries in Three Dimensional Superconformal Quantum Field Theories

In this chapter we describe a method which enables one to study hidden, or accidental, continuous symmetries in strongly coupled superconformal field theories in three space-time dimensions. The existence of such hidden symmetries has been conjectured for many three- dimensional theories. We apply our method to two models. The first one is the recently proposed ABJM model [11] which has gauge group U (N ) × U (N ), an integral parameter k (the Chern-Simons level), and a manifest N = 6 supersymmetry. It is believed to have hidden N = 8 superconformal symmetry for k = 1, 2 [11]. The second model is the infrared limit of N = 4 d = 3 super Yang-Mills theory with an adjoint and a fundamental hypermultiplets. It is believed to be dual to the ABJM model with k = 1, as well as to the infrared limit of N = 8 super-Yang-Mills theory with gauge group U(N ), and consequently also must have hidden N = 8 superconformal symmetry. In this chapter we demonstrate the existence of supersymmetry enhancement in all three models. We also provide some evidence in favor of the duality with N = 8 super-Yang-Mills.
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Review Paper Ultrasonic Insight into Substituted Thiazoles and its Biological Activity

Review Paper Ultrasonic Insight into Substituted Thiazoles and its Biological Activity

has explain ultrasound has been utilize to asses a wide synthetically useful organic reaction and also used in therapeutic and diagnostic application viz. medical ultra sonography and teeth cleaning. Use of ultrasound makes it possible to carry out homogeneous and heterogeneous reaction of various types in liquid media and also in solid- liquid system 49 . iii. Javad Safaei Ghomi et.al. gave the advantage of ultrasound in chemical reactions such as shorter times, higher yields and milder condition could be useful for industrial application in the pharmaceutical or fine chemical industry 50 . iv. In recent year the ultrasonic velocity of liquids is fundamentally related to the binding forces between atoms and molecules and has been successfully employed in understanding the nature of molecular interactions in pure liquids, binary and ternary liquids mixtures 51 . v. The use of ultrasonic was proved to be useful probe for generating more information on many areas. The ultrasonic measurements have application in chemical and food processing, material testing under water ranging and cleaning. An ultrasonic vibrations is commonly employed in mechanical machinery material 52 . it is also applicable in preparation of colloids or emulsions in the pregeneration of seeds, for imaging of biological tissues 53 . Activation energy of metabolic process 54 . Formation and destruction of azeotropes in petrochemical industries and in non-destructive testing (NDT) 55 . Ultrasonic study of binary or ternary liquid-liquid mixtures are very important part of thermodynamics, acoustic and transport properties of system containing biologically important substituted thiazoles.
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Quantitative flow analysis around aquatic animals using laser sheet particle image velocimetry

Quantitative flow analysis around aquatic animals using laser sheet particle image velocimetry

Methods for recording and processing of reliable velocity vector diagrams have recently been developed in fluid mechanics (e.g. Adrian, 1991; Lourenço, 1991; Willert and Gharib, 1991; Hinsch, 1993). The flow, seeded with appropriate particles, is illuminated with a thin light sheet, often parallel to the main stream, and particle images on at least two successive moments are recorded photographically or on video tape. The images are enhanced if necessary, and velocity information is extracted from the images by tracking single particles (low seeding density) or by finding auto- or cross- correlations between sub-images (interrogation areas) using direct or indirect (using Fast Fourier Transforms) convolution filtering. Finally, the vectors are arranged in a regular grid resulting in a two-dimensional velocity vector diagram of the flow field. Prior to interpolating gaps in the flow field diagrams, the vector data should be validated (Raffel et al. 1992). Interpolation is best done using a spline interpolation procedure (Spedding and Rignot, 1993). Finally, velocity gradient parameters can be derived.
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Particle Velocity Sensor and Its Application in Near Field Noise Scanning Measurement

Particle Velocity Sensor and Its Application in Near Field Noise Scanning Measurement

Dr. H.-E. de Bree et al . of Twente University firstly proposed a μ-flown sensor, also known as particle velocity sensor (PVS), which realize direct measurement of acoustic particle velocity [4] [5]. Later, Dr. Bree and Microflown Technologies developed a series of products based on μ-flown sensor [6] [7]. The PVS has a directional, figure of eight, response. This directivity effect is independent of frequency, which makes the PVS extremely suitable to measure in real operating situations with background noise and reflections. Moreover, its operating fre- quency covers the whole frequency band and has a wider frequency response range. The PVS is Micro Electronic-Mechanical System (MEMS) device and can be up to the size of mm. Therefore, PVS is well suited for near-field noise mea- surement, especially in reverberation environment.
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Visualization tool for three dimensional plasma velocity distributions (ISEE 3D) as a plug in for SPEDAS

Visualization tool for three dimensional plasma velocity distributions (ISEE 3D) as a plug in for SPEDAS

the view of 2D slices of the distributions and contours on the slice(s) for further analysis. The tool also displays, in the same window, important information about space plasma, such as the direction of the magnetic field and velocity vectors. The transformation between spacecraft and magnetic field coordinate systems is implemented in the tool. We plan to extend the tool to plasma data from the  Arase (ERG) mission  (Miyoshi et  al. 2012; Miyoshi et al. this issue) and the Van Allen Probes mission (Mauk et  al. 2012) after replacing or adding the data loading plug-ins (i.e., an alternative of spd_dist_to_hash.pro for MMS data), and we expect that the tools can be also used for other satellite missions.
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MHD Three Dimensional Flow of a Williamson Fluid over a Stretching Sheet with Velocity Slip

MHD Three Dimensional Flow of a Williamson Fluid over a Stretching Sheet with Velocity Slip

ABSTRACT: An analysis has been carried out for the three dimensional flow of a Williomson fluid in the presence of porous medium and velocity slip. Suitable similarity transformations are employed to reduce the governing partial differential equations into coupled nonlinear ordinary differential equations. These non linear ordinary differential are then solved numerically by using the Runge-Kutta-Fehlberg method. Obtained solutions are compared with previous results in a limiting sense from the literature, demonstrating an excellent agreement. The physical features of non- dimensional Williamson parameter, magnetic field parameter, stretching ratio parameter, velocity slip parameter and porosity parameter have been discussed by plotting the graphs of velocities in both directions.
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Verification of micro scale photogrammetry for smooth three dimensional object measurement

Verification of micro scale photogrammetry for smooth three dimensional object measurement

Photogrammetry is a passive triangulation technique based on the matching of points between many images of an object [1]. Through the matching of points over the surface of an object, photogrammetry is able to triangulate a point cloud for which geometric information about the object may be extracted. The accuracy and working range of photogrammetry depend on many factors, the most important of which are the camera parameters and reconstruction algorithms. Given the significant advancements of both imaging and computation technologies over the last few decades, photogrammetry has been able to extend its range down to sub-millimetre scales. Commercial systems, such as the geodetic V-STARS range, are already able to measure objects 1 m to 10 m in size with uncertainties of 5 µm + 5µm/m [2]. In particular, more recent research has shown that photogrammetry has the potential to provide three-dimensional (3D) form measurements to standard uncertainties of less than 10 µm [3–9]. There are other applications of photogrammetry able to produce even lower uncertainties, such as reconstructions based on scanning electron microscope (SEM) images [10]. Although SEM based photogrammetry is able to produce high magnification images, it will not be covered by the scope of this paper due to other issues such as cost, field of view and surface pre-processing. Given the relatively low uncertainties of recent results, photogrammetry is promising for micro-scale coordinate metrology.
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Measurement of cerebral blood volume with subtraction three dimensional functional CT

Measurement of cerebral blood volume with subtraction three dimensional functional CT

The blood-brain barrier, if intact, prevents ex- travasation of contrast material into the ex- travascular space, and thereby makes feasible the use of current, clinically approved iodine- based contrast agents for subtraction 3-D func- tional CT cerebral studies. However, in some pathologic situations, the blood-brain barrier may break down, allowing some contrast agent particles to pass into the extravascular space. Thus, the measurement of CBV becomes sub- ject to error; generally, an overestimation of CBV occurs. Spiral CT technology, however, is able to acquire the data with considerable speed (a 3-D data acquisition of the whole brain re- quires about 30 seconds), so that the time for extravasation is minimal and any error caused by it is thus negligible. Earlier studies (CT and radionuclide brain scanning) have shown that impaired perfusion in the ischemic area delays the time at which contrast agent extravasation can be detected (24). For instance, Gado et al (24) have postulated that the lack of observable CT enhancement in brain infarction was the re- sult of impaired perfusion and slow delivery of the contrast material in CT studies that were acquired after 4 minutes of contrast infusion.
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Digital holografic interferometry used for identification of 2D temperature field

Digital holografic interferometry used for identification of 2D temperature field

Noncontact measuring methods are very suitable for temperature field distribution measurement. One of the biggest benefits of holographic interferometry over standard interferometry is its differential character. This in general means that imperfections in the beam paths do not influence the shape of obtained phase field. Digital holographic interferometry which has its own experimental difficulties is very attractive due to its direct retrieval of the interference phase after computer based evaluation of hologram [1]. Interference phase modulo 2π is obtained by subtracting two phase fields reconstructed from holograms captured in two different time instants. One is usually the reference and the second is the record after change of the measured property. In a measurement of a 2D temperature field distribution (synthetic jet’s properties as it impinges on the heated surface), DHI enables us to measure the temperature distribution in the area of interest. For measurement of transparent “phase objects”, a Mach-Zehnder holographic interferometric setup is commonly used. In this type of measurement the phase change is induced by the measured phenomenon is small, thus the sensitivity of the commonly applied interferometer is not sufficient.
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Measurement of three-dimensional stress field of RP model having a notch by using digital holography

Measurement of three-dimensional stress field of RP model having a notch by using digital holography

consider observation volume as grid points 30 × 11 × 17 in x, y, z directions respectively. Central di ff erences are used at each grid points. In (a) of Fig. 6, vector field in RP model is measured by Holographic PTV as an experimental fluid mechanics. It is found that vectors near a V-notch are resolved. A large stress gradient near a V-notch is also visualized as shown in (b) and (c) of Fig. 6. However, the proposed method indirectly measures three-dimensional stress field. The model can be not only measured repeatedly under several conditions but also can be measured with dynamic load.
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