2D flow visualization by laser holograph interferometery in shock tube and some applications in Computational Flow Imaging are presented.

Multiphase pipeline flow is very important to oil, gas and process industry. This is a class of problems where comprehensive simulations, although desirable on physical grounds, are not practical due to the large aspect ratio between the pipe length and diameter. In order to enhance the understanding of the pipeline flow, as well as to validate and identify the critical aspects of these models, intensive experimental data are needed. This will define how these models can be improved.

Improvements on the Global Rainbow Thermometry (GRT) technique are being presented. The GRT technique allows us to study the physical properties of liquid-in-liquid and liquid-in-air dispersions. In this paper the influence of droplet non-sphericity on the size and temperature measurements of liquid droplets suspended in a liquid or a gaseous bulk will be analyzed. A new theoretical model that takes into account the effect of the non-spherical droplets on the GRT signal will be proposed and a data inversion algorithm is described. It allows to automatically find the optimized parameters of the simulation of experimental Global Rainbow patterns. Expeirmental validation of the rainbow thermometry technique is performed, measuring the droplet size and temperature by means of alternative techniques to compare with the present method. For this purpose, an original experiment has been designed.

Digital speckle correlation method (DSCM) is based on the correlation-matching search algorithm, in which the correlation coefficient is used as a criterion for matching of two speckle patterns. The properties of the correlation coefficient affect the accuracy and the searching speed of DSCM. As many as ten different definitions of the correlation coefficient can be found in literatures but almost no comparison works are reported. In this paper, the different coefficient equations are compared and the properties of all these definitions are concluded. The comparison results may help to improve the development and application of DSCM in future. Some new correlation coefficients with better properties are then defined on the basis of the comparison.

Cell growth experiments are used to determine the effects that various environmental factors have on the development and life cycles of cells. For current earth-based testing, the experiments are conducted in Erlenmeyer flasks on orbital shaker tables. This method has been used for several decades and serves as teh baseline-testing configuration. In the future, cell growth experiments will be conducted on the International Space Station (ISS), which will permit long duration testing of the effects of gravity on the development and life cycle of cells. Particle Image Velocimetry (PIV) has been used to measure the 3D velocity field within the flasks. The high-resolution PIV data have been used to calcluate accelerations and shear stresses that the cells typically encounter during testing. The PIV data will be used to verify that the fluid environment during testing on the ISS is comparable to that encountered during earth-based testing.

This paper describes a device for 3D profile measurement systems, which are based on grating projection method using phase shifting technique for fringe analysis. As a key component of these systems, we propose to apply a liquid crystal (LC) grating instead of a conventional ruled grating, which has difficulty in speedy and accurate shifting of the projected pattern. This LC grating consists of 960 lines of stripe pattern on the substrate of 60×40 mm² in size and has such features as 8 bits of gray levels in dynamic range in use of mono-chromatic applications. A sinusoidal pattern as well as a binary pattern in realized by combining pulse width modulation control and frame ratio control technqiue. In addition, the period of the pattern is arbitrarily controlled and shifting of the projected pattern is also electrically realized. We demonstrate a few examples measured by the system which uses this LC grating inside.

A digital in-line holography recording system was used in the holography particle image velocimetry for a 3D flow measurement that are made up of the new full field fluid mechanics experimental technique--DHPIV. In this experiment, the traditional holography film was replaced by a CCD chip that record the interference stripe directly without the darkroom processing, and the virtual image slices in different position were reconstructed by compuation using Fresnel-Kirchhoff integral from the digital image. Also, complex field signal filter was applied in image reconstruction to achieve the thin depth of image field that has strong effecting with the vertical velocity component resolution. Using the frame-straddle CCD techniques, the 3D velocity was computed by 3D cross-correlation through space interrogation block matching through the reconstructed image slices with digital complex field signal filter. Then the 3D velocity, vortex, iso-surface details and the time evolution movie in a 3D flow field were displayed by numerical computation and experimental measurement using this DHPIV method.

Convective motion in fluid dynamics and heat transfer is the most important phenomenon to be understood since it can greatly influence the performances of fluid and heat transfer systems in various manners. With the advances of modern technologies, new diagnostics for mapping 3D convective flow is veyr necessary for fundamentals of flow physics. Especially, modern computational modeling has been greatly advanced to demand 3D convective-flow diagnostics in order to verify and tune the methodologies and approaches. Conventional velocimetry is either pointwise or 2D. If available, 3D gross-field velocimetry can allow us unprecedented physical insight as well as the needed data for validation of numerical codes and understanding of funamental flow physics. In an effort to meet the need of 3D flow diagnostics, we have developed stereoscopic tracking velocimetry (STV). STV is based on the simultaneous stereoscopic monitoring of numerous particles dispersed in a carrier fluid. It can thus provide time-sequence velocity maps of an entire flow field. Here we briefly present the methodology of STV and its experimental measurement results of 3D flow fields including the traditional flow involving a free jet and the directional solidification for material processing.

In this paper, several techniques for fluid measurement, such as Optical Interferometry and Particle Image Velocimetry (PIV) etc. are introduced. And their applications on the fluid physics experiment of simulation microgravity on the ground in the national microgravity laboratory are presented. To reduce the gravitational effect on the ground, the character sizes reserached objects are generally very little. The measuring techniques of fluid mechanics have to be combined with micrology to carry out the measurement of little size.

The experiments are run in an inhomogeneous turbulent shearless layer generated in a wind tunnel with two different meshes. A PIV system synchronized simultaneously with a Mie scattering diffusion concentration system is used in order to obtain the velocity and concentration fields at the same instant. We present here some statistical results for both velocity and concentration and also the mean flux. Filtering and subgrid scale modeling are applied to experimental velocity and concentration field in order to check the effect of the length of filter and the accuracy of subgrid model of LES.

Parallel lines viewed in a picture taken with a camera appear to meet at a vanishing point. Three groups of parallel lines which are perpendicular each to other appear three vanishing-points in a perspective picture. This paper proposed an algorithm by which real 3D position of the viewpoint and imaging plane of the picture and the scale of the picture are determined based on positions of the three vanishing-points. In this paper the principle of perspective geometry, visual geometry, was also discussed, especially the vanishing-point theorem. Meanwhile, this paper also proposed a method by which real 3D positions of the objects are determined with a two-viewpoint imaging system.

A micro PIV system has been developed as a new diagnostic tool for micro scale flow and applied to the measurement of microchannel flow. The micro PIV system employs the incident-light fluorescent microscope system and utilizes high-power pulsed Nd:YAG lasers, a high-resolution CCD camera and 1 μm diameter fluorescent tracer particles. The velocity distributions of pressure-driven flow and pressure- and electrokinetically-driven flow in a microchannel were measured using the micro PIV system and the visualization of flow fields in a microchannel was demonstrated.

The paper studies three-component PIV techniques used in 3D flow field measurement. Lateral stereovision was employed to locate the spatial position of particles and a progressive approach was used to measure the position accurately. A new epipolar constraint algorithm for the corresponding match was put forward. The algorithm can reduce the search area under perspective distortion. Fuzzy pattern recognition was introduced to PIV adjacent frame matching and fuzzy clustering was employed to implement the moving analysis of local particles in double exposure PIV images. Finally, a simulated experiment of 3D PIV analysis was completed by the techniques mentioned above.

There are two basic configurations of stereoscopic particle image velocimetry (SPIV) systems: translation system and angular-displacement system. Theoretical and experimental error anaysis of SPIV is summarized. The results of theoretical error analysis indicate that the angular-displacement SPIV system with the Scheimpflug condition can provide up to 40% higher out-of-plane accuracy than the translation systems. Experimental error analysis of SPIV is to directly estimate the uncertainties from actual SPIV recordings after accurate automatic registration provided the imaged object's characteristics are known. Moreover, a liquid prism ensures that two camera continue to enjoy an orthogonal orientation with respect to the liquid-air interface.

In this paper an experiment on measurements of the wake of Goldfish carassius auratus swimming unrestricted was conducted in a water tunnel. Color liquid was used to visualize the wake of the fish and PIV was used to measure velocity field of the wake. Results show that there is reverse Karman vortex street in symmetrical plane of the fish's wake and the Strouhal frequency of the fish is about 0.35 udner the different experimental conditions. The distribution of velocity and vorticity in the wake of Goldfish was measured by PIV and formation of reverse Karman vortex street in the wake was studied in a model experiment.

SPIV was applied to a large-scale low-speed compressor facility with the configuration of the two CCD cameras placed on each side of the light sheet, so the periscope-type probe containing light sheet forming optics is not needed in the measurement, and the instantaneous velocity and vorticity distributions in several cross sections were successfully measured in the tip region of the compressor rotor at the design and near stall conditions. The results show SPIV would be a very attractive and powerful diagnostic tool for the study of complex turbomachinery flow. Some problems encountered in the measurement are also discussed.

An experimental investigation of Benard-Marangoni convection has been performed in double immiscible liquid layers of rectangular configuration. The two kinds of liquid are 10cst silicon oil and FC-70 respectively. The velocity fields in the vertical cross-section are obtained by PIV. Flow patterns and/or temperature distributions on the horizontal interface are displaced by using thermal color liquid crystal (TLC), and the velocity distributions on the interface were also obtained with the help of the serial particle image of TCL. The evolution processes of convection are observed in the differential thickness ratio of two liquid layers, and the convection styles are discussed.

The velocity fields of oscillatory convection have been measured using the techniques of Particle Image Velocimetry (PIV) in a liquid bridge of half floating zone with small typical scales of a few millimeters for emphasizing the thermocapillary effect in comparison with the effect of buoyancy. The flow patterns of the oscillatory flow have been studied experimentally in a liquid bridge. The flow patterns in the liquid bridge are classifeid with mode numbers according to oscillatory flow characteristics. Results of the experiment show that the mode depends on the aspect ratio as well as the volume ratio of the liquid bridge. The experimental results are helpful for studying the structure of flow at the onset of oscillatory thermocapillary convection in a liquid bridge.

The flow fields behind elliptic cylinders with different aspect ratios adjacent to a free surface were investigated experimentally in a circulating water channel. The elliptic cylinders tested in this study have same cross section area. For each elliptic cylinder, the experiments were carried out under different conditions by varying the submergence depth of the cylinder beneath the free surface. The flow fields were measured using a single-frame double-exposure PIV system. For each experimental condition, 350 instantaneous velocity fields were captured and ensemble-averaged to obtain the mean flow field information and spatial distribution of turbulent statistics. The near-wakes can be basically classified into three typical patterns, which are formation of Coanda effect, generation of substantial jet-like flow, and attachment of jet flow to the free surface. The general flow structures behind the elliptic cylinder are similar to previous results for a circular submerged near to a free surface. However, the wake width and the angle of downward deflection of the shear layer developed from the lower surface of the elliptic cylinder are smaller than those for the circular cylinder. These trends are enhance with increasing of the cylinder aspect ratios.

Electrospray is a process that relies on the electrostatic force to break the liquid into fine charged droplets. Electrospray ha several features by contrast with other atomization techniques. Since the size distribution of the droplets in electrospray is monodispersity when the spray operates under the Taylor-cone mode, and it is well controllable, the electrospray is applied in many fields such as material process, mass spectrometry technique, drag delivery, and ink jet print etc. In this paper, Dantex Flowmap 1500 PIV system with double-pulse Nd:YAG laser was used to measure the whole instantaneous velocity field of the electrospray droplets. The measuring results show that many effects, such as the applied voltage, flow rate, and temperature, will influence on the velocity distribution of the drops. The velocity distribution of the electrospray dorps is axisymmetric. The highly applied voltage will lead the droplets to accelerate during falling.

The detailed near-wake flow behind the Edge Blowing Mixture Curtain flameholder and the V-gutter flameholder were investigated by using 2D cross-correlation on-line PIV in a low speed wind tunnel. Experiments were conducted at the main flow velocity of 10m/s and 20m/s, the jet velocity of 10m/s and 20m/s respectively. Results show that near-wake flow structure of both flameholders is governed mainly by large-scale vortices in the form of vortex street, and the jet increase the size of the vortices. But symmetrical large-scale vortices appear when the momentum ratio of the jet to the main flow is high, which is disadvantage to combustion. Based on the research on the instantaneous flow, the instantaneous viewpoint of the flame stability mechanism was brought forwad. Important effect of alternate formation and shedding of vortices on the flame stability was discussed. All of these offer important theoretic basis for further studying combustion performance of the novel flameholder.

This paper presents an experimental study of the influence of 2D leading-edge geometry on transition and performance. The measurements were conducted on a special large-scale experimental facility, the pressure distribution and flow field were measured. The test model used in this study consists of circular leading edge and elliptic leading edge. Results are presented for a range of incidence. The measurement result indicated that the leading edge shape has a large influence on flow details, separation and transition as well as the boundary layer properties after reattached point.

A towing PIV system in large towing tank at China Ship Scientific Research Center is presented, also its application in the investigation on the effect on flow structure of juncture forms of stern appendage with submarine-like main-body. The coefficients of non-uniformity of the nominal wake for five juncture forms are assessed and compared.

This paper describes a study of the conditions inside a turbo-drill turbine cascade of high circulating flow coefficients using the PIV method. Measurements of velocity vector fields and derived vorticity were obtained and their characteristics determined. The fluid drill mechanical energy transfer, overall energy-losses and flow features responsible for these effects were investigated.

An agitator rig is built to observe the unsteady characteristics of the large vortex produced by the rotor-stator interaction in impeller machinery. Using a PIV, a speeder and an encoder, the instantaneous velocity measurement is finished at a group of rotating speeds and phase angles, respectively. The ensemble averaged velocity, vortex streamline and turbulent intensity are obtained from PIV data. The results show that the distribution of the instantaneous parameters has no periodicity. The ensemble-averaged vortex is mainly located in the neighborhood of the static vanes, and the phase angle has little influence on it. The turbulent intensity has similar characters with the vortex.

We present here a pretty simple method for matching the indices of refraction between a solid and a liquid, which is needed for flow visualization inside porous media. With this technique, a matched medium, consisting of Duran glass beads and a mixture of Dow Corning 550 and Dow Corning 556 is made. Experiments are conducted in an open channel with a porous bed and overlying fluid to investigate fluid dynamics in the interface region of fluid and porous. Using Particle Image Velocimetry, flow fields both in the fluid region and within porous region are obtained.

The laser diagnostic and visualization technology provides proper methods to understand the turbulence flow and the interaction between flow field and electricity field. In this paper, PIV is used to make instantaneous velocity measurements over a 120mm by 150mm area in the spray and detailed properties of electrospray are obtained. Small size particles are dispersed in spray space in advance and the vortices on the edge of spray are apparent in the measurement results. The comparison of velocity, turbulence momentum and vorticity between charge spray and conventional spray is presented.

Fuzzified neural network based on fuzzy number operations may be one of powerful fuzzified neural networks. We introduced a fuzzified neural network basd on fuzzy number operations which approximates targets by choosing the shapes of the weights and the biases and calculating the left, mean and right values of each weight or bias. However, as we have pointed out, the learning algorithm is a little time-consuming. We propose a parallel learning algorithm for the fuzzified neural network in this paper. The parallel learning algorithm works well for the fuzzified neural network.

The fluid flow associated with micro and meso scale devices is currently of interest. Experiments were performed to study the fluid flow in meso-scale channels. A straight flow tube was fabricated with 1.0×4.0mm² in rectangular cross section and 200mm in length, which was made of quartz for flow visualization and PIV measurements. Reynolds numbers were ranged from 311 to over 3105. The corresponding pressure drop was from 0.65KPa to over 16.58KPa between the inlet and outlet of the tube. The micro PIV was developed to measure the velocity distribution in the tube. A set of microscope object lens was mounted ahead of CCD camera to obtain optimzed optical magnification on the CCD chip. The velocity distributions near the outlet of the tube were measured to obtain full-developed flow. A CW laser beam was focused directly on the test section by a cylinder lens to form a small light sheet. Thus, high power density of light was formed on the view region. It is very important to the experiment while the velocity of the flow reaches to a few meters per second within millimeter scale. In this case, it is necessary to reduce exposure time to microseconds for PIV measurements. In the present paper, the experimental results are compared with the classical theories.

The phenomena of Portevin-Le CHaltelier (PLC) band propagation and its pulsation were investigated by using dynamic digital speckle pattern interferometry (DSPI). Pulsation of fringe density in the inside of the slip band accompanying with the serrations of load curve was observed. When the load falls in the serrations, the slip deformation happens just like an avalanche, and the specimen takes a shrinkage deformation in the outside of the slip band to compensate the elongation deformation in slip band, even for a tensile test. The maximum elongation in the slip band causing by the avalanchine slip is about 7.6 μm.

The measurement of in-plane surface strain is very important in structural material research. The traditional strain measurement techniques, however, have their clear constaint and inconveniency in terms of both sensor system arrangement and data analysis. This paper presents the development of a novel technique for estimating the local surface strain over a region. The key element of the technique is a high accurate image displacement detection algorithm. This algorithm is based on the Optical Flow concept and implemented in a multi-scale analysis scheme. This technique is aiming at covering large viewing area and detecting small deformation components on the top of large translation with high accuracy. A numerical differentiation procedure is also discussed to derive strain field from the displacement field. The test procedure of this technique is also presented in this paper. The test procedure consists of absolute translation calibration and strain calibration against strain-gauge measurement. The experimental results show a very good agreement between the proposed technique and the well-established traditional measurement.

Binary speckle correlation evaluated by computer simulations. Accuracy, sensitivity, computing speed and the image compression ratio are considered.

The signal to noise ratio of speckle pattern is unity, so it is difficult ot extract signal from a single speckle pattern. We have presentd a method of smoothing speckle fringe patterns is proposed, basing on the upper method. For a series of speckle fringe patterns, the location of the fringe is changing continually. According to the feature, the smoothing is implemented with great efficiency and speed.

A new method combining temporal phase analysis with dynamic digital speckle pattern interferometry is proposed to study Portevin-Le Chatelier effect quantitatively. The principle bases on that the phase difference of interference speckle patterns is a time-dependent function related to the object deformation. The interference speckle patterns of specimen are recorded with high sampling rate while PLC effect occurs, and the 2D displacement map of PLC band and its width are obtained by analyzing the displacement of specimen with proposed method.

A new full-field optical technique is developed to study surface deformation of solids. This method combines the measurement by grid method and the digital image processing. An optical information processing system and a digital image processing system of computer are used in this method. At the output plane we receive the pattern of grating lines taht can be used for the analysis of deformation of the specimen on which we have produced the phase grating. At last we show the application of this technique in the investigation of elastic-plastic fracture.

A technique for measuring in-place displacement under impact loading using digital speckle pattern interferometry (DSPI) with combining the digital subtraction and add mode is presented. A new technique of the add mode filtering is used. To grab the digital speckle of field produced by a pulse laser, an instantaneous digital image grabbing system is proposed. Thus the dynamic digital speckle image can be recorded and stored in a digital frame store. As an example, the displacement field of a semi-infinite model udner impact loading is measured.

In this paper, the digital speckle correlation method (DSCM) is selected as the experimental means to calculate the J integral of foil material. The deformation fields in the crack tip region are measured and their contour maps are shown. The formula using deformed field to calculate J integral is derived. Through calculating J integral of foil material by the DSCM, it is shown that this experimental method is a useful test technique in studying the mechanical behavior of film or foil materials.

In this paper, the technique of electronic sheraing speckle pattern interferometry with wide Audio-frequency driving vibration is used in non-destructive test of the multiply plywood structure. Test results show that we are able to evaluate promply the soundness of bonding of the plywood. In the process of test not only can we find any locations of defects from the synthesized intensity map very quickly, but also can obtain the shape, size and resonant frequency of every interior defect of the multiply plywood accurately.

The key problem to enhance the precision of displacements measurement with image correlation is to make the most of correlation behavior of speckle images. In fact, the artificial random speckles or natural texture, especially the microcosmic texture, on the object's surface have fractal characteristics, and the digital images of these patterns are also fractals. It is found that there is correlation between the fractal characteristics in un-deformed and deformed states of the images. Based on this fact a method called fractal correlation method, can be used to measure displacements. In this paper, the fractal correlation method was used to measure the displacement field on a crack tip of a metal specimen. The microcosmic natural texture on specimen's surface was taken as images, and the area was 1.397×1.397mm. By correlation operation with the fractal correlation method, curves of displacement around the tip can be obtained. The position of crack tip can be clearly distinguished from the displacement curves. The relationship of COD and distance behind the tip is linear. This agrees with the theory of fracture mechanics. The results also show that the plastic field does not distribute in uniform.

In this paper, an experiment is executed to analyze the displacement distribution of 56-ply composite laminates under three-point bending. In the experiment, the displacement fields on the two free edges of the laminated composite are measured by using the moire interferometry method and natural micro-image processing technique based on wavelet transform at the same time. In the first part of this study, a two-beam traditional moire interferometry experiment has been carried out. And in the second part, we present a new image processing method, which combines the theory of correlation and wavelet transform technique.

In this paper a Laser Moire deflectometry applicable for mini/micro-scale flow visualization is proposed. Based on the moire effect, the displacements of moire fringes can be used to calculate the deflection angle of laser beam, which is induced by the variation of refractive index in thermal flow fluid. Thus, density and temperature distribution of flow fluid can be obtained. The physical and mathematical model of the laser moire deflectometry is presented in detail. A digital image processing method of moire fringes by using Fourier transform is discused. The researches show that laser moire deflectometry can meet needs of mini/micro-scale temperature field for natural convection of a heated thin wire is experimentally demonstrated by means of the laser miore deflectometry.

The structure of the vortical flow behind a symmetrical airfoil of finite aspect ratio undergoing combinations of heave and pitch motions is investigated using qualitative dye flow visualization. The results are contrasted with flow visualizations obtained using electrolytic precipitation. The effect of changing the pitch amplitude is observed from the plan from view and wingtip view of the airfoil. With a Strouhal number of 0.35, Reyholds number based on airfoil chord of 164 and a phase angle of 90o, the maximum pitch amplitude is varied from 0° to 20°. The geometry of the downstream vortical flow is observed to change suggesting that the induced velocity from interacting structures decreases at lower pitch amplitudes. The rate of dynamic stall development may also be affected by variations in pitch amplitude since it appears that the timing of leading edge separation is affected. The flow field of an airfoil flapping periodically about a fixed axis appears to be influenced by the amplitude of pitching oscillations. At the tested Strouhal numbers the vortex formations appear to be primarily dependent on airfoil oscillation rather than heave translation. Furthermore, the results suggest that the wake structures originating from the dynamic stall process are important for the analysis of these complex flows. While the results from the two flow visualization techniques are similar, the dye flow visualization images provide greater qualitative insight. Inherently, precipitative techniques such as the one used here could provide good flow visualizations since the smoke/particles leave the surface of the airfoil, but the setup is found to be very sensitive to potential changes. The ion content in the electrolytic material was also found to play a role. Furthermore, the high ablation rate of the technique presented some practical problems.

The light sheet technique provides a unique method of visualization for off-body flow fields at subsonic through supersonic speeds. But conventional mirror tansmission laser systems have some shortcomings: The harsh environments of high speed wind tunnels often cause the misalignment of the optical components and the contamination of the mirror surfaces. The exposed laser beam is dangerous to the persons at the work sites. This paper presents an advanced optical-fiber-transmission laser sheet system, which provides a solution to the problems above and greatly improves the quality, safety and reliability of the light sheet. The emphasis is laid on the detailed composition of the new type visualization system. Some examples of its applications in transonic/supersonic wind tunnels are also given in this paper.

Full surface strain measurement requires the determination of two out-of-plane and four in-plane displacement gradient components of the surface strain tensor. Shearography is a full-field speckle interferometry technique with a sensitivity predominately to the out-of-plane displacenet gradient. Speckle pattern photography has the sensitivity to the in-plane displacement, and taking the derivative yields the in-plane dipslacment gradient. In this paper the two techniques are combined to yield a single-access multi-component surface strain measurement using shearography to measure the out-of-plane components and speckle pattern photography to measure the in-plane components. Results are presented of a multi-component surface strain measurement.

In this paper, an explosion, which starts at the center of a vortex, is considered. A shock tube was used to conduct the experiment. A vortex is generated when the shock wave propagates around a wing-shaped model. The explosion is triggered at the time when the vortex arrives at the position where the explosion wire is located. Holographic interferometery was used to visualize the vortex-explosion interaction. Both experimental and numerical results showed that a vortex, after disturbed by an explosion, is strongly deformed and smeared out, which suggets that vortex might be suppressed or even destroyed with an explosion. More careful works need to be carried out in the near future in order to get more detailed and quantitative information for both academic and application interests.

Wax-crystal morph is one of the prime inner factors that influence the rheological property of waxy crude at low temperature. The normal way to identify wax-crystals is comparing qualitatively the wax-crystals obtained from video-microscopy. The paper studies a quantitative characterization and classification of wax crystals of waxy crude oils. In this paper, a blocked 2D etropy threshold method was used to segment wax crystal images, and the grain size, shape characters of wax crystals and the continuous liquid phase characters are extracted through a statistic method. Finally, the fuzzy clustering method was employed to classify the wax crystal images.

In order to find a new method to compare the theory results with experiment results, it is necessary to develop the technique of computer simulating flow visual, which gets flow visual image from the computational flow field data. The computer simulation technique for flow visualization is the technique of CFI. CFI is succinctly defined as the art and science of generating digital images of theoretical fluid observations of real flow fields. It involves numerical value calculation, image processing, computer graph and other techniques. In this paper, we study four kinds of CFI technique. They are CFI-Schlieren, CFI-Shadowgraph, CFI-Interferometry and CFI-Color Schlieren. The algorithms of CFI-Color Schlieren and CFI-Interferometry are amply dissertated and some computational images are provided. Then we have accomplished the laser holographic interferometry experiments of shock wave diffracting double cubes model. We compare experimental interferograms with CFI images. The result verifies the validity of the theory. The comparisons of the computation with experiment are given in this paper. At the same time, we have developed the computer simulation software for flow visualization. The software provides a new approach to test and verify experiment and theory result. This paper also gives a description about the design method and function of the software. In the end, we also discuss the developing direction of the future.

Computational flow imaging (CFI) uses theoretical predictions of the interaction and transmission of optical waves through theoretical flowfield to generate digital pictures that simulate real observations, but the phase data produced by interferometric, Schlieren or shadow graph is the result of the integration of the refractive index or refractive index or refractive index gradient along the line-of-sight. The goal of this research is to develop a fast, efficeint ray casting method for integral calculation of computational flow imaging. We use a preprocessing procedure that the whole flow region is divided into new regular blocks in which the voxels are distributed by x and y coordinates to increase the processing speed. The algorithms are generally enough to handle non-convex, curvilinear or irregular grids and cells and grids constructed from multiple grids of CFD solutions.

A new moire interferometer, known as multifunction 3D function interferometry system is developed by authors, which combines the advantages of four-beam moire interferometer with the Twyman/Green interference system. The system can measure in-plane and out-of-plane deformation synchronously with high accuracy and high sensitivity. A compact phase shifter is used to improve the measurement sensitivity. The optical theory, components, key techniques, unique ability, and specifications of the system are described in detail in this paper. Some typical experiments using this system have been done and gained good results.

A combined system of four beams moire interferometer and incremental hole-driling machine was designed and applied for residual stress measurement. Two typical experiments were done using this system: non-uniform in-depth residual stress measurement of an ultrasonic shot-peening Aluminum plate; non-uniform in-plane residual stress measurement of an elastic-plastic Aluminum bent beam. Experiments results show good accordant with other measurement results and theory analysis results.

A new focused ion beam (FIB) miore method is proposed to measure the in-plane deformation of object in a micrometer scale. The FIB moire is generated by the interference bewteen a prepared specimen grating and FIB raster scan lines. The principle of the FIB moire is described. Several specimen gratings with 0.14 and 0.20 micron spacing are used to generate FIB miore patterns. The FIB moire method is successfully used to measure the residual deformation in a MEMS structure after removing the SiO₂ sacrificial layer with a 5000 lines/mm grating. The results demonstrate the feasibility of this method.

A new phase shifting SEM scanning moire method is proposed in this paper. The phase shifting technique is realized in four steps from 0 to 2 π by shifting electron beam in y-axis direction controlled by SEM system. It is successfully applied to measure the virtual strain of a MEMS structure with grating of 5000 lines/mm. The experiments prove the technique can be widely used in meso-deformation measurement, and also show the sensitivity of experiments is highly improved after phase shifting technique. It provides a new way for disposal of fringes patterns in sub-micro moire method.

This paper introduces how to in situ observe fracture behavior aroung a crack tip in ferroelectric ceramics under combined electromechancial loading by use of a moire interferometry technique. The deformation field induced by electric field and stress concentration near the crack tip in three-points bending experiments was measured. By analyzing the moire interferometry images it is found that under a constant mechanical load, an electical field has no effect on crack extension in the case that the directions of the poling, electric field and crack extension are perpendicular to each other. When the poling direction is parallel to the crack extension direction and perpendicular to the electric field, strain decreases faster than values predicted by the theoretical analysis as the distance away from the crack tip increases. In addition, as the electric field raises the strain near the crack tip increase, and the strain concentration phenomena becomes more significant.

In this paper, moire interferometry method is applied tostudy interfacial fracture behavior analysis of Porcelain-Fused-to-Metal restoration. The SIF with respect to the crack of four-point bending specimens are studied by moire interferometry. The Carrier technique is applied to get the phase and displacement of the interfacial crack. The SIF is attained by the method of this paper. The experimental result proves the moire interferometry method can be applied to the small specimen with the interfacial crack.

In the present paper, a method for measuring the shear-stress distribution over a solid surface in a fluid flow is studied with a use of shear-sensitive liquid crystal coating. The color response of the liquid crystal coating is calibrated against the various shear stress magnitudes and directions using an experimental test section of laminar channel flow. The measurement of shear stress distribution is carried out with a use of two color CCD cameras situated side by side. The color to shear stress transformation is conducted by the analysis with use of relative hue as a calibration variable, which is a function of shear stress magnitudes and directions. The usefulness of this technique was confirmed by the measurement of shear stress distribution around a circular cylinder with small span.

The most important procedure for improving accuracy of modeling in stereo-lithography is to clearly identify the relationship between the conditions of laser irradiation and the solidification of photo-curing resin for modeling. The parametric study concerning laser power, laser beam diameter, laser scan speed and properties of photo-curing resin was conducted in order to find those influence on the dimensional accuracy of the solidified resin.