A three-tube color TV camera simulating insect vision by means of the false-color method and sensitive at wavelengths of 300-650 nm (from UV to yellow) has been developed. In this camera, UV components are converted into red, while blue and green components are left in their original colors. The camera makes it possible to show with great color an insect's view of floral nectar guides and sexual differences in coloration in the cabbage white butterfly, colors of which are invisible to the naked human eye. Applications of this camera in many fields including education, environment and medicine can be expected.
The main object of this study is to present an experimental investigation of the relation between the deformation of flexible surface and hydrodynamical force acting on a circular cylinder in uniform flow. Thin rubber film is folded on a circular cylinder keeping a small gap where water is filled up. The cross-sectional form of the circular cylinder is visualized by applying a laser light sheet. A strong deformation caused the sharp fluctuation of brightness in image. Then classification of image and ridge tracing technique is applied to image analysis of shape determination. It is proved that amplitude of shape deformation isclosely related to the variation of hydrodynamical force.
Buccal mass is a distinctively spherical organ for feeding, and specific to cephalopods. Its movement in feeding has not been observed in vivo. It was successful that ultrasonography (Aloka SSD-500) could visualize buccal mass movement in Paroctopus dofleini. 5.0MHz, linear scannig was the best frequency to visualize the body of this species. The buccal mass rotated 8.6 times per minute, angles of rotation were in the range between 50 and 65 degrees in sagittal section.
Experiments and numeritorical calculations have been carried out to elucidate the gas exchange in pulsating flow through a two-dimensional duct with sudden expansion, which simulates the nose. The pulsating flow was visualized by the tobacco-smoke. method and the smoke wire method, and the streaming was studied numerically by the time-line method. the results show that the streaming occurs around the open end of the duct to bring about a forced gas exchange.
This is an experimental study visualizing the interaction of air bubbles with underwater shock waves and is related to the investigation of tissue damage induced during extracorporeal shockwave lithotripsy treatment. Two optical visualization techniques, such as holographic interferometry and conventional photography were intensively used. The result of visualization revealed that various collapse patterns exist depending on properties of surrounding materials and the tissue damage could be generated mainly due to liquid jets formed inside the bubbles.
There have been variety of riverside tree planting in Japan since ancient times. In this study, the authors try to establish effective method of planting from the view of landscaping. Visual simulation is used to obtain the visual image of tree planting. The technique of photo-montaga is applied in this visual simulation system by use of personal-computer. This technique is available to make accurate presentation and save a lot of troublesome. In our case study, the interval on the row of trees was evaluated by the visual simulation system. The authors obtained desirable image of riverside tree-planting by sketch questionnaires using the visual simulation reproduction system.
Recently in Japan, many bridges have been built with deliberate consideration on landscape and aesthetic aspects. There are several measures for landscape prediction but no effective tool has been developed for landscape design of a bridge form. The authors have been developing a prototype of comprehensive computer aided design(CAD) system for visual design of a bridge form. In this study, the authors have been developed the system for analyzing visual impact of a bridge and making zone map of view area. in order to support planning a bridge in landscape. Visibility, view angle, distance between view point and a bridge and angle of incidence which consists of vertical and horizontal components are analyzed in this system. And from these result making zone map of view area is feasible.
In this paper, we will introduce the following three unique methods to analyze fuel behavior in a spark ignition engine with EFI(Electronic Fuel Injection) system. (1) Direct and real-time observation of the fuel behavior by inserting micro CCD TV-camera into the transparent intake port. (2) Visualize observation of fuel cylinder wetting by using glass cylinder and fluorescence technique. (simultaneously photograph technique of schlieren image and actual image with one camera. With these three methods, we have succeeded in making possible an accurate observation and understanding of fuel behavior in firing operation.
For the study of a transient gas jet used in gas diesel engine, it is important to investigate the growing processes of the jet. In a certain region of injection velocity from a round nozzle, it has been confirmed that transient jets are composed of the laminar jet in the downstream and the turbulent jet in the upstream. We called the jet with characteristics of laminar sub-jet and called the jet with characteristics of turbulent main-jet. The image processing system was constructed to measure tip penetration and cross section of each jet at various times from the injection start. A jet was visualized by CCD camera using schlieren method and a jet was shown in digital by some image processing algorithms. The image processing developed in the shape-measurement will provide an effective method.
Experiments were conducted to investigate the combustion process in a disk-shaped constant volume chamber (100mm diameter and 30 mm thickness). The gas inside the chamber was the mixture of Methane and Air (101.3kPa) and the gas was ignited at the condition of swirl flow as well as stationariness. The deflaglation wave was visualized using a high-speed camera (4.500 FPS) with the aid of Schlieren optics. As a result, the turbulent process of the flame front was observed in detail and the high-speed video camera was useful to investigate the propagation of the flame front.
The flow in an air conditioning unit for automobile is studied experimentally at isothermal temperature conditions in a water tunnel to investigate the flow mixing mechanisms inside the unit at various angles of mixing plate. The mixing process of the flow is visualized by the laser induced fluorescence and the velocity field is studied quantitative by the particle imaging technique. The analized image of the two fluorescence dyes reproduces well the dispersion of heater flow in the full-scale unit, which indicates the usefulness of this visualization the technique of mixing flow.
Tuft angles on rotating bodies were investigated. On rotating bodies, not only the aerodynamic forces but also the centrifugal forces act on tufts. Thus, the tufts do not indicate the flow direction on the rotating bodies. First, an experiment for tufts' behavior on a rotating disk were performed. Needles were stood at the disk surface with different distances from the rotation center. Nylon mono-fiber tufts, that had 25.4mm length and 0.06mm crosssectional diameter, were attached at the points of the needles. The disk were rotated with several different speeds in the air at rest. Pictures of the disk were taken, and then, the angles of the tufts were measured. Secondly, the analysis taken account of the aerodynamic and centrifugal forces for the tufts was also conducted. A comparison of the experimental and analytical results showed good agreement. Lastly, the analysis was extended to predict the tufts angles on the rotating disk in a uniform flow. This condition is similar to the wheels of automobiles' tiers running at a constant speed.
Light-emitting region of cavitation bubble flows generated behind an orifce in a circular pipe has been visualized by optical methods. Xenon gas wsa dissolved in clear water for enhancement of weak emission from cavitation, and its effect on the luminous properties of the flows was investigated. Spacial emission profiles and shadowgraph images of clear water and water-xenon cavitation were obtained by photon counting and and ordinary photographic methods, and compared with each other. It was found that the emission property of the water-xenon cavitation was very similar to that of clear water, and the photographic method was directly apoplicable for the orifice cavitation flow under the enhanced condition.
Pressure sensitive luminescent paint based on Platinum Octaethylporphyrin (PtOEP) and oxygen-permeable silicon binder was produced referring to the formulation developed by the University of Washington. Thin coatings of the paint applied on aluminum plates have been tested in a climate chamber to investigate its luminescence characteristics. As a result, we have confirmed the observations previously reported for the same paint. It is also found that nonlinearity of the calibration curves is attributed to the submerged layers which are insensitive to oxygen. Problems concerning repeatability of the paint calibration curves were emerged. Our observation has suggested that the luminescence of the paint is relating not only to PtOEP molecular temperature but also to surrounding gas temperature.
Relationship between the color changes of thermochromic solutions and the temperature were investigated using a spectrometer. A sample solution was poured into a transparent cell, and transmitted light through the sample were measured as a spectrum. The temperature dependency of the spectra of each sample solution was discussed.
A new technique is devised to visualize distributions of heat flux on a heat transfer surfaces using thermo-chromatic liquid-crystal sheet. This method is based on the temperature difference produced by heat conduction within a thin thermal-resisting layer between iso-thermal substrate and liquid-crystal sheet.
A new auto-correlation, which is called a wavelet auto-correlation and expresses the statistical auto-correlation of any signal in terms of scale and time delay, is proposed and its main properties are also presented. As the practical application to fluid mechanics, wavelet auto-correlation is employed to analyze the velocity signals of the plane turbulent jet. From the distributions of wavelet auto-correlation coefficient, the similar structures of motions with various scales are observed instantaneously, and the period of vortex rings and apparent flapping motions can be easily determined in terms of period and time delay.
The present paper describes an application of Continuous Wavelet Transform to image data. This method has recently been studied by many researchers because of its new possibility in data analysis, not only on frequency but also on spatial domain. The effect of wavelet mother function on wavelet coefficient is examined using typical simple images. Visualized image data obtained by smoke wire method is also analyzed as a processing with numerical filter.
Soliton has been studied in the field of mathematics and physics. Although non-linear phenomena was difficult to be solved analytically, they can be analyzed numerically by an electric computer. In this paper, Numerical simulator was introduced for the soliton propagation with the KdV equation. The simulator works on MS-Windows so as to handle it quite easily and visually. Some new knowledges of separation in soliton propagation could be gained through the numerical simulation by the simulator.
The flow in diffusers with total divergence angle 6° and 8° was visualized by the surface tuft and tracer methods in which smoke and polystyrene microspheres . The movements of tufts, smoke and polystyrene microspheres with respect to time were monitored from a position perpendicular to the floor of diffusers, using two 8 mm video cameras. The behavior of flow differed depending on the total divergence angle 6° and 8° ; perturbation of flow with the total divergence angle of 8° was greater than that with 6° With the diffuser having a total divergence angle of 8°, separated flow occurred even at the inlet, and the area of reverse flow at coners was large. Futhermore, there was fairly strong irregular reverse flow at the outlet of diffuser. The behavior of reverse flow at the outlet was not identical at left corner and right corner. The axis of main flow did not agree with that of diffuser and varied with time. Reynolds numbers at the inlet in the experiment were represented by 3.1×104 and 6.2×104.
The purpose of this study is to clarify the effects of the existence of a guide vane in several curved diffusers with the different logarithmic spiral angle on the flow patterns. The flow visualizations were carried out by smoke wire method using High Speed Camera, and their results were compared with the data obtained by the wind tunnel experiment. As the result, it was found that the performance of the curved diffuser was improved considerably by the existence of a guide vane and affected by die logarithmic spiral angle, and the flow patterns obtained by the flow visualization agreed comparatively with the experimental result of the wind tunnel.
Inside of the heat exchanger of automobile, first the water flow comes into the inlet chamber and streams into many branch passages. Through these passages, the hot water is cooled by the surrounded air. Then the cooled water merges into the outlet chamber and flow out from the heat exchanger. Only a few reports are available to date concerning the mal-distribution of the flow rate and the technical remedy to obtain uniform flow distribution. This study aims to predict the flow patterns in a heat exchanger. Flow visualization, velocity measurement and numerical analysis are applied to the water flowin the tube array model. The results in laminar flow region show that the flow rates and patterns in tube array greatly depend on the mutual position of the tube arrays to the flow inlet and outlet of the model. It is shown that the uniform flow distribution in each branch passage can be realized by increasing the volume of the outlet chamber.
Authors have disclosed mechanics and correlations of the flow phenomena in the X-shaped intersecting ducts. In this study, experiments in four intersecting ducts are performed to investigate the vortex formation in the intersecting region and the flow rates at the end of each duct. The flow characteristics in six types of four intersecting ducts are clarified by using different lengths of intersecting zone.
Experiments are performed to investigate the vortex formation in and near the intersecting region by the particle tracing method using the ion exchange resin. Both the symmetric and asymmetric flows in two intersecting ducts with the different confluent and branching angles are also investigated. It is disclosed that the fluid control in the intersecting ducts with the confluent angle of 60° and the branching angle of 30°is easier than those with other angles.
This video film is produced for the purpose of lecturing on 'The flow around a body' in fluid dynamics. The film consists of three ports as follows. The first is an animation filem of two dimentional potential flow patterns around a circular with the aid of computer graphics. The second is the water flow patterns around a circular cylinder visualized using the hydrogen bubble method at Reynold's number 314. The third is the air flow patterns around a circular cylinder visualized using the mist streamline method at Reynold's number 3×104. This paper describers how to produce the video filems mentioned above.
For the purpose of education on fluid dynamics we edited the video film "Flow Visualization - the Edition on Vehicles ". It consists of four parts of flow visualization concerning space and aeroplanes, railways, automobiles and ships respectively. The methods of visualization are injection methods, optical methods, wall tracing methods, tuft methods, electric controlled tracer methods, computer assisted visualization and others. The impressions of students on this film seemed to be good.
Flow Visualization on inside and opening region in an Open Cavity Array is experimentally studied under the following conditions: the range of the depth-to-width ratio and Reynolds number are from 0.1 to 3.0 and from 2.0×103 to 5.5×104 repectively. Flow observation is studied by means of the following two technique: one is the scattering method of alminum powder on the water surface of the cavity array model, the other is dye tracer technique in the closed vertical model of the side wall. Flow pattern on inside region of the cavity array is influenced both the depth-to-width ratio and Reynolds number. Flow visualization on the opening region of the open cavity array by tracer technique is as follow: the movement of fluid particles is unsteady with chaotic movement on the different direction superimposed on the external main stream.
When junior high school students study their course of "Science", it is very important for each of them to personally contact and experience with each of natural behaviers. There are, however, many behaviers that couldn t be experienced by a student because they are micro or, on the country, super macro. In such cases, it is possible and is important for him to get a quasi-experience using such an audio-visual aid as a computer or a VTR. The sound is a kind of wave, but it is difficult to see directly the moving of air whitch is the medium of the wave. The newly developed method for visualizing the sound is to apply Laser light sheet to smoke line generated in a very low speed wind tunnel. Through this method, the transmission behavier of sound became clear vizualized.
An educational video film of fiuid dynamics visualized by various kinds of techniques helps to understands the flow mechanism and impress the beauty of the fluid flow to students. This educational video film may be categorized into three parts with the following aims. the first aims to understand the fluid mechanism and is used in lectures for students. The second aims to take an interest in fluid dynamics and to become familior with fluid dynamics and is used for orientation and seminars. The third aims to supplement the observations of flow in experiment and is used during experiment. This paper describes how to produse and utilize the video film mentioned above.
Pool boiling heat transfer from a horizontal wire to distilled water is studied under an atomospheric pressure condition. The horizontal wire is made of platinum. Diameter an length of the wire are 0.8 mm and 61.7 mm respectively. The horizontal wire is heated by a D.C. electric power source. Vaper bubbles on horizontal wire is photographed by a frash(25μs) of storoboscope. Vaper bubbles of nucleate boiling regime, critical heat flux point and film boining regime are visualized.
It is useful in the education on fluid dynamics to show animated computer graphics for some kinds, of flows, since they are dynamic phenomena. Therefore we have developed the personal computer softwares with animation. It was confirmed by tests that they helped students to understand and to be interested in fluid dynamics. Since the computer graphics are effective to visualize clearly only necessary subjects, they are expected to be practical-ly used for engineering education, especially for fluid dynamics.
Understanding of fundamental concepts of fluid dynamics in engineering course of university is very important. When students learn physical phenomena in fluid flow, it is very useful to draw the animated flow patterns on. a display by a personal computer. In this paper, two examples of the program for computer aided education, which are coded by the BASIC or FORTRAN, are presented. The first one is a program for drawing 2-dimensional and 3-dimensional pressure distribution in the flow issuing, from a wind tunnel, and the second is interpolation program for data arrangement. By this program, they can understand better for physical phenomena and correct their mistake.
We can remember and recognize visual scenes that we already met. How then, exactly can we recognize colors of those scenes? To answerthis question, we performed an experiment that consisted of two stages; a memory stage and a recognition stage. In the memory stage, subjects memorized 20 pictures successively. In the following recognition stage, the subjects observed 40 pictures and judge, by forced choice method, if each picture was the same as that memorized. Those 40 pictures consisted of (a)ten pictures memorized, (b)another ten pictures changed either their chromatic or luminance contrast of the memorized pictures and (c)the other twenty pictures never presented before. Subjects tended to idetify a picture changed to higher chromatic contrast with the picture memorized. Our result suggested that we can color the image uniquely toward more saturated colors than those actually memorized.
A multispectral image is a set of power spectral density functions. Each function is a mixture of power spectral density functions of many components included in the measured object. Independent component analysis (INCA) can extract the original functions from the mixtures with the assumption of independence of the original components. In the conventional algorithms of INCA, the number of elements of each mixure must coincide the number of the independent components. This limitation is severe in processing of multispectral images. In this paper, we propose an improved method that can be used when the number of elements of the mixure is larger than the number of the independent components.
A spectroscopic image analysis based on a subspace method requires orthogonal basis functions which can represent the objective spectrum by the linear combinations. But, It is difficult to realize filter functions corresponding to the spectral sensitivity of orthogonal basis functions. Then we propose a new algorithm to synthesize orthogonal basis functions from broad-band filters using a generalized inverse matrix. Our system consists of a few image sensors and different broad-band filters and does not use scanning process. The resultant spectroscopic images are compared, with the spectroscopic image obtained by conventional method and some components in an image are classfied.
Discrimination of color images and its electro-optical realization are described. In the hybrid system for color image discrimination, a 3-D vector color image is transformed into a 2-D vector image by projection onto a color plane, which is defined as complex plane. In the optical processing, correlation between two images is performed by mateched spatial filtering in which the filter is synthesized by the projected complex image of the reference pattern. The correlation peak is interfered with a refrence beam in order to detect the phase of the correlation result, because the result of the color image correlation is obtained as complex value. In this paper, the method of color image correlation and a technique for the optical implementation of a colorimage correlation are discribed, and the experimental result using a liquid crystal spatial light modulator is also included.
Recently IR thermography has been utilized in Japan and Europe in the wind tunnel tests to obtain not only the surface temperatre but also heat flux distribution of the model. The heat flux is deduced from the surface temperature history assuming 1-dimensional semi-infinite conduction of heat. To assure its quantitative capability, there are some issues to be characterized and resolved such as accuracy of the. acquired temperature and the degree of realization of assumed thermal model, etc. Measures and correections for the accuracy enhancement at NAL are discussed.
Using the rainbow holographic technique, a color or an achromatic image can be obtained from the superposition of various rainbow holograms on a single plate. Since the color of the reconstructed image depends on the observation angle, the desired image is obtained at a specific viewing position. Using Kogelnik's theory an analysis of the image's color variation under different recording and reconstruction conditions is performed. The analysis helps to find adequate recording parameters to improve the luminance of the final reconstructed image.
An application of genetic algorithms to particle image tracking has been studied to simultaneously search out velocity vectors of a large number of moving tracer particles. Since its concept becomes to a combinatorics for identifying particles between two sequential digital flow images, the authors make use of the genetic algorithms for solving the combinatorics. The particle identification is realized by optimizing the evolutive gene strings which are encoding the particle combinations. The previous paper had proposed the idea of 2-dimensional particle image tracking method by the genetic algorithms. The idea has the excellent advance to a 3-dimensional particle image tracking method The fundamental performance of this method is evaluated by the image analysis for a numerical simulation.
In this paper, a multiple-layer neural network model has been applied to the Fourier transform method in 2-D Particle Image Velocimetry to improve the measurement accuracy. The input information of the neural network is the complex phase that is extracted from the Fourier transforms of two images captured in a short time interval, and the output is the spatial shift of the pattern on the images. The learning is performed by a conventional error back propagation method. The performance test shows that the present method is robust against velocity fluctuation and the computing time can be reduced to about 75% of that of the original Fourier transform method.
The measuring method of flow velocity field by image analysis based on a pattern matching and a genetic algorithm is proposed in this investigation. The genotype consists of two components of the pattern movement vector, and it is fixed to all pixels for the measurement. In this method the operation of selection and crossover is planed to decrease the number of error velocity vector. It is demonstrated that the image analysis using the proposed GA model is significantly effective to measure of the actual flow velocity field.
Quantitative thermal flow visualization using image processing is very useful for obtaining velocity vector or temperature profiles in a thermal flow field. The velocity vector and temperature profiles are able to be simultaneously measured from color images visualized by a thermo-sensitive liquid crystal suspension method. The temperature profile, however, partly lacks information on temperatures in the field because of the narrow temperature range in which the liquid crystals present color. Temperature profiles over the entire flow field, therefore, are unable to be obtained. This paper proposes a new algorithm for estimating unmeasurable temperatures from measurable temperatures. As the first step, an unsteady heat conduction field is modeled by using composite dynamic/static recurrent neural networks from the known information on temperatures. Consequently, the unknown information on temperatures is estimated from the neural network model.
Three-dimensional density distribution can be reconstructed using tomography technique from interferogram images. Conventional tomography techniques have low accuracy with a few interferogram images and truncated images. To improve the accuracy of the reconstruction, a new tomography technique is proposed. In the present method, density distribution is assumed to be mainly effected by diffusion processes, and to be expressed as the summation of elementary density distributions. The tomography is carried out as the optimization of the arrangement of elementary density distributions. As optimization technique, genetic algorithm (GA) is introduced. The GA usually needs lots of calculation time. In this study, the two-dimensional density distribution in cross sections are stacked, in order to construct the three-dimensional data. As an initial condition of one cross section, the converged data at previous cross section are used, resulting in the less calculation time. The three-dimensional density distribution is reconstructed using the present method (GA) and conventional Filtered Back Projection method (FBP). The target flow field is density stratified field, which is caused by the downward helium jet into air. Both the GA and FBP can reconstruct the three-dimensional density distributions. The GA shows high effectiveness with reconstructing the three-dimensional data with a few images and truncated images.
This paper presents a new measurement system for three-dimensional temperature distribution in a rotating Rayleigh-Benard convection based on color image processing. This system is an extension of two-dimensional temperature measurement system in which thermo-sensitive liquid-crystal suspension method is adopted for flow visualization and neural network is used for correlating between color and temperature. Interpolating two-dimensional temperature distributions in vertical plain by B-spline function, three-dimensional temperature distribution in the fluid layer was obtained.
In recent years, the need for nonintrusive diagnostics of gaseous flows has motivated the development of optical techniques such as LIF, which is the most attractive method for an analysis of the flow field structures. IfO 2-LIPF is feasible to visualize air flows, no seeding of the flows and no consideration of toxicity and corrosiveness may be required. However, since the fluorescence of oxygen molecules is very weak and in the ultraviolet region, there may be some difficulties in detecting the fluorescence signal. In this study, a system is developed to visualize supersonic oxygen flows using O 2-LIPF, which consists of an ArF excimer laser, a high-sensitivity CCD camera and an image intensifier. Three spectral filters are selected to eliminate the scattered laser beam, and three images visualized through them are compared.
In this paper, the generation mechanism of jet noise containing discrete frequencies with peaks at a specific frequency was studied by the digital image processing. The flow of subsonic jet issuing from a nozzle with exit divergent angle 20 degrees was photographed by a high-speed video camera included Schlieren device. The phase speed and distance of vortex rings were calculated by the digital image processing. It was clarified that the fundamental frequency of the noise power spectrum was closely related with the separation vortex, and agreed well with the frequencies of vortex rings released from the nozzle.
One of the most promising exhaust nozzles for a future super/hypersonic transport will be a non-axisymmetric variable geometry nozzle and more than likely the ejector nozzle which introduces bleed/bypass air from the intake section to solve inlet/engine flow mismatch, cool nozzle walls, reduce external drags, and then improve overall performance of the propulsion system. In the present study, scale model tests with a typical 2D-CD ejector nozzle have been carried out to investigate the internal flowfield using optical flow visualization techniques. A specially designed Mach-Zehnder interferometer has been used to get equi-density interferograms for internal flow near the throat region. A multicolor schlieren method has been also used to demonstrate shear layers and waves. A CFD prediction has been carried out and compared with the test result.