Flow-induced acoustic resonance in a piping system containing closed coaxial side-branches was investigated experimentally. Resonance characteristics of the piping system were examined by a microphone. The results revealed that the resonance frequencies of the shear layer instability were locked in corresponding to the natural frequencies of the side-branches. Phase-averaged velocity fields were obtained two-dimensionally in the junction of coaxial side-branches by dynamic particle image velocimetry (PIV), while the acoustic resonance was induced at the first and second hydrodynamic modes. The DPIV can acquire time-series velocity fluctuations, then, two-dimensional phase delay maps under resonance and off-resonance conditions in the junction of coaxial side-branches were obtained. Experimental results show that the proposed phase delay map method costs less experiment and computation time and achieves a better accuracy and repetition than the phase-locking technique. In addition, the phase delay map method can obtain phase difference under the different frequency components.
Broad survey on the distribution of the air dose rate has been performed after the accident at the Fukushima Daiichi nuclear power plant continuously. The surveyed monitoring datasets are stored in a database and are made available to the public. Recently, the size of the datasets have been significantly increased as more detailed measurements in space and time are available, and effective reduction of the size of the datasets is necessary for visualizing and exploring such large scale datasets. However, if the datasets are not carefully reduced, we often miss a part of important features of the distribution data. Therefore, we develop an effective Level of Detail control (LoD) method for retaining critical features of the distribution. In the method, the global and local features of the distribution are extracted by means of differential topology analyses. Then, the simplified data is created by edge collapse operation with taking into account these features of the data.
In medical, scientific and other fields, transparent surface visualization is useful to investigate inner 3D structures. Such visualization usually uses the polygon graphics, where the polygons must be sorted along the line of sight. The sorting, however, requires long computation time for large-scale data. Besides order of polygons in the sorting often becomes indefinite especially for intersecting surfaces. On the other hand, the stochastic point-based rendering was proposed as a transparent-rendering method which does not require sorting. In addition, the important feature of this method is to generate the particles first only once. The purpose of this paper is to create 3D fusion images, such as volume, surface, cross-section surface and contour line, based on the stochastic point-based rendering.
This paper describes an application of CAVE system for developing a design guide of stent. Computational Fluid Dynamics (CFD) was performed on nine realistic aneurysms, and its results were observed using CAVE system. Owing to the capability of 3D visualization for supporting human understanding in complex information, we can predict the optimal position of strut deployment to reduce aneurysm flow. The position predicted from the observation is inside the inflow streamlines entering an aneurysm (BOI). As the result of strut deployment on predicted location (inside the BOI), struts reduces aneurysm flow effectively compared to that of outside of the BOI.
There are many studies on various scientific fields. It is important for any research fields to spread the information and to gain understanding from the public for further development. However it is difficult for people of non-scientific background to understand the research theme and its results. Thus, visualization of the research results by illustration is useful for easier understanding of any people. I am now working as a member of scientific research laboratory to visualize science, and trying to demonstrate the importance of the visualization. I visualize the scientific result not from the science-educated point of view, but from the art and design-educated point of view. In this paper, specific example on how non-scientist is communicating with the scientists to visualize their science is reported. Also the role and potential of art in the scientific field from the artistic point of view is discussed.
The importance of psychological measurement and evaluation has been growing, such as stress evaluation, product evaluation and design, and mental training in various scenes of our life. A questionnaire survey is generally conducted as a quantitative measurement method for psychological data, and this data is useful to understand the general mental states of a person. In contrast, an interview survey is also essential for clarifying aspects of an individual’s mental state in detail. However, it is difficult for experts and people who are not experts to share the understanding of the interview results, meaning the mental state, because interpretation of these results requires advanced skills. Therefore, the society for visualization of mind was inaugurated last October in order to create an easy to understand visualization of an individual’s mental state. This paper introduces the society’s effort to visualize the mind using an interdisciplinary approach based on psychology, information science, and fluid dynamics.