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Development of a tomographic PTV
도덕희,조경래,Young Ho Kim 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.12
A new tomographic PTV (Tomo-PTV) was proposed, and then its performance was compared with that of tomographic PIV (Tomo-PIV). To construct the new tomographic PTV for calculation of vector fields, an affine transformation was introduced. The vectors obtained by match probability method were used as the initial data for the final vectors. Four camera-based tomographic PTV and PIV systems were constructed. By introducing a new factor called degree of reality, the real particles were easily separated from the ghost particle groups. Two flow fields, a ring vortex and an impinging jet, were measured by the constructed tomographic PTV and the conventional tomographic PIV. Eight image frames (two consecutive image frames for each camera) were used for the construction of threedimensional voxel images. The construction method used for the voxel images was MLOS-MART.
디지털화상처리에 의한 음장의 가시화기법개발에 관한 연구
도덕희,김동혁,강동림 한국마린엔지니어링학회 2000 한국마린엔지니어링학회지 Vol.24 No.4
A new acoustic field visualization technique is introduced in this study. Small particles of which density is small enough to follow up the air used for the noise field visualization. In order to quantify the noise, PIV(Particle Imaging Velocimetry) has been constructed. When the driving frequency is in the vicinity of the resonance frequency of the simplified 2-dimensional muffler system, an acoustic streaming is shown and of which velocity distribution is obtained through PIV technique. It is experimentally proved that the present technique is able to visualize and quantify the acoustic fields.
디지털 화상처리를 이용한 유동장의 비접촉 3차원 고속류 계측법의 개발
도덕희 한국마린엔지니어링학회 1999 한국마린엔지니어링학회지 Vol.23 No.2
A new algorithm for measuring 3-D velocity components of high speed flows were developed using a digital image processing technique. The measuring system consists of three CCD cameras an optical instrument called AOM a digital image grabber and a host computer. The images of mov-ing particles arranged spatially on a rotation plate are taken by two or three CCD cameras and are recorderd onto the image grabber or a video tape recoder. The three-dimensionl velocity com-ponents of the particles are automatically obtained by the developed algorithm In order to verify the validity of this technique three-dimensional velocity data sets obtained from a computer simu-lation of a backward facing step flow were used as test data for the algorithm. an uncertainty analysis associated with the present algorithm is systematically evaluated, The present technique is proved to be used as a tookl for the measurement of unsteady three-dimensional fluid flows.
도덕희,김동혁,오철,홍성대,박성룡,황태규,Doh Deog Hee,Kim Dong Hyuk,Oh Cheol,Hong Seong Dae,Park Seong Ryong,Hwang Tae Gyu 한국마린엔지니어링학회 2005 한국마린엔지니어링학회지 Vol.29 No.2
Experimental studies on the characteristics of ice slurry flows in a circular pipe is rare due to the deficiency of conventional measurement techniques. In this report the flow characteristics are quantitatively investigated by the use of PIV technique concerning the Ice Packing Factor(IPF) and the power changes of pump motor It was experimentally verified that the power loss does not increase any more at a certain IPF value.
도덕희,염주호,조경래,민성기,김명호,유경원,유남현 한국수소및신에너지학회 2012 한국수소 및 신에너지학회논문집 Vol.23 No.6
Concentration fields of solid powder in a liquid fuel were quantitatively measured by a visualization technique. The measurement system consists of a camcoder and three LCD monitors. The solid powder (glass powder) were filled in a head tank which was installed over a main mixing tank (D x H, 310 x 370 mm). The main mixing tank was filled with JetA1 fuel oil. With a sudden opening of the upper tank by pressurized nitrogen gas with 1.9 bar, the solid powder were poured into the JetA1 oil. An impeller type agitator was being rotated in the mixing with 700 rpm for the enhancements of mixing. Uniform visualization for the mixing flow field was made by the light from the three LCD monitors, and the visualized images were captured by the camcoder. The color images captured by the camcoder The color information of the captured images was decoded into three principle colors R, G, and B to get quantitattive relations between the concentrations of the solid powder and the colors. To get better fitting for the strong non-linearity between the concentration and the color, a neural network which has strong fitting performances was used. Analyses on the transient mixing of the solid powders were quantitatively made.