著者

須賀 一彦 Timothy J. CRAFT Hector IACOVIDES

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 B編 (ISSN:03875016)

巻号頁・発行日

vol.71, no.711, pp.2725-2733, 2005-11-25 (Released:2011-03-03)

参考文献数

21

被引用文献数

1

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This paper reports the development of a refined wall-function strategy for the modelling of turbulent flows over smooth and rough surfaces. In order to include the effects of fine-grain surface roughness, the present study extends a more fundamental work on the development of advanced wall functions of general applicability. The presently proposed model is validated through comparisons with data available for internal flows through channels, pipes and for external flows over flat plates with both smooth and rough surfaces. Then, its further validation in separating flows over a sand dune and a sand-roughened ramp as well as a smooth ramp is discussed. The validation results suggest that the presently proposed form is successfully applicable to a wide range of attached and separated turbulent flows over smooth and fine-grain rough surfaces.

著者

岡田 空海地 里中 直樹 藤原 徳一 上村 匡敬 須賀 一彦 柴田 政明

出版者

一般社団法人日本機械学会

雑誌

設計工学・システム部門講演会講演論文集 (ISSN:13480286)

巻号頁・発行日

vol.2012, no.22, pp."3406-1"-"3406-8", 2012-09-26

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Recently various measures are made towards realization of low carbon society. Water-power generation is one leading policy. However, development of the small-scale water-power generation to power consumption, such as a plain part, is not fully progressing. Therefore, this research aims to develop the micro water-power generation equipment which used the new type of turbine. For developing new type of turbine called the tornado type, its prototype model experiment and numerical simulation are performed and the various parameters of the turbine are determined and the manufacturing checks are performed. Then, we conducted the profile data of turbine generated by the 3D-CAD, production of the prototype model by using RP equipment, and the check experiments of operation by the produced the prototype model. Moreover, cutting of the actual turbine by using 5-axis processing machine with the tool path data generated by the 3D-CAM was also performed. As a result, we confirmed that the rapid prototyping model is possible to rotate in the water flow. In addition, in the actual cutting experiment of the turbine, we confirmed that it is possible to manufacture of the turbine by 5-axis processing machine.

著者

須賀 一彦

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. B編 (ISSN:03875016)

巻号頁・発行日

vol.70, no.697, pp.2386-2393, 2004-09-25

被引用文献数

1

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Modeling the pressure-diffusion process is discussed to improve the prediction of turbulent recirculating flows by a second moment closure. Since the recent DNS research of a turbulent recirculating flow suggeted that the pressure-diffusion process of the turbulence energy was significant in the recirculating region, the present study focuses on the rapid part of the process consisting of the mean shear. This rapid pressure-diffusion model is developed for the Reynolds stress equation using the two-component limit turbulence condition and added to a low Reynolds number two-component-limit full second moment closure for evaluation. Its effects are discussed through applications of turbulent recirculating flows such as a trailing-edge and a back-step flows. Encouraging results are obtained though some margins to be improved still remain.