著者

一宮 昌司 中村 育雄

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:18848346)

巻号頁・発行日

vol.78, no.788, pp.794-810, 2012 (Released:2012-04-25)

参考文献数

62

被引用文献数

4 4

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Investigations on the definition and randomness of turbulence was reviewed at first. Then, the Kolmogorov complexity which measures the randomness were introduced. Numerical and graphic data in the mixing layer which was formed downstream of two-dimensional nozzle exit were compressed with the aid of a compression program. Approximated Kolmogorov complexity, AK, and normalized compression distance, NCD, were obtained. The AK indicated the regularity of the laminar flow and the randomness of the turbulent flow quantitatively. The NCD of the numerical value varied with data length. Between the same data, it approached zero, yet, on the other hand, between different data, it approached unity as the data length increased. The NCD of the numerical value in the natural transition process in the mixing layer increased monotonically downstream. Thus the NCD appears to be the measure of the transition process. In the natural transition process in the mixing layer, the AK of the numerical value and the NCD of the graphic data did not change monotonously in the downstream direction. Thus they contain some uncertainty for the measure of the transition process.

著者

中村 育雄

出版者

一般社団法人 日本繊維製品消費科学会

雑誌

繊維製品消費科学 (ISSN:00372072)

巻号頁・発行日

vol.56, no.5, pp.396-397, 2015-05-20 (Released:2017-11-28)

著者

古屋 善正 中村 育雄 山下 新太郎

出版者

一般社団法人日本機械学会

雑誌

日本機械学會誌 (ISSN:00214728)

巻号頁・発行日

vol.81, no.720, 1978-11-05

著者

清水 徹 横川 明 鈴木 基光 中村 育雄

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.51, no.469, pp.2908-2915, 1985-09-25

被引用文献数

1

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種種の乱れ発生要素を入り口に設けたく形断面流路における繊維懸濁液流れの濃度むらを比較的高い濃度にわたって測定し,その管軸方向への分布や平均濃度および平均流速に対する依存症について検討した.この結果,流れの乱れによる濃度むらの減少には限界値が存在すること,また十分に発達した流れ場における繊維懸濁液の濃度むらは非ニュートン流体の広義のレイノルズ数で整理できることが明らかになった.

著者

辻 義之 宮地 圭 鈴木 孝裕 中村 育雄

出版者

日本機械学会

雑誌

日本機械学會論文集. B編 = Transactions of the Japan Society of Mechanical Engineers. B (ISSN:03875016)

巻号頁・発行日

vol.70, no.695, pp.1679-1686, 2004-07-25

参考文献数

17

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In a zero-pressure gradient turbulent boundary layer, the multi-point measurement by 24 ch I-probes is performed. The relation between coherent structures and logarithmic velocity profile is studied by way of proper orthogonal decomposition technique and the stochastic estimation. It is found that the existence of coherent structures are necessary condition for the universal velocity profile, however it is not enough. Small-scale motions are also necessary to realize the log-law profile. The probability density profile in the overlap region is studied, and as a result, the invariant assumption of PDF in relation to the coherent structure is obtained. It was also evaluated how the velocity fluctuation in the log-region is affected by the coherent structures.