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A Contribution to the Energy Decay Law of Isotropic Turbulence in the Initial Period
https://jaxa.repo.nii.ac.jp/records/34592
https://jaxa.repo.nii.ac.jp/records/34592065fbe08-5d69-4b60-bc9f-43e5100fd53f
| 名前 / ファイル | ライセンス | アクション |
|---|---|---|
SA2404809.pdf (1.7 MB)
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| Item type | 紀要論文 / Departmental Bulletin Paper(1) | |||||||
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| 公開日 | 2015-03-26 | |||||||
| タイトル | ||||||||
| タイトル | A Contribution to the Energy Decay Law of Isotropic Turbulence in the Initial Period | |||||||
| 言語 | en | |||||||
| 言語 | ||||||||
| 言語 | eng | |||||||
| 資源タイプ | ||||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_6501 | |||||||
| 資源タイプ | departmental bulletin paper | |||||||
| 著者 |
TSUJI, Hiroshi
× TSUJI, Hiroshi
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| 出版者 | ||||||||
| 出版者 | 東京大学航空研究所 | |||||||
| 出版者（英） | ||||||||
| 出版者 | Aeronautical Research Institute, University of Tokyo | |||||||
| 書誌情報 |
東京大學航空研究所報告 en : Report/Aeronautical Research Institute, University of Tokyo 巻 25, 号 5, p. 87-108, 発行日 1959-03 |
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| 抄録（英） | ||||||||
| 内容記述タイプ | Other | |||||||
| 内容記述 | Of the energy decay laws of isotropic turbulence in the initial perid, the socalled linear decay law and Lin's decay law are well known. The linear decay law was first derived theoretically by Batchelor on the assumption of partial self-preservation of velocity correlation functions, but there is involved a self-contradiction that it eventually necessitates the premise of complete self-preservation of correlation functions. On the other hand, Lin's decay law, which was derived by assuming the similarity of spectrum for wave numbers except at small end, holds only after neglecting the self-preservation of correlation functions near γ=0,very important characteristics confirmed by experiments. Therefore, at first in this paper, we criticize these decay laws and find out the points of self-contradiction inherent in these two theories. Then eliminating the above mentioned points of self-contradictions and making a simple assumption that the partial self-preservation of correlation functions holds and S and G stay constant during decay, as confirmed by experiments, we try to calculate the decay curves by solving the energy decay equation (5.7), ζd^2ζ/dξ^2+C(dζ/dξ)^2-E(dζ/dξ)^3/2=0,which is derived from the energy equation (2.10)and the vorticity equation (3.1), in which ζ-U^2√<μ^2>, ξ=χ/M, C=(7/15)G-2,E=(7/3)S√<R_M/10,R_M=UM/ν, S=-<(∂υ/∂χ^3)>^^^-/[<(∂υ/∂χ)^2>^^^-]^3/2 and G=<υ^2>^^^-<(∂^2υ/∂χ^2)^2>^^^-/[<(∂υ/∂χ)^2>^^^-]^2. Since this equation contains statistical quantities of turbulence, S, G and R_M, as parameters, the decay curves obtained by solving this equation vary with the initial conditions of turbulence generation and also with the values of these parameters. Thus, we can, through such parameters, examine quantitatively the effect of the initial conditions upon the energy decay of turbulence. This equation is actually solved by numerical integration for cases corresponding to the experiments done by the present author and by Batchelor and Townsend. The calculated results are in good agreement with these experimental values. | |||||||
| ISSN | ||||||||
| 収録物識別子タイプ | ISSN | |||||||
| 収録物識別子 | 0376-1061 | |||||||
| 書誌レコードID | ||||||||
| 収録物識別子タイプ | NCID | |||||||
| 収録物識別子 | AA00514444 | |||||||
| 資料番号 | ||||||||
| 内容記述タイプ | Other | |||||||
| 内容記述 | 資料番号: SA2404809000 | |||||||
