2021-10-24T09:49:52Zhttps://soar-ir.repo.nii.ac.jp/oaioai:soar-ir.repo.nii.ac.jp:000129402021-03-01T11:14:43ZA Proposed Model for Correlation Functions in Isotropic Turbulence等方性乱流の相関モデル大路, 通雄39707平山, 俊雄39708An attempt is made to simulate the decay process of homogeneous isotropic turbulence in an incompressible fluid by a model function f(r) = exp[b - √c2r2+b2] for the longitudinal double velocity correlation coefficient f(r), where b and c are adjustable form parameters. It is assumed that c is equal to a constant c for simplicity, and the equation for the decay of turbulent energy and Loitsiansky' s invariant theorem are combined together to determine b as a function of the decay time t. The result is expressed by a simple integral including the modified Bessel functions Kn (up to n = 3). Associated temporal changes of some interesting quantities such as the length scales, the energy decay law, the turbulence Reynolds number as well as the triple velocity correlations are also discussed. They are in qualitative agreement with the case of actual turbulence, especially as the final stage of decay is approached. For the initial stage, a little more sophisticated model is expected to be promising.Article信州大学工学部紀要 36: 11-22 (1974)departmental bulletin paper信州大学工学部1974-07-25application/pdf信州大学工学部紀要3611220037-3818AN00121228https://soar-ir.repo.nii.ac.jp/record/12940/files/Engineering36-02.pdfjpn