A modification of the values of three constants C_1, C_2 and C_3 in the standard K-ε turbulence model is proposed, based on the empirical law of decay obtained for nearly homogeneous in-cylinder turbulence. Since the decay exponent of Reynolds numbers for in-cylinder turbulence is found to be different from that for steady ducted flow just behind a turbulence-generating grid, the C_2 value is modified first, followed by the C_1 and C_3 values, which depend on the C_2 value. The derived C_2 value of 1.40 is smaller than that in the standard K-ε turbulence model, but the C_1 value, 1.40, is close to that of the standard one. The C_3 value, -1.05, is very close to the recommended value by Morel et al. for the case of a unidirectional axial compression.
|ジャーナル||JSME International Journal, Series B: Fluids and Thermal Engineering|
|出版ステータス||出版済み - 2 15 1989|