IDENTIFICATION OF THE "LOCAL" HOMOGENEOUS MIXING DEGREE IN THE DIRECT NUMERICAL SIMULATION OF TURBULENT MIXING
Yu. V. Yanilkin, A. R. Guzhova, L. I. Degtyarenko, O. G. Sinkova
VANT. Ser.: Mat. Mod. Fiz. Proc 2020. Вып.3. С. 3-10.
The paper describes a model used to identify the local (in space) degree of homogeneous mixing in the direct numerical simulation of the turbulent mixing of two immiscible fluids. The term "local" means that the degree of homogeneous mixing is identified for each mixed cell containing two materials. The model is based on the analysis of a mixed cell from viewpoint of the ability to reconstruct a material-material interface in such a cell. If the interface is recoverable, it is assumed that materials are not mixed in the cell, otherwise materials are in the mixed state. The model was tested on the classic problem of turbulent mixing under the Rayleigh-Taylor instability conditions due to a continuously accelerating interface between two fluids (gases) of different densities. Both the 2D and 3D numerical simulations of the problem were performed. Results of simulations with the proposed model for the integral (in space) degree of homogeneity were compared with those obtained using the known model. There is a satisfactory agreement of results that allows stating the proposed model adequacy. Keywords: Rayleigh-Taylor instability, turbulent mixing area, direct numerical simulation, a homogeneous mixing degree, the EGAK code.
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English
