Fluid flow simulation in a T-connection of square pipes using modern approaches to turbulence modeling

In the article the description is given of the new technique for fluid flow simulation in Tjoints of square pipes, based on the numerical solution of the three-dimensional Navier-Stokes equations. As part of the methodology for solving these equations, a modern approach to modeling turbulence is used - the zonal EARSM-LES approach, in which in areas of intense vortex formation, and where it is necessary to increase the accuracy of the solution obtained, the LES turbulence model is used, in the rest of the area the Reynolds stress model EARSM is used. The EARSM model simulates the transfer of all components of the Reynolds stress tensor, which leads to an increase in accuracy when calculating complex flows, in particular, flows near dihedral angles. The article describes a mathematical model based on the Reynolds-averaged three-dimensional Navier-Stokes equations, as well as the equations of the EARSM-LES hybrid model used. The comparison of the use of different basic models, such as EARSM and SST, in the RANS-LES approach for 3D problems containing dihedral angles. It is shown that the EARSM model gives an increase in accuracy compared to the SST, which is explained by taking into account the anisotropy of the Reynolds stress tensor in it, the velocity profiles and components of the Reynolds stress tensor according to the EARSM model are predicted much more accurately than using the SST. Due to this, the EARSM-LES model ultimately gives better results in terms of velocity and tensor components than the SST-LES model. The Russian software package for computational fluid dynamics and engineering analysis LOGOS was used to simulate the tasks presented in this paper.