Numerical study of adaptive grids for laminar flow in a suddenly expanding channel

In this article, a numerical study was carried out to study the dynamic adaptive grid method, based on the concept of the equidistribution method. The article explores a method for adapting the computational grid to solving two-dimensional Navier-Stokes differential equations, which describe the physical processes of gas dynamics specifically for the problem of a two-dimensional channel with an expansion coefficient (H/h) = 2. Different flow characteristics were calculated at different Reynolds numbers Re = from 100 to 1000, to get the actual thread behavior. Calculations are performed for laminar flow mode. The results of the longitudinal velocity profiles in different sections of the channel and the length of the primary and secondary vortices are obtained with a change in the Reynolds number after the ledge. For the numerical solution of this problem, a second-order accuracy McCormack scheme was used. To confirm the adequacy and reliability of the numerical results, a careful comparison was made with the experimental data of Armaly V.F. et al., taken from the literature. It is also shown that as a result of using this method of adaptive grids, it is possible to improve the numerical accuracy obtained for a given number of node points. It is shown that the existing method of multiple 2D adaptive meshes makes it easier to concentrate meshes in the required areas. This method should prove useful for many Navier-Stokes flow calculations.