A new algebraic structure-based turbulence model for rotating wall-bounded flows

A primary goal of RANS based modeling is to determine the Reynolds stress tensor in order to close the turbulence problem at the mean velocity level. However, the Reynolds stresses alone are not sufficient to characterize complex turbulent flows adequately. More independent information on the turbulence is needed, especially in presence of rotation. For example, complementary information can be given by the one-point structure-dimensionality tensor. It gives a measure of gradients in the turbulence—if the turbulence structures are preferentially aligned with one direction, then the dimensionality is smaller in that direction.; This work uses hypothetical turbulent eddies to bring awareness of turbulence structure into the turbulence model. Averaging over an ensemble of eddies produces a set of one-point statistics, representative of the eddy field, and a set of equations relating the Reynolds stresses and the structure dimensionality to the eddy statistics. An algebraic model for the eddy statistics is constructed in terms of the mean deformation and two turbulent scales; the turbulent kinetic energy and the large-scale enstrophy. The algebraic model is sensitized to the presence of walls by a blocking scheme, which ensures proper asymptotic behavior for the Reynolds stresses.; Contrary to existing ad-hoc definitions of a second scale equation, the large-scale enstrophy equation has a fundamental background; it is derived from the large-scale vorticity equation. Its terms represent large-scale processes, and their exact form provides valuable guidance when making model choices for their closure. The exact forms also provide insight into making these model choices consistent with the asymptotic behavior of the exact terms near walls.; The model produces realistic Reynolds stresses and structure tensors for different combinations of mean strain, mean rotation, and frame rotation. The complete model, with evolution equations for the turbulent scales and algebraic equations for the turbulence structure, was investigated. Although results for a channel in a streamwise-rotating frame overestimated stabilization, the model produced adequate results for channel flows in fixed and in spanwise-rotating frames of reference.