Toward an affordable two-equation structure-based turbulence model

Flow fields of engineering interest involve complex turbulence dynamics. Many times the fluid dynamics must be investigated computationally as detailed experimental investigation is precluded by the severity of the operating environment. Computational simulation of complex turbulent flows necessitates the use of turbulence models. While many standard two-equation models provide adequate results for some engineering flow fields, they lack much of the detailed dynamics necessary to accurately reflect the important physics of the flow field.; The Algebraic Structure-Based Model (ASBM) is presented here. Its algebraic formulation ensures computational efficiency while the structure basis of the model captures the important turbulence physics. The ASBM draws heavily on Rapid Distortion Theory (RDT) and Direct Numerical Simulations (DNS) for model constants and closure.; The ASBM was applied to compute a variety of flow solutions to demonstrate its accuracy. Homogeneous mean flow solutions were computed for irrotational and rotational mean deformations. The effects of frame rotation were also included. The homogeneous results show that the model predictions match the RDT limit states of turbulence, agree with DNS and experimental results for homogeneous shear, agree with DNS results for homogeneous shear in a rotating frame, and display the proper material indifference of 2D turbulence to rotation.; One-dimensional spatially-developing free shear layer solutions were computed for mixing layer, plane and axisymmetric jet flows. The free shear layer analysis compared solutions using the standard k-ϵ model, Wilcox's k-ω model, and the ASBM coupled with the k-ϵ and k-ζ scale equations (where ζ is the large scale enstrophy). Results show that ASBM k-ϵ solutions agree with experimental results and compute the correct spreading rates for all flows.