Affiliations: [a] Mechanical Engineering Faculty, Sahand University of Technology, Tabriz, Iran | [b] Mechanical Engineering Faculty, Division of Biomechanics, Sahand University of Technology, Tabriz, Iran | [c] Chemical Engineering Faculty, Sahand University of Technology, Tabriz, Iran
Abstract: Laminar, turbulent, transitional, or combine areas of all three types of viscous flow can occur downstream of a stenosis depending upon the Reynolds number and constriction shape parameter. Neither laminar flow solver nor turbulent models for instance the k–ω (k–omega), k–ε (k–epsilon), RANS or LES are opportune for this type of flow. In the present study attention has been focused vigorously on the effect of the constriction in the flow field with a unique way. It means that the laminar solver was employed from entry up to the beginning of the turbulent shear flow. The turbulent model (k–ω SST Transitional Flows) was utilized from starting of turbulence to relaminarization zone while the laminar model was applied again with onset of the relaminarization district. Stenotic flows, with 50 and 75% cross-sectional area, were simulated at Reynolds numbers range from 500 to 2000 employing FLUENT (v6.3.17). The flow was considered to be steady, axisymmetric, and incompressible. Achieving results were reported as axial velocity, disturbance velocity, wall shear stress and the outcomes were compared with previously experimental and CFD computations. The analogy of axial velocity profiles shows that they are in acceptable compliance with the empirical data. As well as disturbance velocity and wall shear stresses anticipated by this new approach, part by part simulation, are reasonably valid with the acceptable experimental studies.
Keywords: Laminar-turbulent-relaminarization regimes, stenosis, part by part simulation, numerical analysis, new approach
