Steady and unsteady laminar flows of Newtonian and generalized Newtonian fluids in a planar T‐junction

Abstract

SUMMARYAn investigation of laminar steady and unsteady flows in a two-dimensional T-junction was carried out for Newtonian and a non-Newtonian fluid analogue to blood. The flow conditions considered are of relevance to hemodynamical applications and the localization of coronary diseases, and the main objective was to quantify the accuracy of the predictions and to provide benchmark data that are missing for this prototypical geometry. Under steady flow, calculations were performed for a wide range of Reynolds numbers and extraction flow rate ratios, and accurate data for the recirculation sizes were obtained and are tabulated. The two recirculation zones increased with Reynolds number, but the behaviour was non-monotonic with the flow rate ratio. For the pulsating flows a periodic instability was found, which manifests itself by the breakdown of the main vortex into two pieces and the subsequent advection of one of them, while the secondary vortex in the main duct was absent for a sixth of the oscillating period. Shear stress maxima were found on the walls opposite the recirculations, where the main fluid streams impinge onto the walls. For the blood analogue fluid, the recirculations were found to be 10% longer but also short lived than the corresponding Newtonian eddies, and the wall shear stresses are also significantly different especially in the branch duct.

A hybrid finite volume/finite element method for incompressible generalized Newtonian fluid flows on unstructured triangular meshes

“…(26) to Eq. (29) originally proposed by Rhie and Chow [4], which can efficiently eliminate the spurious pressure wiggles on collocated grids.…”

“…In the past years, Neofytou [24,25] used the SIMPLE method coupled with the QUICK scheme on collocated structured grids for generalized Newtonian fluid flows of Power-Law, Bingham, Quemada and Casson models. Miranda et al [26] employed the FVM in conjunction with SIMPLE on non-uniform structured grids for Newtonian and generalized Newtonian fluid flows in a planar T-junction. Tomé et al [27] developed an FVM method coupled with the SMAC method on staggerd structured grids to simulate the 2D generalized Newtonian free surfaces flow.…”

Assessment of a hydraulic network model for zig–zag cooled power transformer windings

“…The procedure to extract pressure drop data from CFD results closely follows the work by El-Shaboury et al [22], who focused on the heat transfer in 2D dividing T-junctions. The work of Miranda et al [23] also deals with 2D dividing T-junctions and details the process followed for the simulation.…”

Pressure Change in Tee Branch Pipe in Oscillatory Flow

“…Some modern studies [8][9][10][11] showed precise structure of pressure change in branch pipe or T-joint. Many of these studies, however, considered flow of liquid.…”