The conditions sufficient to ensure positivity and linearity preservation for a cell-centered finite volume scheme for time-dependent hyperbolic equations using irregular one-dimensional and triangular two-dimensional meshes are derived. The conditions require standard flux limiters to be modified and also involve possible constraints on the meshes. The accuracy of this finite volume scheme is ...

Two-dimensional Euler equations have been solved on an unstructured grid. An upwind finite volume scheme, based on Roe's flux difference splitting method, is used to discretize the equations. Using advancing front method, an initial Delaunay triangulation has been made. The adaptation procedure involves mesh enrichment coarsening in regions of flow with high low gradients of flow properties, ac...

in this paper, turbulent mixed convective heat transfer of water and al2o3 nanofluid has been numerically studied in a horizontal tube under non-uniform heat flux on the upper wall and insulation in the lower wall using mixture model. for the discretization of governing equations, the second-order upstream difference scheme and finite volume method were used. the coupling of pressure and veloci...

In this paper, the Al2O3-water nanofluid flow in laminar and turbulent flows inside tubes fitted with diamond-shaped turbulators is numerically modeled. The nanofluid flow is modeled by employing a two-phase mixture method and applying the constant heat flux boundary condition at tube walls. In the results, the effects of different parameters such as the geometry of turbulators, volume fraction...

results the mean kt/v was 1.27 ± 0.28 in high-flux and 1.10 ± 0.32 in low-flux membrane which, these differences were statistically significant (p = 0.017). the mean of urr was 0.65 ± 0.09 in high-flux and 0.61 ± 0.14 in low-flux membrane, which these differences were not statistically significant (p = 0.221). patients and methods forty hemodialysis patients participated in this cross-over clin...