Fluid flow and heat transfer of viscoelastic materials in noncircular duct are complicated subject because of nonlinear behavior of rheological properties. In this paper flow and heat transfer of CEF fluids are studied with numerical modeling. Numerical solution is based on the artificial compressibility method and by using staggered mesh. The effect of secondary flows on the forced and natural...

When a hot body A is thermally connected to a cold body B, the textbook knowledge is that heat flows from A to B. Here, we describe the opposite case in which heat flows from a colder but constantly heated body B to a hotter but constantly cooled body A through a two-phase liquid-vapor system. Specifically, we provide experimental evidence that heat flows through liquid and vapor phases of cryo...

Theoretical studies usually attribute convections to the developments of instabilities such as the static or symmetric instabilities of the basic flows. However, the following three facts make the validities of these basic theories unconvincing. First, it seems that in most cases the basic flow with balance property cannot exist as the exact solution, so one cannot formulate appropriate problem...

In this work, we consider an optimal control problem for a generalized model bioconvective flows, which are convection flows caused by the differences in concentration of upward swimming microorganisms fluid. We firstly study existence weak solutions mathematical fluid model; then prove controls and obtain corresponding first order optimality conditions using Dubovitskii-Milyutin formalism.

Rayleigh-Bénard convection in rotating spherical shells can be considered as a simplified analogue of many astrophysical and geophysical fluid flows. Here, we use threedimensional direct numerical simulations to study this physical process. We construct a dataset of more than 200 numerical models that cover a broad parameter range with Ekman numbers spanning 3 × 10−7 ≤ E ≤ 10−1, Rayleigh number...

Abs t r ac t . Recent developments concerning the connection between notions of hydrodynamic stability usually associated with stationary laminar flows-and dynamics, most notably turbulent fluid flows, are reviewed. Based on a technical device originally introduced by Hopf in 1941, a rigorous mathematical relationship between criteria for nonlinear energy stability and bounds on global t ranspo...

The numerical simulation of the interaction between a free surface flow and a moving obstacle is considered for the analysis of hydroplaning flows. A new augmented Lagrangian method, coupled to fictitious domains and penalty methods, is proposed for the simulation of multiphase flows. The augmented Lagrangian parameter is estimated by an automatic analysis of the discretization matrix resulting...

Context: A visualization of three-dimensional incompressible flows by divergence-free quasitwo-dimensional projections of velocity field on three coordinate planes is proposed. Objective: To visualize 3D incompressible flow by 3 two-dimensional plots. Method: It is argued that such divergence-free projections satisfying all the velocity boundary conditions are unique for a given velocity field....