In a turbulent boundary layer over a smooth flat plate with zero pressure gradient, the intermediate structure between the viscous sublayer and the free stream consists of two layers: one adjacent to the viscous sublayer and one adjacent to the free stream. When the level of turbulence in the free stream is low, the boundary between the two layers is sharp, and both have a self-similar structur...

Numerical computations and order-of-magnitude estimates are used to analyze a jet of a very viscous liquid of finite electrical conductivity that is injected at a constant flow rate in an immiscible dielectric liquid under the action of an electric field. The conditions under which the injected liquid can form an elongated meniscus with a thin jet issuing from its apex (a cone-jet) are investig...

Following Prandtl, a viscous-inviscid interaction (VII) method is presented, where the flow field is divided into a viscous shear layer and an inviscid outer region. Their coupling is performed with the quasi-simultaneous approach, making use of an appropriately chosen interaction law. Firstly, an engineering example of transonic airfoil flow is presented, in which the interaction law is based ...

Instantaneous velocity fields in the x-y plane of a zero pressure gradient turbulent boundary layer are measured using particle image velocimetry. It is found that there exist random, time-varying zones in the U-V fields in which the streamwise momentum is remarkably uniform. The largest dimension of a typical zone is proportional to the boundary layer thickness. The zone closest to the wall co...

The displacement of a more viscous fluid by a less viscous one in a quasi-two dimensional geometry leads to the formation of complex fingering patterns. This fingering has been characterized by a most unstable wavelength, λc, which depends on the viscosity difference between two immiscible fluids and sets the characteristic width of the fingers. How the finger length grows after the instability...

We study high order convergence of vanishing viscosity approximation to scalar hyperbolic conservation laws in one space dimension. We prove that, under suitable assumptions, in the region where the solution is smooth, the viscous solution admits an expansion in powers of the viscosity parameter ε. This allows an extrapolation procedure that yields high order approximation to the non-viscous li...

The tip-clearance flow in axial turbomachines is studied using large-eddy simulation with particular emphasis on understanding the underlying mechanisms for viscous losses in the end-wall region and the unsteady characteristics of the tipleakage vortical structures. Systematic and detailed analysis of the mean flow field and turbulence statistics has been made in a linear cascade with a moving ...

the paper numerically presents laminar forced convection of a nanofluid flowing in a duct at microscale. results were compared with both analytical and experimental data and observed good concordance with previous studies available in the literature. influences of brinkman and reynolds number on thermal and hydrodynamic indexes have been investigated. for a given nanofluid, no change in efficie...

Singularities in the dark energy universe are discussed, assuming that there is a bulk viscosity in the cosmic fluid. In particular, it is shown how the physically natural assumption of letting the bulk viscosity be proportional to the scalar expansion in a spatially flat FRW universe can drive the fluid into the phantom region (w < −1), even if lies in the quintessence region (w > −1) in the n...