Maxwell’s original slip boundary condition is widely misapplied in current rarefied gas flow calculations (e.g. in hypersonics, microfluidics). If its commonly-accepted form is applied in simulations of gas flows over curved or moving surfaces, crucial physics can be lost. We give examples of such cases. We also propose a new higher-order boundary condition which is based on Maxwell’s original ...

In this paper, uniqueness and uniform structural stability of Poiseuille flows in an infinitely long pipe with Navier boundary conditions are established for axisymmetric solutions steady Navier-Stokes system. This is a key step to study general Leray problem nozzle. The crucial point that the estimate respect both flux friction coefficient which appeared conditions. With aid special structure ...

We present an efficient and accurate immersed boundary (IB) finite element (FE) method for numerically solving the incompressible Navier–Stokes equations. Particular emphasis is given to internal flows with complex geometries (blood flow in vasculature system). IB methods are computationally costly flows, mainly due large percentage of grid points that lie outside domain. In this study, we appl...

The threshold amplitude for subcritical transition in Poiseuille and Couette ows is investigated. For Poiseuille ow we present examples where the threshold scales like R ?7=4 for 1500 R 5000, where R is the Reynolds number. For Couette ow we present an example where the threshold scales like R ?5=4 for 500 R 2000.

Motivated by the need for a theoretical study in a planar geometry that can easily be implemented experimentally, we study the pressure driven Poiseuille flow of a shear banding fluid. After discussing the “basic states” predicted by a one dimensional calculation that assumes a flat interface between the bands, we proceed to demonstrate such an interface to be unstable with respect to the growt...

This work is devoted to the study of the stability of Hagen–Poiseuille flow or pipe flow. The analysis is focused on the streak breakdown process by which two-dimensional streamwise-independent finite amplitude perturbations transiently modulate the basic flow leading to a profile that contains saddle points and is linearly unstable with respect to very small streamwise-dependent perturbations....

The paper announces a family of exact solutions to Navier–Stokes equations describing gradient inhomogeneous unidirectional fluid motions (nonuniform Poiseuille flows). structure the motion is such that incompressibility equation enables us establish velocity defect law for nonuniform flow. In this case, field dependent on two coordinates and time, it an arbitrary-degree polynomial relative hor...

Flow over micro-scale airfoils is investigated in order to understand the aerodynamic issues related to micro air vehicle design and performance. Studies have shown that such low Reynolds number flow exhibits rarefied phenomena and a flat plate having a thickness ratio of 5% has better aerodynamic performance than conventional streamlined airfoils. This paper simulates gas flows over a 5% flat ...

Electro-osmosis is the flow produced by the action of an electric field on a fluid with a net charge, which is created by the Zeta potential and confined in the Debye layer. This basic phenomenon in the electro-kinetic transport plays an important role in the microfluidic systems being explored today because it can be applied to a variety of MEMS devices. This paper presents global and point-wi...