The stability of the incompressible boundary layer in the axial flow past a cylinder has not been studied a great deal. The laminar flow is shown here to be always stable at high transverse curvatures to linear as well as secondary disturbances. At low levels of curvature, the first instability is delayed, but several non-axisymmetric modes are simultaneously unstable, which could lead to a dif...

Matched asymptotic solutions for the steady banded flow of the diffusive Johnson-Segalman model in various geometries ⋆ Abstract We present analytic solutions for steady flow of the Johnson-Segalman (JS) model with a diffusion term in various geometries and under controlled strain rate conditions , using matched asymptotic expansions. The diffusion term represents a singular perturbation that l...

One of the problems that sometimes occur in gas allocation optimization is instability phenomenon. This phenomenon reduces the oil production and damages downhole and surface facilities. Different works have studied the stability and suggested some solutions to override it, but most of them (such as making the well intelligent) are very expensive and thus they are not applicable to many cases. ...

Article history: Received 28 February 2008 Received in revised form 19 September 2008 Accepted 15 November 2008 Available online 27 November 2008

We report experimental and numerical results from investigations into the onset of novel localized cellular states in the centrifugally stable regime of Taylor–Couette flow at sufficiently high rates of counter-rotation of the outer cylinder. Quantitative comparison is made between experimental results and those obtained from numerical bifurcation studies of the steady axisymmetric Navier– Stok...

The effects of inhaled stable xenon gas on cerebral blood flow were studied with 23 transcranial Doppler examinations performed in 13 normal volunteers while breathing, 25, 30, or 35% xenon for 5 min. Doppler velocities from the middle cerebral artery rose significantly during inhalation in 85% of subjects and 78% of studies and decreased significantly in 15% of subjects and 17% of studies. The...

Free convection between two interconnected reservoirs, due to density differences maintained by heat and salt transfer to the reservoirs, is shown to occur sometimes in two different stable regimes, and may possibly be analogous to certain features of the oseanic circulation. The density of sea-water is modified while at the surface by two distinct processes: heating and cooling, which change t...

ABSTRACT: Mayonnaise is probably one of the most widely used sauces worldwide. The oil content of traditionally mayonnaise is more than 65%. Fat has a role in creating viscosity, color and texture but might cause many diseases and disorders in human. In this study the influence of modified wheat bran as a fat replacer on the rheological properties of low fat mayonnaise was studied and compared ...

OBJECTIVE To assess the impact of respiratory therapy with the expiratory flow increase technique on cerebral hemodynamics of premature newborns. METHODS This is an intervention study, which included 40 preterm infants (≤34 weeks) aged 8-15 days of life, clinically stable in ambient air or oxygen catheter use. Children with heart defects, diagnosis of brain lesion and/or those using vasoactiv...

The author proposes a flow control scheme which derives the optimal packet transmission rate from the ACKs of the sending packets. The optimization is based on mathematical programming such as the extremal method and leastsquares method. The author proves that the proposed method is fair when the RTT and thepacket length of each sender are the same. It is also shown that the sufficient conditio...