We study the motion of large bubbles in curved channels both semi-analytically using the lubrication approximation and computationally using a finite-volume/fronttracking method. The steady film thickness is governed by the classical Landau– Levich–Derjaguin–Bretherton (LLDB) equation in the low-capillary-number limit but with the boundary conditions modified to account for the channel curvatur...

Petal gas bearings are widely used in industrial turbine installations. However, there practically no mathematical models that take into account the nonlinear dependence of elastic element deformations gas-dynamic bearing on pressure. It is very difficult to obtain a converged solution with given accuracy an acceptable time. On this basis, model motion petals package was proposed. The takes pre...

In the current study, 5-nydroxytryptamine (5-HT) and gastrin (GAS) cells in the digestive canals of Rana chensinensis tadpoles at different developmental stages were investigated by immunohistochemistry. Results showed that the 5-HT cells were only detected in the duodenum before metamorphosis began, and were extensively distributed in the stomach, duodenum, small intestine, and rectum thereaft...

OBJECTIVE To compare equine synovial fluid (SF) from injured and control joints for cartilage boundary lubrication function; concentrations of the putative boundary lubricant molecules hyaluronan (HA), proteoglycan 4 (PRG4), and surface-active phospholipids (SAPLs); relationships between lubrication function and composition; and lubrication restoration by addition of HA. METHODS Equine SF fro...

The lubrication system of an internal combustion engine serves many purposes. It lubricates moving parts, cools the engine, removes impurities, supports loads, and minimizes friction. The entrapment of air in the lubricating oil is called oil aeration. Oil aeration can be detrimental to internal combustion (IC) engines. This study attempts to determine a means to reduce the level of aeration in...

We review some of the key tribological issues of relevance to motorsport applications. Tribology is the science of friction and wear, and in a high performance engine, friction and wear are controlled by good component design (e.g. the engine and the transmission) and also by the use of high performance lubricants with the correct physical (and chemical) properties, matched to the machine they ...

Thin fluid films can have surprising behavior depending on the boundary conditions enforced, the energy input and the specific Reynolds number of the fluid motion. Here we study the equations of motion for a thin fluid film with a free boundary and its other interface in contact with a solid wall. Although shear dissipation increases for thinner layers and the motion can generally be described ...

A generalized form of Reynolds equation for fluid lubrication has been derived considering the effects of viscosity variation in the film and slip at the bearing surfaces. Various specific cases have been deduced and the concept of multiple-layer lubrication introduced. The higher lubricant viscosity near the bearing surface is beneficial in reducing the coefficient of friction but the effect o...