Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 39 for “"lubrication theory"”.
-
Compressible Lubrication Theory in Pressurized Gases
Lubrication theory plays a fundamental role in all mechanical design as well as applications to biomechanics. All machinery are composed of moving parts which must be protected against wear and damage. Without effective lubrication, maintenance cycles will be shortened to impractical levels …
-
Stability analysis of a bilayer contained within a cylindrical tube
… concentration is derived by using an extended lubrication theory analysis. A linear stability study using normal modes is conducted by linearizing the nonlinear evolution equations. A linear eigenvalue problem for the perturbation amplitudes is obtained. Non-trivial solutions are obtained …
-
Surface and Hydrodynamic Forces in Wetting Films
… in the present work on the basis of the Reynolds lubrication theory. The technique has been used to study the effects of surface hydrophobicity, electrolyte (Al3+ ions) concentration, and bubble size on the stability of wetting films. Further, the geometric mean combining rule has been tested to …
-
Influencing contact-line behavior in dynamic wetting through thermocapillarity and surface topography
… in industrial processes. In the second part, a lubrication-theory-based model is developed to study the motion of droplets of a Newtonian liquid on substrates with topographical defects due to pressure-driven flow of a surrounding fluid. Above a critical pressure gradient, the shear force acting …
-
Investigation of the tensile strength of liquid squeeze-films subjected to oscillating normal loads
… An analysis was developed based on Reynolds lubrication theory and predicted accurately the basic trends of the data.
-
Rotordynamic analysis of circumferentially grooved annular pump seals with turbulent flow and inlet swirl
… groove is modelled using turbulent shear layer theory and an entrance loss model is applied at the inlet and land regions of the seal. The governing equations are derived using Hirs’ turbulent lubrication theory. The equations are expanded to yield zeroth and first order perturbation equations …
-
On a Cartesian cut-cell methodology for simulating atmospheric ice accretion on aircraft
… Presently, the most advanced model is based on lubrication theory, however, linear terms are truncated. We extend the series expansion to include first order terms and demonstrate that the additional order is necessary to accurately capture the thin film flow on a cylinder. Furthermore, we …
-
Flow in thin regions bounded by structured and porous surfaces : applications to load bearings
… verified using a verification problem. Reynolds lubrication theory, derived from thin-region approximations of the Navier-Stokes equations, is used as the main tool for this study. The performance of a rough slider bearing is compared with a corresponding smooth slider bearing. The presence of …
-
Quantifying particle sorting in microbubble streaming flows
… experiment. It is also shown that an asymptotic theory that incorporates the device geometry and superimposed channel flow accurately models key flow features such as peak speeds and particle trajectories. Finally, the forces acting on particles on oscillatory time scales are determined …
-
Stability of rigid and deformable roll coating flows
… roll coater. The base state is modelled using lubrication theory and the flow domain is terminated with simple boundary conditions. It is found that the form of the meniscus location solutions differ from those found in similax flows by previous workers and this motivates a detailed …
-
Viscous fingering instabilities and gravity currents.–—
… a general moving front within the framework of lubrication theory is established by considering the asymptotic limit of large azimuthal wavenumber. Miscible intrusions in a Hele-Shaw cell with negligible diffusion are known to form flat frontal shocks for a sufficiently viscous ambient fluid. …
-
High-Frame-Rate Oil Film Interferometry
… of change of the height of the oil film using lubrication theory. The height of the oil film was determined from the high speed camera interferogram images using a MATLAB script which determined fringe spacing by fitting a four-parameter sine wave to the intensity levels in each image. The …
-
Thin fluid films subject to external airflows
We use lubrication theory to analyse the steady flow of thin ridges, rivulets and rings of fluid and, in particular, we study the behaviour when the fluid is in the presence of an external airflow. Firstly, a thin ridge on an inclined planar substrate subject to a spatially varying pressure …
-
Filler effects in resole adhesive formulations
… develop an adhesive tack measurement based upon lubrication theory. In this work, the probe-tack test was adapted to a typical stress-controlled rheometer by using the normal force and displacement system to compress the adhesive between parallel plates. By employing a simple power law to …
-
Computer simulation of the steady-state thermodynamic processes and piston ring wear for a multi-stage intercooled reciprocating air compressor
… pack are determined on the basis of hydrodynamic lubrication theory. The wear of the piston rings is assumed to occur when the hydrodynamic oil film between the piston ring and cylinder bore breaks down. Based on the theoretical model, a computer program is developed. This program is tested on an …
-
Novel Bioinspired Pumping Models for Microscale Flow Transport
… derived theoretical analysis is based on both lubrication theory and quasi-steady approximations at low Reynolds numbers. The meshfree numerical method is based on the method of fundamental solutions (MFS) that uses a set of singularized force elements ``Stokeslets'' to induce the flow motions. …
-
Hydrophobic Forces in Wetting Films
… the rupture of the wetting films using the DLVO theory. In the present work, we have measured the kinetics of film thinning between air bubble and flat surfaces of gold and silica. The former was hydrophobized by ex-site potassium amyl xanthate, while the latter by in-site …
-
Partial singular integro-differential equations models for dryout in boilers
… is proposed. The model is based on thin-layer lubrication theory and thin aerofoil theory. The exchange of mass between the vapour core and the liquid film due to evaporation of the liquid film is accounted for in the model. The mass exchange rate depends on the details of the flow conditions …
-
Several applications of a model for dense granular flows
… separated by a viscous fluid. Although classical lubrication theory suggests that two locally smooth objects converging under gravity will make contact only after infinite time, we discuss several physical effects that may promote contact in finite time. Detailed calculations are presented to …
Page 1 of 2