A Theoretical Model of Striated Film-Rupture Applied to the Cylinder-Plane

1985 ◽  
Vol 107 (3) ◽  
pp. 419-422 ◽  
Author(s):  
C. Fall
Keyword(s):  
Experimental Data ◽  
Theoretical Model ◽  
Perturbation Analysis ◽  
Reynolds Equation ◽  
Plane Geometry ◽  
Time Dependent ◽  
Linear Perturbation ◽  
Film Rupture ◽  
Successful Prediction

The author has previously presented a theoretical model of striated film-rupture consisting of a time-dependent linear perturbation analysis applied to the Reynolds equation. After review this model is applied to the cylinder-plane geometry for comparison with theoretical and experimental data due to Savage. Successful prediction of the number of striations for varying (ηU/T) and (R/h0) is achieved.

A Theoretical Model of Striated Film-Rupture

1982 ◽  
Vol 104 (2) ◽  
pp. 164-167 ◽  
Author(s):  
C. Fall
Keyword(s):  
Thin Film ◽  
Theoretical Model ◽  
Viscous Fluid ◽  
Perturbation Analysis ◽  
Time Dependent ◽  
Linear Perturbation ◽  
Film Rupture ◽  
Gap Width ◽  
Theory And Experiment ◽  
Good Agreement

In general, when a thin film of viscous fluid ruptures in the diverging region of flow between a spreader (or roller) and a flat plate, the cavity formed is not uniform, but appears as adjacent air fingers separated by streamers of fluid. A time-dependent linear perturbation analysis is used to examine the nature of such striated film-rupture and, specifically, to predict the number of striations per unit width for varying minimum gap width and the parameter (ηU/T). Good agreement between theory and experiment is obtained.

Inertia Effects on Film Rupture in Hydrodynamic Lubrication

1995 ◽  
Vol 117 (4) ◽  
pp. 685-690
Author(s):  
Terukazu Ota ◽  
Hiroyuki Yoshikawa ◽  
Makoto Hamasuna ◽  
Takeshi Motohashi ◽  
Soshu Oi
Keyword(s):  
Experimental Data ◽  
Boundary Condition ◽  
Reynolds Equation ◽  
Hydrodynamic Lubrication ◽  
Numerical Data ◽  
Wave Number ◽  
Film Rupture ◽  
Rupture Surface ◽  
Inertia Effects ◽  
Good Agreement

A perturbation analysis was made to study the effect of inertia on the film rupture in hydrodynamic lubrication using a modified Reynolds equation. A simplified boundary condition at film rupture proposed by Ota (1987) was employed. The theory was extended to investigate the wave number of the film rupture surface and to investigate the effect of gas bubbles included in the lubricant. Numerical calculations were carried out for a cylinder-plane bearing and are compared with previous experimental and numerical data. The effects of inertia on film rupture characteristics are clarified and the present numerical results are found to be in good agreement with earlier experimental data.

A Note on Film Rupture in Hydrodynamic Lubrication

1987 ◽  
Vol 109 (3) ◽  
pp. 562-566 ◽  
Author(s):  
Terukazu Ota
Keyword(s):  
Experimental Data ◽  
Boundary Condition ◽  
Experimental Study ◽  
Boundary Conditions ◽  
Present Model ◽  
Hydrodynamic Lubrication ◽  
Correction Term ◽  
Plane Geometry ◽  
Separation Boundary ◽  
Film Rupture

A theoretical and experimental study has been made for a film repture in hydrodynamic lubrication. A model is proposed on boundary conditions at the film rupture point. It contains a pressure correction term as a parameter, which simplifies that derived by Coyne and Elrod, and the so-called separation boundary condition. Some experiments have been conducted for a flow in a cylinder-plane geometry. It is found that numerical results using the present model agree reasonably well with the present and previous experimental data.

Surface Ribbing of a Thin Viscous Fluid Film Emerging From a Spreader or Roller

1978 ◽  
Vol 100 (4) ◽  
pp. 462-466 ◽  
Author(s):  
C. Fall
Keyword(s):  
Thin Film ◽  
Surface Tension ◽  
Viscous Fluid ◽  
Flat Plate ◽  
Perturbation Analysis ◽  
Linear Perturbation ◽  
Narrow Gap ◽  
Film Rupture ◽  
Characteristic Distance ◽  
Viscous Fluid Film

The thin film produced by the flow of a viscous fluid through a narrow gap between a spreader (or roller) and a flat plate is often subject to surface ribbing. A linear perturbation analysis, based upon lubrication theory, is used to examine the nature of this ribbed film and, specifically, to explain the large distances over which ribbing is observed to prevail. Taking into account the effects of both surface tension and gravity in smoothing out the film, the analysis predicts a characteristic distance from striated film-rupture to where a uniform film is formed.

Modal Analysis of the Axial Compressor Blade: Advanced Time-Dependent Electronic Interferometry and Finite Element Method

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Mykhaylo Tkach ◽  
Serhii Morhun ◽  
Yuri Zolotoy ◽  
Irina Zhuk
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Finite Element ◽  
High Reliability ◽  
Axial Compressor ◽  
Time Dependent ◽  
Experimental Setup ◽  
Vibration Modes ◽  
Compressor Blades ◽  
Isoparametric Finite Element

AbstractNatural frequencies and vibration modes of axial compressor blades are investigated. A refined mathematical model based on the usage of an eight-nodal curvilinear isoparametric finite element was applied. The verification of the model is carried out by finding the frequencies and vibration modes of a smooth cylindrical shell and comparing them with experimental data. A high-precision experimental setup based on an advanced method of time-dependent electronic interferometry was developed for this aim. Thus, the objective of the study is to verify the adequacy of the refined mathematical model by means of the advanced time-dependent electronic interferometry experimental method. The divergence of the results of frequency measurements between numerical calculations and experimental data does not exceed 5 % that indicates the adequacy and high reliability of the developed mathematical model. The developed mathematical model and experimental setup can be used later in the study of blades with more complex geometric and strength characteristics or in cases when the real boundary conditions or mechanical characteristics of material are uncertain.

scholarly journals Simple Algebraic Expressions for the Prediction and Control of High-Temperature Annealed Structures by Linear Perturbation Analysis

2021 ◽  
Vol 26 (2) ◽  
pp. 43
Author(s):  
Constantino Grau Grau Turuelo ◽  
Cornelia Breitkopf
Keyword(s):  
High Temperature ◽  
Surface Diffusion ◽  
Perturbation Analysis ◽  
Algebraic Model ◽  
Structure Design ◽  
Linear Perturbation ◽  
Prediction And Control ◽  
Void Shape ◽  
Void Structure ◽  
And Control

The prediction and control of the transformation of void structures with high-temperature processing is a critical area in many engineering applications. In this work, focused on the void shape evolution of silicon, a novel algebraic model for the calculation of final equilibrium structures from initial void cylindrical trenches, driven by surface diffusion, is introduced. This algebraic model provides a simple and fast way to calculate expressions to predict the final geometrical characteristics, based on linear perturbation analysis. The obtained results are similar to most compared literature data, especially, to those in which a final transformation is reached. Additionally, the model can be applied in any materials affected by the surface diffusion. With such a model, the calculation of void structure design points is greatly simplified not only in the semiconductors field but in other engineering fields where surface diffusion phenomenon is studied.

The Effect of Journal Bearing Misalignment on Load and Cavitation for Non-Newtonian Lubricants

1986 ◽  
Vol 108 (4) ◽  
pp. 645-654 ◽  
Author(s):  
R. H. Buckholz ◽  
J. F. Lin
Keyword(s):  
Reynolds Equation ◽  
Numerical Solutions ◽  
Journal Bearings ◽  
Surface Boundary ◽  
Film Rupture ◽  
Aspect Ratios ◽  
Free Surface Boundary Condition ◽  
Load Carrying ◽  
Boundary Location ◽  
Surface Boundary Condition

An analysis for hydrodynamic, non-Newtonian lubrication of misaligned journal bearings is given. The hydrodynamic load-carrying capacity for partial arc journal bearings lubricated by power-law, non-Newtonian fluids is calculated for small valves of the bearing aspect ratios. These results are compared with: numerical solutions to the non-Newtonian modified Reynolds equation, with Ocvirk’s experimental results for misaligned bearings, and with other numerical simulations. The cavitation (i.e., film rupture) boundary location is calculated using the Reynolds’ free-surface, boundary condition.

The structure of the Cincinnati arch as determined by short period Rayleigh waves

1969 ◽  
Vol 59 (1) ◽  
pp. 399-407
Author(s):  
Robert B. Herrmann
Keyword(s):  
Experimental Data ◽  
Theoretical Model ◽  
Layer Thickness ◽  
Rayleigh Waves ◽  
Layer Model ◽  
Depth Data ◽  
Short Period ◽  
Best Fitting ◽  
Good Agreement

Abstract The propagation of Rayleigh waves with periods of 0.4 to 2.0 seconds across the Cincinnati arch is investigated. The region of investigation includes southern Indiana and Ohio and northern Kentucky. The experimental data for all paths are fitted by a three-layer model of varying layer thickness but of fixed velocity in each layer. The resulting inferred structural picture is in good agreement with the known basement trends of the region. The velocities of the best fitting theoretical model agree well with velocity-depth data from a well in southern Indiana.

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