Fluid Inertia Effects in a Squeeze Film Between Two Plane Annuli

1984 ◽  
Vol 106 (2) ◽  
pp. 223-227 ◽  
Author(s):  
A. F. Elkouh
Keyword(s):  
Power Series ◽  
Load Capacity ◽  
Equations Of Motion ◽  
Squeeze Film ◽  
Squeezing Flow ◽  
Series Expansions ◽  
Fluid Inertia ◽  
Inertia Effects ◽  
Flow Parameters ◽  
Power Series Expansions

An analysis is presented for the laminar squeezing flow of a Newtonian in-compressible fluid between parallel plane annuli. Both local and convective inertia of the flow are considered in the analysis. Power series expansions in terms of pertinent flow parameters are used to obtain a solution of the equations of motion. Expressions for the pressure and load capacity are presented, and compared with those based on the assumption of inertialess flow.

The Effect of Fluid Inertia in Squeeze Film Damper Bearings: A Heuristic and Physical Description

1983 ◽  
Author(s):  
John A. Tichy
Keyword(s):  
Hydrodynamic Lubrication ◽  
Turbulence Models ◽  
Squeeze Film ◽  
Squeezing Flow ◽  
Fluid Inertia ◽  
Inertia Effects ◽  
Practical Applications ◽  
Viscous Forces ◽  
Squeeze Film Dampers ◽  
Inertia Forces

Fluid inertia forces are comparable to viscous forces in squeeze film dampers in the range of many practical applications. This statement appears to contradict the commonly held view in hydrodynamic lubrication that inertia effects are small. Upon closer inspection, the latter is true for predominantly sliding (rather than squeezing) flow bearings. The basic equations of hydrodynamic lubrication flow are developed, including the inertia terms. The appropriate orders of magnitude of the viscous and inertia terms are evaluated and compared, for journal bearings and for squeeze film dampers. Exact equations for various limiting cases are presented: low eccentricity, high and low Reynolds number. The asymptotic behavior is surprisingly similar in all cases. Due to inertia, the damper force may shift 90° forward from its purely viscous location. Inertia forces are evaluated for typical damper conditions. The effect of turbulence in squeeze film dampers is also discussed. On physical grounds it is argued that the transition occurs at much higher Reynolds numbers than the usual lubrication turbulence models predict.

Fluid Inertia Effects in Non-Newtonian Squeeze Films

1976 ◽  
Vol 98 (3) ◽  
pp. 409-411 ◽  
Author(s):  
A. F. Elkouh
Keyword(s):  
Load Capacity ◽  
Squeeze Film ◽  
Energy Integral ◽  
Fluid Inertia ◽  
Inertia Effects ◽  
First Order ◽  
Integral Methods ◽  
Method Yield ◽  
Pseudoplastic Fluids ◽  
Good Agreement

The momentum and energy integral methods are used to study the effect of inertia on the behavior of a non-Newtonian (Power Law) squeeze film. It is shown that the inertia correction in the load capacity is more significant for pseudoplastic fluids, n < 1. For a Newtonian fluid, n = 1, the expressions obtained by using the energy integral method yield results identical to those obtained from a first-order iteration, and which are in good agreement with available experiments.

Non-Newtonian Squeeze Film Between Two Plane Annuli

1982 ◽  
Vol 104 (2) ◽  
pp. 275-278 ◽  
Author(s):  
A. F. Elkouh ◽  
N. J. Nigro ◽  
Y. S. Liou
Keyword(s):  
Thin Film ◽  
Power Law ◽  
Load Capacity ◽  
Parallel Plane ◽  
Squeeze Film ◽  
Squeezing Flow ◽  
Fluid Inertia ◽  
Power Law Fluid ◽  
Analytic Expressions ◽  
Time Relation

An analysis is presented for the laminar squeezing flow of an incompressible power-law fluid between parallel plane annuli. The results obtained are based on the thin-film approximation, and negligible fluid-inertia. Analytic expressions for the load capacity of the squeeze film and its thickness-time relation are presented.

Non-Newtonian Inertia Squeeze Film Characteristics in Rectangular Stepped Plates

2015 ◽  
Vol 775 ◽  
pp. 73-77
Author(s):  
Jaw Ren Lin ◽  
Shu Ting Hu
Keyword(s):  
Normal Load ◽  
Load Capacity ◽  
Continuum Theory ◽  
Squeeze Film ◽  
Fluid Inertia ◽  
Inertia Effects ◽  
Lubrication Equation ◽  
Momentum Integral ◽  
Film Characteristics ◽  
Inertia Forces

A study of non-Newtonian inertia squeeze film in rectangular stepped plates has been presented in this paper. Applying the momentum integral method incorporating the micro-continuum theory of non-Newtonian fluids, a non-Newtonian inertia lubrication equation is derived. It is found that the fluid inertia effects yield in a higher normal load capacity as well as a longer squeeze film time as compared to the non-Newtonian stepped squeeze film in the absence of fluid inertia forces.

Investigation of the Squeeze Film Dynamics Underneath a Microstructure With Large Oscillation Amplitudes and Inertia Effects

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Nadim A. Diab ◽  
Issam A. Lakkis
Keyword(s):  
Rarefied Gas ◽  
Direct Simulation Monte Carlo ◽  
Squeeze Film ◽  
Dsmc Method ◽  
Inertia Effects ◽  
Flow Parameters ◽  
Fluid Behavior ◽  
Dimensionless Groups ◽  
Simulation Monte Carlo ◽  
The Impact

This paper presents direct simulation Monte Carlo (DSMC) numerical investigation of the dynamic behavior of a gas film in a microbeam. The microbeam undergoes large amplitude harmonic motion between its equilibrium position and the fixed substrate underneath. Unlike previous work in literature, the beam undergoes large displacements throughout the film gap thickness and the behavior of the gas film along with its impact on the moving microstructure (force exerted by gas on the beam's front and back faces) is discussed. Since the gas film thickness is of the order of few microns (i.e., 0.01 < Kn < 1), the rarefied gas exists in the noncontinuum regime and, as such, the DSMC method is used to simulate the fluid behavior. The impact of the squeeze film on the beam is investigated over a range of frequencies and velocity amplitudes, corresponding to ranges of dimensionless flow parameters such as the Reynolds, Strouhal, and Mach numbers on the gas film behavior. Moreover, the behavior of compressibility pressure waves as a function of these dimensionless groups is discussed for different simulation case studies.

scholarly journals Parallel Software to Offset the Cost of Higher Precision

2021 ◽  
Vol 40 (2) ◽  
pp. 59-64
Author(s):  
Jan Verschelde
Keyword(s):  
Power Series ◽  
Parallel Algorithms ◽  
Series Expansions ◽  
Use Case ◽  
Double Precision ◽  
Algebraic Space ◽  
Space Curves ◽  
Computational Overhead ◽  
Power Series Expansions ◽  
The Cost

Hardware double precision is often insufficient to solve large scientific problems accurately. Computing in higher precision defined by software causes significant computational overhead. The application of parallel algorithms compensates for this overhead. Newton's method to develop power series expansions of algebraic space curves is the use case for this application.

Dynamic Characterization of an Integral Squeeze Film Bearing Support Damper for a Supercritical CO2 Expander

2017 ◽  
Author(s):  
Bugra Ertas ◽  
Adolfo Delgado ◽  
Jeffrey Moore
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
Mechanical Impedance ◽  
Squeeze Film ◽  
Fluid Inertia ◽  
Inertia Effects ◽  
Damping Behavior ◽  
Impedance Testing ◽  
Stiffness And Damping ◽  
Onset Of Cavitation

The present work advances experimental results and analytical predictions on the dynamic performance of an integral squeeze film damper (ISFD) for application in a high-speed super-critical CO2 (sCO2) expander. The test campaign focused on conducting controlled orbital motion mechanical impedance testing aimed at extracting stiffness and damping coefficients for varying end seal clearances, excitation frequencies, and vibration amplitudes. In addition to the measurement of stiffness and damping; the testing revealed the onset of cavitation for the ISFD. Results show damping behavior that is constant with vibratory velocity for each end seal clearance case until the onset of cavitation/air ingestion, while the direct stiffness measurement was shown to be linear. Measurable added inertia coefficients were also identified. The predictive model uses an isothermal finite element method to solve for dynamic pressures for an incompressible fluid using a modified Reynolds equation accounting for fluid inertia effects. The predictions revealed good correlation for experimentally measured direct damping, but resulted in grossly overpredicted inertia coefficients when compared to experiments.

Annular Squeeze Films With Inertial Effects

1983 ◽  
Vol 105 (3) ◽  
pp. 361-363 ◽  
Author(s):  
S. R. Turns
Keyword(s):  
Annular Plate ◽  
Equation Of Motion ◽  
Plate Motion ◽  
Squeezing Flow ◽  
Approximation Technique ◽  
Inertial Effects ◽  
Fluid Inertia ◽  
Governing Equations ◽  
Inertia Effects ◽  
Incompressible Newtonian Fluid

An analysis of the laminar squeezing flow of an incompressible Newtonian fluid between parallel plane annuli is presented in which a successive approximation technique is used to account for fluid inertia effects. An expression for the force generated by the fluid is developed and coupled to the equation of motion for the annular plate. Results are presented from the numerical integration of the governing equations for the plate motion.

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