Effect of hydrostatic compression design parameters on the stability of the liquid film

1975 ◽  
Vol 11 (4) ◽  
pp. 322-325
Author(s):  
N. V. Peredrii
Keyword(s):  
Liquid Film ◽  
Hydrostatic Compression ◽  
Design Parameters ◽  
The Stability

Design of a wheeled wall climbing robot based on the performance of bio-inspired dry adhesive material

Robotica ◽  
2021 ◽  
pp. 1-14
Author(s):  
Hongkai Li ◽  
Xianfei Sun ◽  
Zishuo Chen ◽  
Lei Zhang ◽  
Hongchao Wang ◽  
...  
Keyword(s):  
Flat Surface ◽  
Thrust Force ◽  
Adhesion Force ◽  
Structure Design ◽  
Design Parameters ◽  
Climbing Robot ◽  
Adhesive Material ◽  
Ducted Fan ◽  
The Stability ◽  
Belt System

Abstract Inspired by gecko’s adhesive feet, a wheeled wall climbing robot is designed in this paper with the synchronized gears and belt system acting as the wheels by considering both motion efficiency and adhesive capability. Adhesion of wheels is obtained by the bio-inspired adhesive material wrapping on the outer surface of wheels. A ducted fan mounted on the back of the robot supplies thrust force for the adhesive material to generate normal and shear adhesion force whilemoving on vertical surfaces. Experimental verification of robot climbing on vertical flat surface was carried out. The stability and the effect of structure design parameters were analyzed.

THE STABILITY ANALYSIS OF HEAT TRANSFER IN SATURATED LIQUID FILM OF THE SPECIAL MATERIALS

2005 ◽  
Vol 19 (28n29) ◽  
pp. 1547-1550
Author(s):  
YOULIANG CHENG ◽  
XIN LI ◽  
ZHONGYAO FAN ◽  
BOFEN YING
Keyword(s):  
Heat Transfer ◽  
Differential Equation ◽  
Surface Tension ◽  
Stability Analysis ◽  
Liquid Film ◽  
Nonlinear Relationship ◽  
Saturated Liquid ◽  
Nonlinear Surface ◽  
Isothermal Wall ◽  
The Stability

Representing surface tension by nonlinear relationship on temperature, the boundary value problem of linear stability differential equation on small perturbation is derived. Under the condition of the isothermal wall the effects of nonlinear surface tension on stability of heat transfer in saturated liquid film of different liquid low boiling point gases are investigated as wall temperature is varied.

Investigation of sustainability of lubricated journal bearing under relevant design parameters

2018 ◽  
Vol 70 (4) ◽  
pp. 789-804 ◽  
Author(s):  
M.M. Shahin ◽  
Mohammad Asaduzzaman Chowdhury ◽  
Md. Arefin Kowser ◽  
Uttam Kumar Debnath ◽  
M.H. Monir
Keyword(s):  
Aspect Ratio ◽  
Elastic Strain ◽  
Journal Bearing ◽  
Design Parameters ◽  
Content Type ◽  
Computational Fluid Dynamics Cfd ◽  
Stress Formation ◽  
Bearing Design ◽  
The Stability ◽  
Bearing Friction

Purpose The purposes of the present study are to ensure higher sustainability of journal bearings under different applied loads and to observe bearing performances such as elastic strain, total deformation and stress formation. Design/methodology/approach A journal bearing test rig was used to determine the effect of the applied load on the bearing friction, film thickness, lubricant film pressure, etc. A steady-state analysis was performed to obtain the bearing performance. Findings An efficient aspect ratio (L/D) range was obtained to increase the durability or the stability of the bearing while the bearing is in the working condition by using SAE 5W-30 oil. The results from the study were compared with previous studies in which different types of oil and water, such as Newtonian fluid (NF), magnetorheological fluid (MRF) and nonmagnetorheological fluid (NMRF), were used as the lubricant. To ensure a preferable aspect ratio range (0.25-0.50), a computational fluid dynamics (CFD) analysis was conducted by ANSYS; the results show a lower elastic strain and deformation within the preferable aspect ratio (0.25-0.50) rather than a higher aspect ratio using the SAE 5W-30 oil. Originality/value It is expected that the findings of this study will contribute to the improvement of the bearing design and the bearing lubricating system.

Stability and collapse of holes in liquid layers

2018 ◽  
Vol 855 ◽  
pp. 1130-1155 ◽  
Author(s):  
Cunjing Lv ◽  
Michael Eigenbrod ◽  
Steffen Hardt
Keyword(s):  
Liquid Film ◽  
Power Laws ◽  
Theoretical Models ◽  
Liquid Volume ◽  
Capillary Length ◽  
Minimum Thickness ◽  
The Stability ◽  
Film Profile ◽  
Hole Closure ◽  
Good Agreement

We investigate experimentally and theoretically the stability and collapse of holes in liquid layers on bounded substrates with various wettabilities. It is shown that for a liquid layer with a thickness of the order of the capillary length, a stable hole exists when the hole diameter is bigger than a critical value $d_{c}$. Consequently, a further increase of the liquid volume causes the hole to collapse. It is found that$d_{c}$increases with the size of the container, but its dependence on the contact angle is very weak. The experimental results are compared with theory, and good agreement is obtained. Moreover, we present investigations of the dynamics of the hole and the evolution of the liquid film profile after the collapse. The diameter of the hole during collapse and the minimum thickness of the liquid film shortly after the collapse obey different power laws with time. Simple theoretical models are developed which indicate that the collapse of the hole is triggered by surface tension and the subsequent closure process results from inertia, whereas the growth of the liquid column after hole closure results from the balance between the capillary force and inertia. Corresponding scaling coefficients are determined.

scholarly journals Aeroelastic Behavior of Low Aspect Ratio Metal and Composite Blades

1986 ◽  
Author(s):  
James F. White ◽  
Oddvar O. Bendiksen
Keyword(s):  
Aspect Ratio ◽  
Opposite Effect ◽  
Design Parameters ◽  
Aeroelastic Stability ◽  
Low Aspect Ratio ◽  
Supersonic Flutter ◽  
Type Mode ◽  
The Stability ◽  
Composite Blades ◽  
Plate Type

The aeroelastic stability of titanium and composite blades of low aspect ratio is examined over a range of design parameters, using a Rayleigh-Ritz formulation. The blade modes include a plate-type mode to account for chordwise bending. Chordwise flexibility is found to have a significant effect on the unstalled supersonic flutter of low aspect ratio blades, and also on the stability of tip sections of shrouded fan blades. For blades with a thickness of less than approximately four percent of chord, the chordwise, second bending, and first torsion branches are all unstable at moderately high supersonic Mach numbers. For composite blades, the important structural coupling between bending and torsion cannot be modeled properly unless chordwise bending is accounted for. Typically, aft fiber sweep produces beneficial bending-torsion coupling that is stabilizing, whereas forward fiber sweep has the opposite effect. By using crossed-ply laminate configurations, critical aeroelastic modes can be stabilized.

Seismic stability analyses of reinforced tapered landfill cover systems considering seepage forces

2018 ◽  
Vol 36 (4) ◽  
pp. 361-372 ◽  
Author(s):  
Afshin Khoshand ◽  
Ali Fathi ◽  
Milad Zoghi ◽  
Hamidreza Kamalan
Keyword(s):  
Parametric Study ◽  
Limit Equilibrium ◽  
Practical Method ◽  
Seismic Stability ◽  
Design Parameters ◽  
Cover System ◽  
Landfill Cover ◽  
Cover Systems ◽  
Landfill Cover System ◽  
The Stability

One of the most common and economical methods for waste disposal is landfilling. The landfill cover system is one of the main components of landfills which prevents waste exposure to the environment by creating a barrier between the waste and the surrounding environment. The stability and integrity of the landfill cover system is a fundamental part of the design, construction, and maintenance of landfills. A reinforced tapered landfill cover system can be considered as a practical method for improving its stability; however, the simultaneous effects of seismic and seepage forces in the reinforced tapered landfill cover system have not been studied. The current paper provides a solution based on the limit equilibrium method in order to evaluate the stability of a reinforced tapered landfill cover system under seismic and seepage (both horizontal and parallel seepage force patterns) loading conditions. The proposed analytical approach is applied to different design cases through parametric study and the obtained results are compared to those derived from literature. Parametric study is performed to illustrate the sensitivity of the safety factor (FS) to the different design parameters. The obtained results reveal that parameters which describe the geometry have limited effects on the stability of the landfill cover system in comparison to the rest of the studied design parameters. Moreover, the comparisons between the derived results and available methods demonstrate good agreement between obtained findings with those reported in the literature.

scholarly journals The Stability of the Liquid Film

1942 ◽  
Vol 63 (6) ◽  
pp. 691-696 ◽  
Author(s):  
Jitsusaburo SAMESHIMA ◽  
Masaji NAKAMUTA ◽  
Ryoiti TERADA
Keyword(s):  
Liquid Film ◽  
The Stability

STABILITY ANALYSIS OF THE THIN POWER LAW LIQUID FILM FLOWING DOWN ON A VERTICAL CYLINDER

2006 ◽  
Vol 30 (1) ◽  
pp. 81-96 ◽  
Author(s):  
Po-Jen Cheng ◽  
Kuo-Chi Liu
Keyword(s):  
Liquid Film ◽  
Power Law ◽  
Film Flow ◽  
Vertical Cylinder ◽  
Flow Index ◽  
Free Film ◽  
Long Wave ◽  
Lateral Curvature ◽  
The Stability ◽  
Film Interface

The paper investigates the stability theory of a thin power law liquid film flowing down along the outside surface of a vertical cylinder. The long-wave perturbation method is employed to solve for generalized linear kinematic equations with free film interface. The normal mode approach is used to compute the stability solution for the film flow. The degree of instability in the film flow is further intensified by the lateral curvature of cylinder. This is somewhat different from that of the planar flow. The analysis results also indicate that by increasing the flow index and increasing the radius of the cylinder the film flow can become relatively more stable as traveling down along the vertical cylinder.

The Meniscus Instability of a Thin Liquid Film

1988 ◽  
Vol 55 (4) ◽  
pp. 975-980 ◽  
Author(s):  
H. Koguchi ◽  
M. Okada ◽  
K. Tamura
Keyword(s):  
Thin Film ◽  
Analytical Solution ◽  
Liquid Film ◽  
Tilt Angle ◽  
Stability Criterion ◽  
Thin Liquid Film ◽  
Normal Direction ◽  
Wave Number ◽  
The Stability ◽  
Maximum Amplification

This paper reports on the instability for the meniscus of a thin film of a very viscous liquid between two tilted plates, which are separated at a constant speed with a tilt angle in the normal direction of the plates. The disturbances on the meniscus moving with movement of the plates are examined experimentally and theoretically. The disturbances are started when the velocity of movement of the plates exceeds a critical one. The wavelength of the disturbances is measured by using a VTR. The instability of the meniscus is studied theoretically using the linearized perturbation method. A simple and complete analytical solution yields both a stability criterion and the wave number for a linear thickness geometry. These results compared with experiments for the instability show the validity of the stability criterion and the best agreement is obtained with the wave number of maximum amplification.

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