scholarly journals The motion of curling rocks: Experimental investigation and semi-phenomenological description

2004 ◽  
Vol 82 (10) ◽  
pp. 791-809 ◽  
Author(s):  
E T Jensen ◽  
Mark RA Shegelski
Keyword(s):  
Experimental Investigation ◽  
Liquid Film ◽  
Frictional Force ◽  
Dry Friction ◽  
Thin Liquid Film ◽  
Ice Surface ◽  
Wet Friction ◽  
Wide Range ◽  
Friction Models ◽  
Rule Out

A large number of curling shots using a wide range of rotational and translational velocities on two different ice surfaces have been recorded and analyzed. The observed curling-rock trajectories are described in terms of a semi-phenomenological model. The data are found to rule out "dry-friction" models for the observed motion, and to support the idea that the curling rock rides upon a thin liquid film created at the ice surface (i.e., "wet friction"). Evidence is found to support the hypothesis that the frictional force acting upon each segment of the curling rock is directed opposite to the motion relative to this thin liquid film and not relative to the underlying fixed ice surface. PACS No.: 01.80.+b

The motion of a curling rock

1996 ◽  
Vol 74 (9-10) ◽  
pp. 663-670 ◽  
Author(s):  
Mark R. A. Shegelski ◽  
Ross Niebergall ◽  
Mark A. Walton
Keyword(s):  
Thin Film ◽  
Liquid Film ◽  
Physical Model ◽  
Liquid Water ◽  
Dry Friction ◽  
Thin Liquid Film ◽  
Kinetic Friction ◽  
Contact Areas ◽  
Wet Friction

We present a plausible physical model that accounts for the motion of a curling rock. The principal features of the model are (i) that the kinetic friction induces melting of the ice with the consequence that the curling rock experiences both "dry friction," when encountering solid ice, as well as "wet friction," for contact areas that pass over the thin film of liquid water lying above the ice; (ii) that the wet friction is velocity dependent; and (iii) that the curling rock is able, in its last stages of motion, to drag some of the thin liquid film part way around the rock, which significantly enhances the curl of the rock. We compare the model to actual trajectories of curling rocks.

scholarly journals Modeling of Partially Wetting Liquid Film Using an Enhanced Thin Film Model for Aero-Engine Bearing Chamber Applications

2021 ◽  
Vol 143 (4) ◽  
Author(s):  
Kuldeep Singh ◽  
Medhat Sharabi ◽  
Richard Jefferson-Loveday ◽  
Stephen Ambrose ◽  
Carol Eastwick ◽  
...  
Keyword(s):  
Thin Film ◽  
Contact Angle ◽  
Film Thickness ◽  
Liquid Film ◽  
Thin Liquid Film ◽  
Operating Conditions ◽  
Film Model ◽  
Thin Film Model ◽  
Wide Range ◽  
Aero Engine

Abstract In the case of aero-engine, thin lubricating film servers dual purpose of lubrication and cooling. Prediction of dry patches or lubricant starved region in bearing or bearing chambers are required for safe operation of these components. In this work, thin liquid film flow is numerically investigated using the framework of the Eulerian thin film model (ETFM) for conditions, which exhibit partial wetting phenomenon. This model includes a parameter that requires adjustment to account for the dynamic contact angle. Two different experimental data sets have been used for comparisons against simulations, which cover a wide range of operating conditions including varying the flowrate, inclination angle, contact angle, and liquid–gas surface tension coefficient. A new expression for the model parameter has been proposed and calibrated based on the simulated cases. This is employed to predict film thickness on a bearing chamber which is subjected to a complex multiphase flow. From this study, it is observed that the proposed approach shows good quantitative comparisons of the film thickness of flow down an inclined plate and for the representative bearing chamber. A comparison of model predictions with and without wetting and drying capabilities is also presented on the bearing chamber for shaft speed in the range of 2500 RPM to 10,000 RPM and flowrate in the range of 0.5 liter per minute (LPM) to 2.5 LPM.

scholarly journals The Motion of Rapidly Rotating Curling Rocks

1999 ◽  
Vol 52 (6) ◽  
pp. 1025 ◽  
Author(s):  
Mark R. A. Shegelski ◽  
Ross Niebergall
Keyword(s):  
Liquid Film ◽  
Relative Velocity ◽  
Thin Liquid Film ◽  
Translational Motion ◽  
Slow Rotation ◽  
Kinetic Friction ◽  
Centre Of Mass ◽  
Ice Surface ◽  
Translational Speed ◽  
Careful Comparison

We present a physical model that accounts for the motion of rapidly rotating curling rocks. By rapidly rotating we mean that the rotational speed of the contact annulus of the rock about the centre of mass is large compared with the translational speed of the centre of mass. The principal features of the model are: (i ) that the kinetic friction induces melting of the ice, with the consequence that there exists a thin film of liquid water lying between the contact annulus of the rock and the ice; (ii ) that the curling rock drags some of the thin liquid film around the rock as it rotates, with the consequence that the relative velocity between the rock and the thin liquid film is significantly different to the relative velocity between the rock and the underlying solid ice surface. Since it is the former relative velocity which dictates the nature of the motion of the curling rock, our model predicts some interesting differences between the motions of slowly versus rapidly rotating rocks. Of principal note is that our model predicts, and observations confirm, that rapidly rotating curling rocks stop moving translationally well before rotational motion ceases. This is in sharp contrast to the usual case of slow rotation, where both rotational and translational motion cease at the same instant. We have verified this and other predictions of our model by careful comparison with the motion of actual curling rocks.

A Separation Criterion With Experimental Validation for Shear-Driven Films in Separated Flows

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
M. A. Friedrich ◽  
H. Lan ◽  
J. L. Wegener ◽  
J. A. Drallmeier ◽  
B. F. Armaly
Keyword(s):  
Liquid Film ◽  
Gas Phase ◽  
Experimental Validation ◽  
Thin Liquid Film ◽  
Complete Separation ◽  
Separated Flows ◽  
Force Ratio ◽  
Wide Range ◽  
Inertial Surface ◽  
Film Separation

The behavior of a shear-driven thin liquid film at a sharp expanding corner is of interest in many engineering applications. However, details of the interaction between inertial, surface tension, and gravitational forces at the corner that result in partial or complete separation of the film from the surface are not clear. A criterion is proposed to predict the onset of shear-driven film separation from the surface at an expanding corner. The criterion is validated with experimental measurements of the percent of film mass separated as well as comparisons to other observations from the literature. The results show that the proposed force ratio correlates well to the onset of film separation over a wide range of experimental test conditions. The correlation suggests that the gas phase impacts the separation process only through its effect on the liquid film momentum.

Lubricated Friction of Rubber. V. Influence of Rubber Resilience and Hardness on Friction

1968 ◽  
Vol 41 (4) ◽  
pp. 870-880 ◽  
Author(s):  
E. P. Percarpio ◽  
E. M. Bevilacqua
Keyword(s):  
Measurement Error ◽  
Dry Friction ◽  
Road Surface ◽  
Relative Influence ◽  
Test Surface ◽  
Hard Surface ◽  
Wet Friction ◽  
Wide Range

Abstract The dominant importance of hysteresis in lubricated friction of rubber was first outlined by Tabor and has been extensively confirmed since. A number of workers have also shown that dry friction is correlated with hysteresis, but the mechanistic connection is still unclear. Rubber hardness has been less definitely correlated with friction. This may result in part from the choice of surface on which to test the rubber compositions studied. We have previously shown the importance of the test surface and recommended use of wavy glass to simulate actual slippery roads in lieu of a representative road surface. Carr reported our finding that the relative influence of rubber hardness depends on the texture of the hard surface on which it slides. Using the wavy glass and a slippery road surface, we have now studied a very wide range of compositions, both gum and filled, derived from commonly used tire rubbers, as well as others included to extend the range of properties studied. These results fully confirm the importance of hysteresis and more clearly define that of hardness. These two properties together almost completely determine wet friction on slippery roads. Most of the variance not accounted for is attributable to measurement error.

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