SciPost Submission Page
The friction of tilted skates on ice
by J. M. J. van Leeuwen
This is not the current version.
|As Contributors:||J.M.J. van Leeuwen|
|Submitted by:||van Leeuwen, J.M.J.|
|Submitted to:||SciPost Physics Core|
|Subject area:||Fluid Dynamics|
The friction felt by a speed skater is calculated as function of the velocity and tilt angle of the skate. This calculation is an extension of the more common theory of friction of upright skates. Not only in rounding a curve the skate has to be tilted, but also in straightforward skating small tilt angles occur, which turn out to be of noticeable influence on the friction. As for the upright skate the friction remains fairly insensitive of the velocities occurring in speed skating.
Submission & Refereeing History
Reports on this Submission
Anonymous Report 2 on 2020-1-15 Invited Report
Nice problem, which would be very original if the same authors had not already publish in SciPost in 2017 a very similar problem.
The article has been written very rapidly without taking care of too many details. Furthermore it relies upon many equations of ref.6
This article studies the friction on the ice skates as a function of the inclination angle of the skater in curved track. The main results is that because of the hydrodynamic pressure of the melted ice the angle of the skate is not the exactly the same than that of the skater body. The problem is nice but the article relies upon many results of ref.6 of the same author which makes the reading quite annoying. The author could have at least quoted the number of the equation of ref.6, which he is referring too. Indeed the article gives the impression of having been written very fast giving just a list of equations with very short comments. For example is never said explicitly that l<<R, the limit of \xi are not well defined, figure 3 is too schematic and very difficult to understand. The lis could be continued. Finally I do not understand how the length l disappear from the final results. This length should be related to the other parameter but I do not understand how.
As a conclusion the article is an application of the theory developed in ref 6 published in SciPost in 2017. Thus the novelty is very weak but as I said the problem is nice. Taking into account that the previous article has been published on the same journal I am not against in considering the present article for publication in SciPost. In any case it cannot be published in the present form and a substantial rewriting is necessary. The author has also to explain if there are new physics effects with respect to ref.6.
Anonymous Report 1 on 2020-1-10 Invited Report
This paper (I will refer to it as JVL) presents a dynamical model of ice friction which predicts ice friction as a function of skate blade tilt angle and skater velocity.
In its essential physics, this paper is virtually identical to the model presented in an earlier paper, published six years ago in one of the top journals in the field. Specifically, I refer to:
Lozowski, E.P., Szilder, K. and Maw, S, 2013: A model of ice friction for a speed skate blade. Sports Engineering. DOI 10.1007/s12283-013-0141-z.
I will call this earlier paper LSM. Both JVL and LSM predict ice friction for a tilted and an upright skate. The essential physics in JVL and LSM are similar. Both JVL and LSM predict that friction increases substantially with skate inclination angle. The main difference seems to be that LSM agrees very well with published measurements (see LSM Figs 12, 13, 14 and 15), while JVL states that his predicted friction “values are still about half those found in real skating experiments”.
In view of this comparison, I would suggest that the present author should first of all acknowledge the existence of LSM (at present it is not included in the bibliography) and point out the similarities between the two models. He should also identify in what ways he considers his model to be an improvement on LSM. And he needs to explain why, if it is a theoretical improvement, his model’s agreement with experiments is not as good as that found in LSM. If the present author makes these changes, I am prepared to recommend publication. Otherwise, I must recommend that the paper be rejected on the basis that it is almost identical to an existing paper, but it does not improve on the existing paper when the theoretical results are compared with experimental results.