Aleksander  Predovie, 
    Sliding Motion of the Yarn on the Package Surface During Yarn Unwinding,
    Journal of Engineering and Applied Sciences,
    Volume 12,Issue 20,
    2017,
    Pages 5084-5087,
    ISSN 1816-949x,
    jeasci.2017.5084.5087,
    (https://makhillpublications.co/view-article.php?doi=jeasci.2017.5084.5087)
    Abstract: Tension in the yarn and its oscillations during the over-end unwinding of the yarn from stationary
packages depend on the unwinding speed, the shape and the winding type of the package, the air drag
coefficient and also the coefficient of friction between the yarn and the package. The yarn does not leave the
surface package immediately at the unwinding point. Instead, it first slides on the surface and then lifts off to
form the balloon. The problem of simulating the unwinding process can be split into two smaller sub-problems:
the first task was to describe the motion of the yarn in the balloon, the second one to solve the sliding motion.
    Keywords: Dynamics of yarn;friction between yarn and package;balloon theory;boundary comditions;oscillations;simulating