Modeling of netting motion in water

Abstract

A kinetic model was made in order to analyze underwater netting-movement by numerical computation. A fixed range centering on a knot of the netting was used as a fundamental calculation element. A mass in an element was concentrated on a knot. As the forces acting upon a element, besides gravity, fluid resistance, and the added mass force, the moment of force and twine tension were adopted. The empirical formula was used for water resistance. The kinetic equation was formed from the balance of forces at every knot point, and the locus of a knot was pursued by numerical computation.
Water resistance and tension dominated in forces acting on a knot in a stationary state. And the value of gravity and moment of force are smaller than those, but, this time, the moment of force couldn't be ignored compared with gravity.
In order to increase calculation accuracy, it needs to make netting form at the time of simulation in an actual condition, because, the netting form would be variable according to the spring-constant of the bar. Thus, not only a drag coefficient but a spring-constant which relates to the netting form would be an important factor.