Weft Insertion by Water Jet

Abstract

In order to make clear a mechanism of weft yarn insertion in a water-jet loom, the flow velocity of the jet, the static pressure on the weft surface, and the driving force acting on the weft in the vicinity of the nozzle exit have been analyzed by utilizing the matched asymptotic expansion technique on the basis of results of the authors' previous paper. The present results are as follows. The flow of jet near the weft surface is perturbed by using the small parameter (the reciprocal of the square root of the Reynolds number). The flow velocity of the jet near the weft surface gradually decelerates, and hence the driving force acting on the weft gradually decreases. The static pressure on the weft surface of the jet portion rapidly decreases to atmospheric pressure.