Self-sustained oscillation of a submerged jet in a thin rectangular cavity

Self-sustained oscillating jet flow of water in a rectangular cavity, havin g thickness which is small relative to its width, is measured using LDA and PIV, and predicted using a transient two-dimensional computational fluid d ynamic model which incorporates a resistance coefficient for cross-how. The basic geometry represents a scale model of a mould typical of thin slab st eel casting. The frequency of the oscillation was found to be independent o f cavity thickness. It also increased as the cavity width decreased down to some critical value, after which the oscillation ceased. The frequency was observed to increase with nozzle diameter and was found to decrease with i ncreasing length/width ratio of the cavity. The numerical model, with a fix ed dimensionless cross-flow resistance coefficient, was shown to predict th e Strouhal number of the oscillation and the dimensionless mean velocity pr ofiles in the jet extremely well. (C) 2001 Academic Press.