Thickness of liquid film formed by impinging jets on a concave wall

The theoretical analysis of the liquid flow flowing over the flat solid wall derived in a previous paper is extended to the film flow on the concave wall. In addition, the equations used to predict the liquid film thickness on the concave wall are derived. The measurements of the film thickness on the concave wall are performed by the contact needle method, while varying the impingement angle, the curvature of the concave wall, the distance between the measurement point and the impingement point, and the jet Reynolds number. The predictions of the film thickness distribution are compared with the measurements. The comparisons show that the predictions of the film thickness agree well with the measurements, except in the region near the symmetry axis of the liquid film. In the region near the symmetry axis, the predictions overestimate the film thickness. The discrepancies appear to be a result of the assumptions in the theoretical analysis with respect to the film flow near the impingement point.