Jet impact angle on chute downstream of aerator

Chute aerators protect spillways from cavitation damage. Several parameters affect their efficiency, which were intensively discussed in literature. One implicit parameter is the cavity jet impact angle at the re-attachment point of the flow on the chute bottom, which may however not be defined a priori by the designer. The herein conducted experimental research derived this angle and a related general prediction of it, and shows its effect on the aerator performance. The experiments indicate that no distinctive effect occurs if considering the air entrainment coefficient, but that the relative air detrainment rate downstream of the re-attachment point significantly augments with increasing impact angle.