Flow structure, wall pressure and heat transfer characteristics of impinging annular jet with/without steady swirling

The detailed impinging annular jet characteristics with/without induced swirling motion are experimentally studied. Obtained flow and wall pressure data confirm the classical observation for conventional annular impinging jet, with the flow exhibiting simple round impinging jet-like features at sufficiently large separation distances. In contrast, no such transition occurs in the presence of swirling. At short and intermediate separation distances, the swirling annular jet causes more non-uniform distributions of wall pressure and heat transfer on the impingement plate compared to the conventional annular jet. However, the reverse holds at large separation distances.