Smoke wire flow visualization was used to investigate the characteristics of the flow structures of a round jet inclined impingement on the concave surface in limited space.Reynolds number of impingement

inclined jet angle

the ratio of the jet distance to the diameter of the jet hole and the relative curvature(the ratio of the diameter of jet hole to the diameter of concave surface) were changed to study the rules of flow structures varying with these parameters.At the same time

the developing and disappearing phenomena of the induced vortex were analyzed.All the experimental results show that

around the stagnation region

it can form swirl structure and generate vortex because of inclined jet and curvature of target concave.The central angle of the impingement fluid separated from the target surface became larger with the increase of jet Reynolds.And the separating angle also increased with the increasing ratio of the jet distance to the diameter of the jet hole

while the range of induced vortex became smaller.It was also found in experiments that

because of the influence of the inclined impingement’s angle

it is easier to generate vortex at the left of the stagnation region where the relative jet angle is smaller.