Document Type : Original Article


Department of Power Mechanical Engineering, Faculty of Engineering Minoufiya University, Shebin El-Kom, Egypt


This study reports experimental and numerical results exposing the effect of the impingement
surface geometry on the flow field for impinging low and high speed jets. Air jets from convergent
circular nozzle of 10 mm exit diameter have been allowed to impinge normally on a flat plate,
hemispherical, and conical surfaces. Experiments were done with varying the stagnation pressure
from 1.2 to 2 bar. The Reynolds number based on the nozzle exit diameter for this range of
stagnation pressure was changed from 7.5 x 105
to 3 x 106
. The distance between the nozzle exit
plane and the test surface was varied from 10 to 80 cm. Measurements of static and total pressure
were made by the help of pressure taps made on the test surfaces and a pitot tube. The numerical
simulations were performed by the solution of Navier-Stokes equations with a k- ε model.
Behaviors of the impinging jets were compared with those of a free jet. The flow field was found
to be depend on the stagnation pressure, spacing between the nozzle and impinging surface, as
well as the impinging surface geometry. A comparison of the predicted behavior of the jet with
those obtained from experimental results gives a good agreement