Numerical study of coupled flow in blocking pulsed jet impinging on a rotating wall

In order to study the complex unsteady flow characteristics of pulsed jet impinging on a rotating wall, the Wray–Agarwal turbulence model was adopted. The following conditions were used to simulate the internal flow mechanism, namely: jet with Re = 10,000; rotational speed n = 500 rpm; impinging height H/D = 5; pulse period T = 0.5 s + 0.5 s. The results show that: (1) The flow field structure of pulsed jet impinging the rotating wall is symmetrical about the jet axis. With the development of time, a pair of entrainment vortices and rotating vortices are formed on both sides of the jet and on the rotating wall, respectively. (2) In the vicinity of the jet outlet, the radial distribution of the velocity V gradually becomes non-uniform as time progresses and eventually coincides with the velocity at steady state. (3) During 0 s ≤ t < 0.5 s, the velocity at nozzle-exit increases with time, and the V/V_j along the axis coincides with the steady state. During 0.5 s ≤ t < 1 s, the nozzle-exit velocity V/V_j decreases to 0, along the axis direction, the V/V_j increase first and then decrease. (4) The impact pressure of pulsed jet on the impact wall is greater than that of continuous jet on the impact wall in a certain period when water hammer effect occurs.