Velocity field of an axisymmetric pulsed, subsonic air jet

Experimental Investigation of Particle Removal from Surfaces by Pulsed Air Jets

“…This motion is characterized by a certain preservation of the initial pulsed structure of the unsteady jet up to fairly large distances from the nozzle, such that the oscillatory motion is clearly observed even at distances as large as x=d 0 > 20, especially if d 0 is small, of the order of 5-6 mm. The experiments of Bremhorst and Hollis (1990) corroborate this nding, showing that complete merging of the pulses is reached at x=d 0 > 50. They also found that the streamwise component of the turbulence intensity shows a marked difference between pulsed and steady jets and concluded that the ow is dominated by the periodic component for distances up to x =d 0 D 50: Binder and Favre-Marinet (1981) note that in the case of imposed pulsations the regime where the pulsations decay is reached around x=d 0 D 15 for a much larger Strouhal number, St D 0.23.…”

“…Pulsed Jets-Results from the Literature In this section we consider the experimental data and theoretical results on pulsed jets from the literature (Bremhorst 1979;Binder and Favre-Marinet 1981;Bremhorst and Hollis 1990;Vulis and Yarin 1978). Some relevant parameters reported in the literature are summarized in Table 2.…”

“…Zumbrunnen (1997, 2000) used a driven ball valve. Sailor et al (1999) used Bremhorst and Hollis (1990) 25.4 36.6 10 0.007 Zumbrunnen and Aziz (1993) 50 £ 5 ** 0-142 0-0.326 Zumbrunnen (1997, 2000) 50 £ 5 Not reported explicitly 0-82 0-0.13 Sailor et al (1999) 14 80 20-60 0.009-0.042 ¤ This is the disk rotation frequency. The pulse frequency (and Strouhal number) is twice the given value.…”

“…It is common to characterize pulsed jets by their Strouhal numbers, Figure 1. Devices used to obtain pulsed jets: (a) Vulis and Yarin (1978); (b) Bremhorst (1979) and Bremhorst and Hollis (1990); and (c) Zumbrunnen and Aziz (1993).…”

“…Binder and Favre-Marinet (1981) generated the pulses by a butter y valve. Bremhorst (1979) and Bremhorst and Hollis (1990) used a valve formed by 2 synchronized rollers. Zumbrunnen and Aziz (1993) constructed a wheel-blade assembly.…”