for main jet at m 0 87 d h 0 166 and d lt 0 300 with different microjet speeds where fig3 a is baseline jet fig3 b is with no microjet injection fig3 c is with microjet injection at m 0 87 fig3 d is at m 1 and fig3 e is at m 1 42 the no microjet injection case suggests that central insertion tube 114 plays a vital role in reducing the edge tone amplitude to study the effect of the tube length different central insertion tube lengths d l t are considered in fig4 a 4b 4c and 4d specifically 0 500 0 375 and 0 300 are considered for simulations with main jet at m 0 87 and d h 0 1666 comparison of the spl is shown in fig4 a 4b 4c and 4d which proves that the central insertion tube 114 reduces the amplitude of the edge tone specifically fig4 a 4b 4c and 4d show the comparison of spl for main jet at m 0 87 d h 0 1666 and different lengths of central insertion tube without microjet injection d l t where fig4 a is baseline jet where l t 0 mm fig4 b is where d l 1 0 500 fig4 c is where d l t 0 375 and fig4 d is where d l t 0 300 the suppression mechanism in the passive edge tone suppression method can be explained as follows and as illustrated in fig5 a and 5b when the central insertion tube 114 u2018 without microjet injection u2019 is introduced inside the.