An experimental investigation is performed to study the effects of jet-exit conditions on the pulsating jets. The flow visualization by a pulsed hydrogen bubble technique is used to observe the vortex formation from rectangular cross section chokes. The chokes have four different lengths. The pulsating jets are forced by the pulsation with large amplitude and low frequency. The Strouhal number is 0.23. In the unpulsating jets, vortices are formed in shear layers due to the Kelvin-Helmholtz instability. The jets from the short chokes produce symmetric patterns of small vortices. The vortex evolution from the long chokes is asymmetry. In the pulsating jets, the symmetrical vortex pair due to the strong acceleration of discharge velocity rolls up from the corner of choke.

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