Is it obligatory to repeat the prayer if non-viscous, yellow discharge is found after performing ablution and prayer, without cleansing the body of it?

If you suffer from continuous discharge ( سلس الإفرازات), perform Wudu' for each prayer after its time has begun, and pray as much as you wish until the time for that prayer exits. What comes out will not harm you.

However, if you do not suffer from continuous discharge, then wait for the discharge to stop before praying. The normal vaginal wetness is pure ( طاهرة ) and does not necessitate Istinja' (cleansing). As for yellowish discharge, it is impure ( نجسة ) and necessitates Istinja'.

If you find yellowish discharge after the prayer and it is likely that it exited after the prayer, you do not need to repeat the prayer. But if you are certain that it exited during the prayer or before it, and you do not suffer from continuous discharge, then you must repeat the prayer.