converging problem
 

im new with ansys and how it works so im a bit lost here. i have created a mesh for a delta wing in icem. i created the surface mesh for the delta wing then created a volume mesh that expand outwards from the surface mesh for the farfield.
Then i export it to fluent. i've set the inlet of the farfield to velocity-inlet and outlet to outlet-vent. i used a k-epsilon standard model to run this test and set it for 10000 iterations. But dont know why the simulation converges in just 1 min for 150 iterations. my mesh seems to be dense enough for simulation to run but its not converging correctly. why is this so?
sorry if its not informative enough, you can ask me for more information, i just need help desperately. thank you