I am working on a two phase simulation for pulsatile blood flow in a straight vessel with an injection into it from a catheter that is a constant flow rate.

I need to include a turbulence model but it appears to be a very big can of worms as to which turbulence model to pick as well as what parameters to implement on the chosen turbulence model.

Does anyone have any advise for model selection as well as parameter selection?

My pulsatile flow ranges from 20cm/sec to ~115cm/sec through a 6.35mm diameter "vessel" and the constant injection of 206cm/sec through a 1.17mm catheter. the geometry is essentially two concentric tubes axially aligned.