An earth boring bit includes a bit body including plurality of PDC cutter elements and a fluid plenum connecting a fluid inlet to at least one fluid orifice. Furthermore, a ledge formed between a bottom of the fluid plenum and the at least one fluid orifice includes a relief region formed therein located across a flow change angle. Additionally, a method to improve a polycrystalline diamond compact drill bit body design includes determining flow change angles from a fluid plenum into a fluid orifice and modeling a relief region on a ledge to optimize fluid into the fluid orifice.