Erm, there is no 2d in reality. So, the experiment is 0.74m deep. You've just found some of your error. Scale the force to the experiment depth or the experimental result to the Fluent result.

Sir, I divided the experimental force by experimental width (I hope that's the right procedure) and got almost comparable results.nNow regarding the run-up (height upto which the water elevates over the breakwater face). Won't it remain the same whatever the width is right? So is there any need to scale the run-up corresponding to the width of tank?n