turbulent viscosity ratio on a large duct

newbie

I searched the forum but I couldn't quite get the answer to my problem.

I ran a simulation where water flows through a very large square duct (5x5x30m).

solver: k epsilon standard Inlet: velocity inlet 1 m/s duct wall: smooth wall outlet: outflow

Mesh: quad mesh with 0.3 size (resulting in about 50,000 nodes). gravity on. specified operating density=0

The problem gets the turbulent viscosity limit error (1e5). Strange thing is that when I plotted viscosity ratio, almost all of the water body not close to wall had viscosity ratio around 1e5. How could this be so high in such a simple flow? Is this normal?