how to find drag force on droplet
 

I'm simulating a droplet sitting on a plate under shearing air flow. What I did was:
1. built a chamber in design model and then meshed it
2. in setup adapted the region occupied by droplet and patch water phase to that region, applied shearing air flow and then calculate

I want to find the drag force but in the automatic export tab we can not simply export the drag force. Can anyone help me on this?