Subterranean fans on 24/7 Y or N?

Im no professional but I agree with @HeavyHittah i think your to far in your grow your stems looks grown. But still the big fan you have might still cause problems with leaf bending or breaking. I personally use a small wall fan from amazon you can find one for under . You can use 2 on either end of the room if you need to to help the air flow. My plant is small but the stem is strong.

I doubt having the fan on the stems at this stage would make much difference . Just one fan on ground level will be fine not pointed at the plants just to increase airflow. Best way for airflow is to train and spread your plants out and defoliate where needed. I have never used a fan on the floor never had issues. My inline extractor fan is quite powerful though, that helps .

I use one or two of these oscillating smaller ones with speed controller plugged into intelligent USB port on extension lead 24/7. Even with 8 plants in a 4 x 4 there has been little or no wind burn effect even on closest plants. Airflow is important

Wind damage to lower leaves isn't something I'd worry about, to be frank... getting good air flow to the plant (which will help avoid bud rot) is worth losing some lower leaves.... my opinion! Good luck!