I honestly would have never thought that but then again what you are saying makes sense. You have also got me looking into some case airflow videos on YouTube. Again thanks for the info.
While YouTube can sometimes be helpful, it's often very misleading. Especially with things like how to improve case airflow.
Airflow is the result of higher pressure area of air moving into lower pressure area of air.
Fan impellers draw air on intake side side (creating lower pressure area) and push air out exhaust side (creating higher pressure area).
I'm sure you've seen fans advertised as "high pressure" fans or "airflow" fans. High pressure rated fans are 1.3-1.9mm H2O at 1500-1800rpm.
To put that into prospective, standing at sea level we have 1.836 mm H2O more pressure on our ankles/feet than on our chest/shoulders 5 feet above sea level. That is why things like our case grille mesh, case filters, even cables create significant resistance to and reduce airflow. Part of that resistance is the result of turbulence.
Airflow around something round:
Airflow around something square:
Not a great example but hopefully it helps. If you've seen snow drifts along fences, by bushes, etc, you've seen how disrupting smooth flow of air slowing it down causing snow moving in faster air to fall to the ground and builds drifts.
Hope that all makes sense.
