How Close Is Too Close? Applying Fluid Dynamics Research Methods to PC Cooling

In April 2025, LinusTechTips visited NASA's Langley Research Center at the invitation of the Flow Physics and Control Branch to seek an answer to the question: how far does a case fan have to be from a flat surface?

The article - authored by Dr.Louis Edelman - delves deeper into the test design and components, expanding on the approaches and methods used.

I’m kind of surprised there isn’t a CFD setup for PC builders yet. We could model all the parts and run some simulations, as the last hurrah for our old systems. Manufactures could show off their cred by making increasingly detailed models of their parts. It would all be very fun.

Another tip: Blowing air onto a component, instead of sucking it away, is much more effective for cooling. Basically if you put your hand where the cooled component is you should be able to feel the airflow.

In practice this meant flipping the "exhaust" fans in one of my systems. It resulted in temperatures that were consistently a few degrees lower. Note in this instance there wasn't any ducting involved.

Was this one of the trips on the good-as-new plane? The video was an interesting watch.