lazenby asks:
This isn’t strictly a dynamics question, but I was wondering how hot a stream of fluid has to be before it can no longer lower the average temperature of a body placed in its flow. As an example, how hot a day does it have to be before fans stop cooling you down? What’s the relation and the math to reach for here?
Wonder no further! You seek the subject of heat transfer–specifically forced convection. Here’s a brief look at how to calculate the cooling due to a fan. Click to enlarge each page.
