The phrase "circulation system" refers to a network of structures that transports something, such as blood or air, throughout a body or a system. Full definition
They must also model the air circulation systems correctly as regulators of energy transmission at both the sea / air interface and the air / space interface. (newclimatemodel.com)
The process is a key component global ocean circulation system. (geomar.de)
What has not been fully understood is how the blood circulation system in the brain «knows» that it needs to ramp up blood flow to respond to the increased demand. (sciencedaily.com)