In human thermodynamics, flow can refer to a number of movement or energy characterizations, such as "psychological" flow, Gibbs energy flow, thermodynamic flow, or even the flow of human molecules in bulk, such as on a busy expressway, as studied in the field of human chemistry. [1]

Mental flow

See main: Csíkszentmihályi flow

In psychodynamics, Csíkszentmihályi flow or simply “flow” is a state of focused, engaged, and optimal mental activity, quantified by energy and entropy measures, in which a sense of timelessness and outputs of great productivity emerge. [2]

References
1. (a) Thims, Libb. (2007). Human Chemistry (Volume One), (preview), (Google books). Morrisville, NC: LuLu.
(b) Thims, Libb. (2007). Human Chemistry (Volume Two), (preview), (Google books). Morrisville, NC: LuLu.
2. (a) Csíkszentmihályi, Mihály. (1990). Flow - the Psychology of Optimal Experience. Harper Perennial.
(b) Thims, Libb. (2007). Human Chemistry (Volume One), (preview). (pg. 173). Morrisville, NC: LuLu.