The phrase "allowed to flow" refers to the unrestricted movement of a substance or energy. Synonyms for this phrase include "permitted to move freely," "unhindered flow," "unrestricted current," "unobstructed stream," and "unrestrained flux." These phrases convey the idea that there is no impediment to the natural flow of something. Another synonym is "unencumbered movement," which emphasizes the absence of any obstacle or hindrance to the movement of a substance or energy. Regardless of the specific wording used, these synonyms share a common goal of describing an unimpeded flow of something, without any restrictions or interference.