Fluir vs. correr

The Spanish verbs 'fluir' and 'correr' both have meanings related to flow or movement. While both can be used in relation to liquids, they are not exact synonyms and there are subtle differences between their uses.

Fluir

'Fluir' is a verb often used to describe the motion of liquids, typically water, similar to the English word 'flow'. It suggests a smooth, consistent movement.
El agua fluye por el río.
(The water flows down the river.)
La sangre está fluyendo de la herida.
(Blood is flowing from the wound.)
El vino fluye libremente en la fiesta.
(The wine is flowing freely at the party.)

Correr

'Correr' primary meaning is 'to run', but it can also be used to mean 'flow', particularly when describing flowing liquids as well. Compared to 'fluir', it might suggest a faster or more forceful movement.
El río corre rápido después de la lluvia.
(The river runs fast after the rain.)
La tinta corre por el papel.
(The ink runs across the paper.)
Corre el agua de la fuente.
(The water flows from the fountain.)

Summary

Both 'fluir' and 'correr' can describe liquids in motion, however, while fluir tends to imply a smooth and steady flow, correr might suggest more energy or speed. It's also important to consider that 'correr' has other meanings beyond this context.