Fluid Flow & Phase Transitions

Primes about how substances flow, mix, and change phase across boundaries: transport and exchange (diffusion, convection, counter-current exchange, permeability, porosity), and threshold-driven phase behavior (nucleation, phase separation, percolation, metastability) at interfaces between regimes.

17 primes in this family — primes that sit near one another in abstraction space (k-means over structural-signature embeddings). Each is shown with its short description.

• Asymmetric Flux — A direction- or channel-selective boundary drives accumulation even under symmetric forcing.
• Convection — Circulatory process via gradients.
• Counter-Current Exchange — Two streams flowing in opposite directions along a shared interface preserve a near-constant driving gradient along the whole contact, lifting extraction efficiency toward unity.
• Diffusion — Spread over time.
• Ecotone — A transitional zone of measurable depth where two regimes overlap and mix, generating gradients, elevated exchange, and zone-specific structure that neither regime alone hosts.
• Interfacial Energy — A per-unit-boundary cost that scales with seam length rather than bulk, driving systems toward configurations with less total boundary unless opposed.
• Metastability — A system persists in a locally stable configuration that is not the global optimum, held there by a barrier that routine disturbances cannot clear.
• Mixed Layer — An actively-stirred, locally-homogeneous surface zone that buffers a stratified interior, joined to it by a sharp discontinuity.
• Mixing — Redistribute distinguishable constituents among local regions so composition becomes less dependent on original position, while preserving the total amount being rearranged.
• Nucleation — A metastable system cannot transition globally because a new phase's surface cost exceeds its volume benefit at small size; transition begins only when a seed crosses the critical-nucleus threshold and then grows.
• Percolation — Local, often random short-range connections accumulated across a population suddenly produce system-spanning connectivity once their density crosses a critical threshold.
• Percolation Threshold — On a network substrate, a system-spanning connected cluster appears suddenly at a sharp critical density of links, transforming isolated pieces into one reachable whole.
• Permeability — A bounded medium selectively passes some carrier through connected pathways.
• Phase Diagram — Maps system states.
• Phase Separation — A previously mixed system spontaneously demixes into distinct, spatially segregated regions once like-with-like interactions outweigh mixing above a threshold.
• Porosity — A bulk holds a distributed fraction of internal void space whose total, connectivity, and distribution jointly set storage capacity, transmissibility, and mechanical strength.
• Threshold-Driven Order Emergence — Order after critical point.