flowját
Flowját is a theoretical construct used in fluid dynamics and systems analysis to describe the directional alignment between a velocity field and a specified gradient field, capturing how readily advective transport follows a scalar-gradient direction. In this framing, the local flowját at a point is defined as the cosine of the angle between the velocity vector v(x) and the gradient ∇φ(x) of a scalar field φ(x).
Mathematically, flowját(x) = (v · ∇φ) / (|v| |∇φ|) when both v and ∇φ are nonzero; its value lies in the interval
Flowját is used conceptually to assess how effectively a flow carries a scalar along a gradient, and
Practical considerations include handling zero-gradient or zero-velocity zones, where flowját is undefined, and choosing an appropriate
Related concepts include gradient, flux, advection, diffusion, and vorticity.