Textile Structure
how cloth is put together
Concept

Poiseuille's law — where it appears

Poiseuille's 1846 result that the volume rate of flow through a tube goes as the fourth power of its radius. The fourth power is why a fabric's coarse pores carry nearly all the flow while its fine pores supply nearly all the pull.

Named by 2 essays across 2 fields — each of them below, with the objects they name alongside it.

The sett moves the flux and not the height. A 20 tex cotton yarn woven at every sett from 8 to 34 threads per centimetre. Above: the hole between the threads lifts from 27 to 234 mm as the cloth closes, while the space between the fibres lifts 6.37 m at every one of them — so the cloth's maximum is the flat line, and the sett does not touch it. Below: the permeability of those holes falls by a factor of 292 over the same range. Both curves are monotone, so there is no optimum — only an interval, ending at the jam at 34.6 threads per centimetre.

The sett decides how much, not how high

Every rung of this ladder so far has found the sett deciding something. This one finds it deciding nothing at all: a cloth's maximum rise is 6.37 m at eight threads per centimetre and 6.37 m at thirty-four, because the sett cannot reach inside a yarn.

setting · Sett Two pore systems in one cloth — 24 threads per centimetre. A plain weave of 20 tex cotton in section, at 24 threads per centimetre, so the yarn is 167 µm across and the clear hole between two picks is 250 µm. That hole's hydraulic radius is 124.8 µm. Inside the yarn, fibres 14 µm across packed at 0.6 leave spaces of hydraulic radius 2.33 µm — 53 times finer, and by Jurin's law 53 times higher: 6.37 m against 119 mm. The yarn's interior is magnified 6 times and the two discs at the foot are the only part drawn at one scale.

How high a cloth wicks

A woven cloth has two capillary systems and they are a factor of twenty to a hundred apart. The one every diagram draws — the hole between four threads — lifts 119 mm. The one nobody draws, inside the yarn, lifts 6.37 m.

applied · Wicking

Named alongside it

The objects these essays reach for when they reach for this one.

Hydraulic radiusInter fibre poreJurin's lawPore radiusWickingContact angleCoverJammingOpening sizePacking factorPermeabilitySett

All concepts