Filament tension
= Filament tension
{title2=$T$}
Filament tension is the axial force enforcing local <inextensibility>. Its force density is $\partial_s(T\mathbf r_s)$. A pre-existing constant tension contributes $Ty_{xx}$ to small-slope transverse dynamics; in an unloaded, initially straight filament, tension induced by transverse motion begins at second order in amplitude.