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Bagnold's fluid refers to a suspension of neutrally buoyant particles in a Newtonian fluid such as water or air. The term is named after Ralph Alger Bagnold, who placed such a suspension in an annular coaxial cylindrical rheometer in order to investigate the effects of grain interaction in the suspension. ==Constitutive relations== By experiments described in his 1954 paper, Bagnold showed that when a shear flow is applied to the suspension, then the shear and normal stresses in the suspension may vary linearly or quadratically with the shear rate, depending on the strength of viscous effects compared to the particles' inertia. If the shear and normal stresses in the mixture (suspension: mixture of solid and fluid) vary quadratically with the shear rate, the flow is said to satisfy ''Bagnold’s grain-inertia flow''. If this relation is linear, then the motion is said to satisfy ''Bagnold’s macro-viscous flow''. These relationships, particularly the quadratic relationship, are referred to as the Bagnold rheology. Although Bagnold used wax spheres suspended in a glycerin-water-alcohol mixture, many subsequent shear-cell experiments for both wet and dry mixtures, as well as computer simulations, have confirmed these relations. Bagnold's rheology can be used to describe debris and granular flows down inclined slopes. 〔 〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Bagnold's fluid」の詳細全文を読む スポンサード リンク
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