先进材料疑固实验室 Viscosity of liquid metal Laboratory of Advanced Materials Solidification The ratio u/y is called the rate of shear deformation or shear velocity,and is the derivative of the fluid speed in the direction perpendicular to the plates.Isaac Newton expressed the viscous forces by the differential equation Bu T=μ0y where t=F/A,and ou/oy is the local shear velocity.This formula assumes that the flow is moving along parallel lines and the y-axis,perpendicular to the flow,points in the direction of maximum shear velocity.This equation can be used where the velocity does not vary linearly with y,such as in fluid flowing through a pipe. shear stress,r gradient, velocity,u 上浒充通大学 SHANGHAI JIAO TONG UNIVERSITYViscosity of liquid metal The ratio u/y is called the rate of shear deformation or shear velocity, and is the derivative of the fluid speed in the direction perpendicular to the plates. Isaac Newton expressed the viscous forces by the differential equation where τ = F/A, and ∂u/∂y is the local shear velocity. This formula assumes that the flow is moving along parallel lines and the y-axis, perpendicular to the flow, points in the direction of maximum shear velocity. This equation can be used where the velocity does not vary linearly with y, such as in fluid flowing through a pipe