where:

**v**is the maximum^{}velocity of the object relative to the fluid (SI units: m/s)*L*is a characteristic linear dimension, (travelled length of the fluid; hydraulic diameter when dealing with river systems) (m)*μ*is the dynamic viscosity of the fluid (Pa·s or N·s/m^{2}or kg/(m·s))*ν*(nu) is the kinematic viscosity (*ν*=*μ*/*ρ*) (m^{2}/s)*ρ*is the density of the fluid (kg/m^{3})

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