Fluid Mechanics

Approximately 1000 kg/m³ (or 1.94 slug/ft³).

γ = ρg. For water, γ ≈ 9810 N/m³ (or 62.4 lb/ft³).

The ratio of the fluid's density to the density of water (SG = ρ_fluid / ρ_water); it is dimensionless.

Dynamic viscosity μ relates shear stress to velocity gradient; kinematic viscosity ν = μ/ρ.

τ = μ (du/dy), where du/dy is the velocity gradient (rate of shear strain).

Shear stress is linearly proportional to the rate of shear strain (constant viscosity), e.g., water and air.