Moved to Dynamic Viscosity Simulator

The viscosity-flow page has been consolidated into the dynamic viscosity simulator.

Dynamic Viscosity Simulator

Simulator Library

How to Use

  1. Select fluid type (water at 20°C: 1.002 mPa·s, SAE 10W oil at 40°C: 100 mPa·s, or enter custom viscosity)
  2. Input flow conditions: pipe diameter (mm), volumetric flow rate (L/min), and temperature range (°C)
  3. Calculate Reynolds number and flow regime; simulator outputs shear stress (Pa) and pressure drop per meter (kPa/m)

Worked Example

ISO VG 32 hydraulic oil (32 cSt at 40°C = 32 mPa·s) flowing through a 16 mm ID steel pipe at 60 L/min and 50°C: Reynolds number = 1847 (laminar). Shear stress at wall = 18.4 Pa. Pressure drop = 12.6 kPa/m. At 80°C, viscosity drops to 16 mPa·s; Reynolds number increases to 3694 (transitional), pressure drop reduces to 6.3 kPa/m.

Practical Notes

  1. Mineral oils exhibit steep viscosity-temperature slopes (typically -3% per °C); synthetic PAO oils show -2.5% per °C for better thermal stability in hydraulic systems
  2. Laminar flow (Re < 2300) dominates in precision metering: micro-orifices, proportional valves, and low-flow gear pump circuits
  3. Account for non-Newtonian behavior in high-shear polymer additives; kinetic viscosity differs from dynamic viscosity by fluid density (ν = η/ρ)