Stribeck Curve Visualizer

Feel the boundary → mixed → hydrodynamic transition by dragging the sliders

Compute the Hersey number Hn = η · U / P from viscosity, speed, and contact pressure, and watch the friction coefficient μ slide through the three lubrication regimes in real time. Tweaking composite roughness σ or the boundary value μ_bl reshapes the curve and moves the minimum.

Boundary lubricationμ = 0.119

Hn = 5.00×10⁻¹⁰ · f_a = 0.995 · λ ≲ 1

Solid-on-solid asperity contact dominates. Wear is likely; boundary-additive films are the line of defence.

Set conditions

Presets

Operating conditions (point)

Dynamic viscosity η0.100Pa·s

Speed U0.500m/s

Contact pressure P100MPa

Surface & contact (curve shape)

Composite roughness σ0.10µm

Boundary friction μ_bl0.120

Raising σ shifts the transition (and the minimum) to the right; lowering it shifts left. μ_bl sets the height of the boundary plateau.

The λ correspondence is an approximate hint. For the rigorous λ, use the Lambda Ratio Calculator.

In the contact view, asperities (micro-roughness) of the upper and lower surfaces touch directly in boundary (red highlights) and are fully separated by the oil film (blue) in hydrodynamic.

Assumptions & Limitations

This visualiser uses an educational semi-empirical model. Real friction coefficients depend strongly on contact geometry, materials, lubricant, temperature, and additive behaviour, and must ultimately be measured on a tribometer.
The curve uses μ(Hn) = μ_bl · f_a(Hn) + c_v · Hn, where f_a is the asperity load-share fraction. The constants c_v, p, k_σ are tuned to produce visually clear regime transitions, not to reproduce a specific tribological test.
Regime boundaries (f_a = 0.8 / 0.2) and the λ correspondence (λ ≈ 1 / 3) are approximate. Rigorous λ requires the EHL film-thickness calculation — see the Lambda Ratio Calculator.
Hn = η · U / P uses η in Pa·s, U in m/s, and P in Pa. Real machines typically fall in the 10⁻¹² to 10⁻⁵ Hn range covered by the chart.

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Oil Blend Calculator

Compute the kinematic viscosity of a two-oil blend (Refutas)

Stribeck Curve Visualizer

Feel the boundary → mixed → hydrodynamic transition by dragging the sliders

Assumptions & Limitations

This visualiser uses an educational semi-empirical model. Real friction coefficients depend strongly on contact geometry, materials, lubricant, temperature, and additive behaviour, and must ultimately be measured on a tribometer.

The curve uses μ(Hn) = μ_bl · f_a(Hn) + c_v · Hn, where f_a is the asperity load-share fraction. The constants c_v, p, k_σ are tuned to produce visually clear regime transitions, not to reproduce a specific tribological test.

Regime boundaries (f_a = 0.8 / 0.2) and the λ correspondence (λ ≈ 1 / 3) are approximate. Rigorous λ requires the EHL film-thickness calculation — see the Lambda Ratio Calculator.

Hn = η · U / P uses η in Pa·s, U in m/s, and P in Pa. Real machines typically fall in the 10⁻¹² to 10⁻⁵ Hn range covered by the chart.