Visualization of Flow in Soft Elastohydrodynamic Lubrication
Year: 2026
Type: other
Abstract: Direct experimental measurement of in-plane velocity fields in soft elastohydrodynamic lubrication (EHL) contacts remains challenging due to confined geometry and small film thickness. In this study, we visualize and quantify internal flow beneath a rigid glass sphere sliding on a compliant polydimethylsiloxane (PDMS) substrate using high-viscosity silicone oil seeded with 1-5 µm fluorescent tracer particles. Particle trajectories obtained from bottom-view imaging were processed into time-averaged velocity fields and streamlines, allowing direct comparison with numerical solutions of the Reynolds-elasticity, elastohydrodynamic lubrication (EHL) problem formulated in cylindrical coordinates. Friction measurements suggest that, at the concentrations used, tracer particles did not alter the fluid flow and lubrication regime, and film-thickness calculations confirmed that the particle size was compatible with the accessible gap under the tested loads and sliding velocities. The measurements reveal flow separation at the leading edge, reconvergence at the trailing edge, and depth-dependent transport pathways within the lubrication film. Comparison with cavitating and non-cavitating simulations further suggests that tensile-pressure regions strongly influence streamline topology and transport within the contact. These findings provide direct experimental evidence of internal flow organization in soft EHL and establish new links between pressure distribution and flow structure in compliant lubricated contacts.
Source: AIP Publishing
Authors: Anand Jagota, Haibin Wu, Yue Wu, C. Hui
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7214042870