Modélisation des textures de surface profondes basée sur la résolution des équations de Navier–Stokes par éléments finis et l’analyse de leurs effets sur les écoulements avec cavitationen lubrification hydrodynamique

Abstract

This study presents a numerical analysis of the hydrodynamic performance of textured surfaces in lubrication. The simulations rely on a finite element model directly solving the Navier– Stokes equations, making it possible to overcome the limitations of classical approaches based on the Reynolds equation. First, the influence of texture geometry is studied in the absence of cavitation in order to isolate purely geometric effects. Rectangular and semi-elliptical textures are compared. The results show that semi-elliptical textures generate higher lift and a more stable flow than rectangular textures, although they produce greater drag. The study also examines the influence of manufacturing defects producing inclined sidewalls in rectangular cavities, showing that deep cavities can benefit from them, whereas shallow textures experience a reduction in load-carrying capacity and an increase in friction. Second, a cavitation model based on a barotropic equation of state is introduced in order to represent pressure and density variations in cavitation regions. The model is validated by comparison with experimental and numerical results from the literature and demonstrates a good ability to predict pressure distributions and cavitation zones in hydrodynamic bearings. Finally, the combined influence of texture geometry and cavitation is studied in textured surfaces. The results show that increasing the texture depth leads to a reduction in lift and drag forces, while higher sliding velocities increase them. Circular textures systematically generate higher lift and drag forces than rectangular profiles. Regarding frictional behavior, the friction coefficient increases with texture depth and sliding velocity. Circular textures systematically exhibit lower friction coefficients than rectangular textures. Overall, these works highlight the importance of inertia effects, texture geometry, and cavitation in hydrodynamic lubrication regimes and provide guidance for the design of textured surfaces that simultaneously optimize friction reduction and load-carrying capacity.

Date	11 May 2026
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Raynald Guilbault (Supervisor) & Noël Brunetière (Co-supervisor)