Theoretical aspects concerning working fluids in hydraulic systems

Some Theoretical Results concerning Diphasic Fluids in Thin Films

We are interested in a model for diphasic fluids in thin flows taking into account both the hydrodynamical and the chemical effects at the interface between the two fluids. A limit problem in “thin films” is introduced heuristically. It is a system coupling the Reynolds equation and the hydrodynamical Cahn-Hilliard equation. We study the mathematical properties of this system, and prove an exis...

Complex Fluids and Hydraulic Fracturing.

Nearly 70 years old, hydraulic fracturing is a core technique for stimulating hydrocarbon production in a majority of oil and gas reservoirs. Complex fluids are implemented in nearly every step of the fracturing process, most significantly to generate and sustain fractures and transport and distribute proppant particles during and following fluid injection. An extremely wide range of complex fl...

Flammability Properties of Hydraulic Fluids

Hydraulic jumps at boundaries in rotating fluids

We consider three-dimensional hydraulic jumps (shocks) propagating along boundaries in rotating fluids. This study is motivated by earlier work (Fedorov & Melville 1995), which dealt with the evolution to breaking of nonlinear Kelvin waves. We obtain the jump relations and derive an evolution equation for the jump as it propagates along the boundary. It is shown that after some initial adjustme...

Mobile Working Hydraulic System Dynamics

This thesis deals with innovative working hydraulic systems for mobile machines. Flow control systems are studied as an alternative to load sensing. The fundamental difference is that the pump is controlled based on the operator’s command signals rather than feedback signals from the loads. This control approach enables higher energy efficiency and there is no load pressure feedback causing sta...