Derivation of a lumped parameter system model of a flow passage simultaneously modeling resistance and inertia and verification in basic flow passages

A laminar flow resistance in a pipe is usually used as a representative model of flow resistance because it is convenient to use and often gives reasonable resistance value in a small size pipe under steady state condition. However, the laminar flow resistance model in a pipe is not applicable in an oil flow passage of a real circuit because a flow passage has complex shape in a real circuit. Furthermore, the mathematical model of fluid column in a pipe made in inviscid flow condition is often used as an inertial model in considering dynamic condition. In the real condition of operating oil-hydraulic circuit, the above mentioned two effects, a complex shape of flow passage and flow dynamic characteristics, appears in viscous flow condition. A new model or modeling method to include and solve these effects reasonably becomes necessary. A new modeling method using CFD is introduced in this paper.