The recent work of Gharib, Rambod, and Shariff @J. Fluid Mech. 360, 121 ~1998!# studied vortex rings formed by starting jets generated using a piston-cylinder mechanism. Their results showed that vortex rings generated from starting jets stop forming and pinch off from the generating jet for sufficiently large values of the piston stroke to diameter ratio (L/D), suggesting a maximization princi...

Cardiac MR group Lund, Dept. of Clinical Physiology, Lund University, Lund, Sweden Full list of author information is available at the end of the article Figure 1 Design and construction of the vortex ring flow phantom. a) 2D view of the flow rectifier and vortex ring tank. All measures are in millimeters (mm). b) 3D view of the flow rectifier and vortex ring tank. c) Pump design. A servo motor...

Friction loss in an internal combustion engine largely depends on elastohydrodynamic lubrication. The piston compression ring is a contributor to such parasitic losses the subsystem. complex elastodynamics of are responsible for transient and regime-altering film that affects lubrication liner contact conjunction. current paper will discuss radial, lateral deformation, axial twist, its effect p...

In the paper a comprehensive model of a piston ring pack motion on an oil film has been presented. The local oil film thickness can be compared to height of the combined roughness of sliding surfaces of piston rings and cylinder liner. Equations describing the mixed lubrication problem based on the empirical mathematical model formulated in works of Patir, Cheng and Greenwood, Tripp have been c...

The sealing performance will directly affect the operation of downhole robot under HTHP condition. Traditional analysis methods are that temperature and pressure is loaded respectively. This can not really evaluate performance. Besides, simulation process is: Step 1: pre-compress O-ring to produce contact force. According pressure, select compression ratio calculate displacement slip ring. 2: l...