Cavitation of a viscous fluid in narrow passages

摘要: The conditions which determine the existence and position of cavitation in narrow passages hydrodynamically lubricated bearings have been assumed to be same as those produce bubbles, namely a lowering pressure below that at gas separates out fluid. This assumption enables certain predictions made some cases are verified, but it does not provide physical description interface between oil air. Theoretical analysis situation seems beyond our present capacity, none experiments so far published has possible measure both most important relevant data, minimum clearance flow through it.A method is described here this done. It turns two physically different kinds can occur. One these well by existing theory assumption. Surface tension plays no part it, text books on hydrodynamic lubrication even mentioned. other kind, akin separation rather than bubble cavitation, depends essentially surface tension. Both appear clearly photographs taken transparent bearings, experimenters do seem distinguished them.The reason why tension, only able supply stresses exceedingly small compared with variation fluid itself, may large effect understood considering viscous tube when blown air applied one end. For any given length rate outflow almost entirely applied, force being negligible; amount left after column reached end