IwTmNAL ADVISORY cOMaTTEE FOR AERONAUTICS

The transient response of the pressure-remting relief v~ve in, a hydraulic circuit is analyzed by means of an electrical analogy of the hydraulic circuit. Measurements of the transient response of a hydraulic relief valve are presented and are compared with responses calcuhted from the dif-ferential equation of the equivalent electric network. The comparison of experimental and analytical responses shows that the response of the relief valve can be adeqmtel.y predicted by means of the equivalent network. The analysis of a typical relief valve by means of the eqpival.ent network indicates that viscous damping is negligible and that the prin-cipal.damping is derived from the flow resistance of the various ele-ments of the hydraulic circuit. An expression is analytically developed that yields directly the area-ltit relation for the relief valve for stable valve operation over wide “flow-rateranges