Surging in Laboratory Pipeline with Steady Inflow

Surges of head and discharge were studied experimentally in a laboratory pipeline which had check structures spaced at equal distances along the pipe. Surges developed when the downstream portion of the check structures did not flow full. The surges were initiated by the release of air entrained in the downstream leg of the check structures, and the surges were amplified as the flow passed through the successive pipe reaches. The experiments were made for various inflows which were steady at the upstream end of the pipe. Plots of surge magnitude vs. inflow rate show two peaks. One peak apparently corresponds to surges initiated by air release through the vent downstream of the check structures; the other peak, to surges initiated by air release through the downstream part of the check structure. The nonlinear momentum equation was integrated numerically to predict the growth of the discharge surge from one pipe reach to the next. The general character of the results is presented. The results were in good agreement with the experiments.