The Analogy between Hydraulic Jumps in Liquids and Shock Waves in Gases

The theory of the hydraulic jump is presented briefly, and the analogy between this phenomenon and the compression shock wave in gases is pointed out. The results of experimental measurements of hydraulic-jump intersections on a water table are reported. Considerable disagreement between theory and experiment is found. Other investigators have noted a disagreement between theory and experiment for compression-shock intersections in gases. The discrepancy in the aerodynamic case appears unlike that found in the hydraulic case. Possible reasons for the discrepancy in the hydraulic case are discussed; some sources of error are peculiar to hydraulic jumps and do not apply to compression shocks. Such factors limit the utility of the water table as an analog device.