RESEARCH ARTICLE Total pressure fluctuations and two-phase flow turbulence in hydraulic jumps Hang Wang • Fre ´de ´ric Murzyn • Hubert Chanson Received: 31 July 2014 / Revised: 30 September 2014 / Accepted: 19 October 2014 / Published online: 5 November 2014 Ó Springer-Verlag Berlin Heidelberg 2014 Abstract The large-scale turbulence and high air content in a hydraulic jump restrict the application of many tradi- tional flow measurement techniques. This paper presents a physical modelling of hydraulic jump, where the total pressure and air–water flow properties were measured simultaneously with intrusive probes, namely a miniature pressure transducer and a dual-tip phase-detection probe, in the jump roller. The total pressure data were compared to theoretical values calculated based upon void fraction, water depth and flow velocity measured by the phase- detection probe. The successful comparison showed valid pressure measurement results in the turbulent shear region with constant flow direction. The roller region was char- acterised by hydrostatic pressure distributions, taking into account the void fraction distributions. The total pressure fluctuations were related to both velocity fluctuations in the air–water flow and free-surface dynamics above the roller, though the time scales of these motions differed substantially. List of symbols C Time-averaged void fraction C max Local maximum time-averaged void fraction in the shear flow region D # Dimensionless diffusivity in the turbulent shear region D* Dimensionless diffusivity in the free-surface region d 1 Inflow water depth immediately upstream of the jump toe (m) F Bubble count rate (Hz) F clu Longitudinal bubble cluster count rate (Hz) (F clu ) max Maximum cluster count rate in the shear flow region (Hz) F fs Characteristic free-surface fluctuation frequency (Hz) F max Maximum bubble count rate in the shear flow region (Hz) F p (H) Upper total pressure fluctuation frequency (Hz) F p (L) Lower total pressure fluctuation frequency (Hz) Fr 1 Inflow Froude number, Fr 1 ¼ V 1 = ffiffiffiffiffiffiffiffiffiffiffiffiffi g  d 1 p g Gravity acceleration (m/s 2 ) h Upstream gate opening (m) L r Length of jump roller (m) P Time-averaged total pressure (Pa) P k Kinetic pressure (Pa) P max Maximum mean total pressure in the shear flow region (Pa) P o Piezometric pressure (Pa) p 0 Standard deviation of total pressure (Pa) p 0 max Maximum total pressure fluctuation (Pa) Q Flow rate (m 3 /s) Re Reynolds number, Re ¼ q  V 1  d 1 =l T Time lag for maximum cross-correlation coefficient (s) T 0.5 Time lag for auto-correlation coefficient being 0.5 (s) Tu Turbulence intensity Tu 00 Decomposed turbulence intensity of high- frequency signal component H. Wang (&)  H. Chanson School of Civil Engineering, The University of Queensland, Brisbane, QLD 4072, Australia e-mail: hang.wang@uqconnect.edu.au F. Murzyn ESTACA Campus Ouest, Parc Universitaire de Laval Change ´, BP 53061, Laval Cedex 9, France 123 Exp Fluids (2014) 55:1847 DOI 10.1007/s00348-014-1847-9