Investigations of the flow behavior are currently carried out experimentally on models of hydraulic turbines. Quantities
such as unsteady velocity can be acquired using PIV or LDV techniques, static wall pressure using steady or unsteady
pressure transducers and wall shear stress using hot-film anemometry. More rarely acquired however, the unsteady total
pressure at different locations in the flowstream would give more information on the flow dynamics and would be a key
component for setting boundary conditions for CFD simulations. Following the example of classical Pitot tubes, which
can only give averaged pressure values though, we have developed a five-hole pressure probe with embedded sensors
that can measure unsteady values of total pressure, local flow velocity and direction. The probe head is designed to have
a minimum impact on the flowstream, and the miniature sensors are placed in a cross configuration compared to the
probe's support axis.
This paper focuses on the utilization of normalized calibration coefficients and their use for unsteady values, and on the
justification for using our cross sensor repartition. The calibration setup is presented briefly, including a water potential
jet that requires the calculation of specific calibration coefficients.
Different phenomena were observed during experimentation. Their impact on the accuracy of the probe is analyzed. The
probe's operation range for this particular calibration setup is discussed. Finally, we focus on the influence of the sensors
repartition on the tridimensional shape of the calibration coefficients, and we provide a way to calculate the first
approximate solution for the reverse calculus while the sensors are not aligned with the probe's arm.