Measuring wave impact induced pressures with a pressure mapping system

• The use of a Pressure Mapping System (PMS) for capturing the distribution of wave impact induced pressures is proposed.
• A purposely designed calibration rig is described.
• PMS results are compared with pressure transducer and load cell measurements for a variety of breaking conditions and a satisfactory agreement is reported.
• Overall, the use of PMS to acquire insights on the spatial structure of wave impact induced pressures is encouraged.

The use of a pressure mapping system for measuring wave impact induced pressures is evaluated in this paper. A set-up and a calibration methodology are suggested and employed for this work. The system is validated against pressure transducer and load cell measurements and for a range of waves breaking on a vertical seawall. For a large number (120 measurements for each case considered) of breaking and broken waves interacting with the wall, the peak pressure (Ppeak) profiles and the pressure distribution maps reported by the system agree well with results acquired using pressure transducers. Although the pressure mapping system tends to underestimate Ppeak, differences on the mean of the 3, 5 and 10 highest Ppeak range within ± 10%, while for the majority of the measurements the error on the integral of the acting pressures (the acting force compared with the force measured by the load cell) ranges within ± 20%. It is concluded, that through careful calibration and set-up the pressure mapping system has the capacity to provide pressure distribution maps with a good accuracy. It is not, however, considered to constitute the absolute alternative to pressure transducers and thus a combined use is suggested for applications where a very high level of accuracy is required.