Simultaneous measurements of water impact on a two-dimensional body

This study utilizes a high-speed charge coupled device (CCD) camera as the data acquisition system to simultaneously measure the pressure and flow field. The measurement system can be triggered by an external optical sensor, to obtain the free surface and pressure variations in each time step of the initial stage of water impact. The whole field image was observed by a high-speed area scan sensor camera. Almost no interval between photographing moving objects was allowed owing to the extremely short transfer time and high exposure sensitivity of the camera. Following image transfer, this characteristic and the hardware computational function of a video card not only allowed for binarization, accumulative addition but we could also quickly identify the track of a moving object and obtain the image and numerical data which we needed. Moreover, the flow characteristics are observed via a flow following ''seeding'' particles, and the digital particle tracking velocimeter (DPTV) so that the flow field velocity distribution can be measured.