The PJET, a testing method inspired by test rigs at Cambridge’s Cavendish Laboratory, simulates water droplet impacts by propelling high-pressure water through a 0.8 mm nozzle to form a focused water jet. This jet is segmented by a rotating disc with 10 mm holes at 20 Hz, generating segments with a 40 Hz impact frequency to mimic conditions experienced by aircraft surfaces during heavy rain at 225 m/s and a rainfall rate of 25 mm/h.

The setup includes pulsating stabilization and a nozzle-sample distance of 60 mm. The water jet speed is adjustable via water pressure and up to 225 m/s. The sample, mounted on a programmable YZ stage, can be moved in a grid pattern and angled variably to the jet, enhancing test precision. Water film formation is prevented by using a nozzle that expels 3-bar pressurized air to disperse the water on the sample effectively.