Visualisation and measurement of high-speed pulsating and continuous water jets

• We visualise and analyse structure and flow velocity fields of high-speed water jets.
• The combination of shadowgraph technique and PIV method is tested and verified.
• We compare structure and velocity fields of continuous and pulsating water jets.
• The proposed method contributes to the optimisation of high-pressure systems.
• Knowledge of velocity distribution in jets allows to maximise their disintegration effect.

The results of an experiment focused on the visualisation of pulsating and continuous water jets are presented in this paper. Water jet technology is widely used for surface cleaning, removal of damaged material layers, preparation of surfaces, and in many other applications. The aim of the experiment was to test the applicability of the shadowgraph technique combined with PIV processing algorithms to visualise water jet structure and analyse flow velocity field. Knowledge of the geometry and velocity fields of pulsating water jets generated by a high-pressure system is necessary for the optimal tuning of the system in respect of the maximum disintegration effect on treated material. Visualisation methods also significantly contribute to the development of new pulsating systems at the design stage. The presented procedures and experimental results demonstrate the above mentioned method as an effective analytical tool for the study of water jet geometry and velocity fields. Problems related to the application of this method are also described in the paper, together with a concept of how the problems could be solved.