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Intensification of high-speed water jet effects

Research activities are directed to study of dynamic behavior of pulsating water flow, definition of natural relations of processes of excitation and propagation of high-frequency pressure pulsations in liquid and their utilization for generation of pulsating high-speed liquid jets.

Complex dynamic processes occurring during excitation and propagation of high-frequency pressure pulsations in liquid are studied both theoretically with aid of numerical simulations and CFD methods and experimentally using direct measurement of frequency and amplitude of dynamic pressure in high-pressure system and stagnation force generated by the impact of pulsating jet.

Process of pulse forming in high-speed water jet downstream from the nozzle exit is studied with aid of special method of pulsating jet visualization (based on stroboscopic effect) and subsequent image analysis. Interaction of pulsating jet and material is studied using optical methods and image analysis to define processes occurring during the interaction as well as effects of the pulsating jet on the material surface. Cutting and disintegration effects of pulsating water jets are tested on various materials to compare their performance with continuous ones.

The objective of the research is to understand fundamental processes of generation and transmission of pressure pulsations in high-pressure system, forming of pulsating jet and its interaction with material.

Selected publications

  • Foldyna, J., Sitek, L., Švehla, B., Švehla, Š. Utilization of ultrasound to enhance high-speed water jet effects. Ultrasonics Sonochemistry, Vol 11/3-4, 2004, Elsevier B. V., pp 131-137.
  • Sitek, L., Foldyna, J. Možnosti využití modulovaného vodního paprsku při sanaci betonu. Beton TKS, 2/2002, str. 38 - 41, ISSN 1213-3116. (in Czech)
  • Sitek, L., Foldyna, J. Modulovaný vodní paprsek – nástroj pro opracování kovů? Konstrukce, 3. ročník, číslo1/2004, str. 66 – 67, ISSN 1213-8762. (in Czech)
  • Foldyna, J., Sitek, L. Modulated vs. Continuous Jets: Performance Comparison. Proceedings of the 2001 WJTA American Waterjet Conference, Hashish (ed.), WJTA, 2001, pp. 523 – 535.
  • Sitek, L., Foldyna, J., Ščučka, J., Młynarczuk, M., Sobczyk, J. Quality of bottom surface of kerfs produced by modulated jets. Proceedings of the 16th International Conference on Water Jetting, Lake (ed.), BHR Group 2002, pp. 359 - 368. ISBN 1 85598 042 8.
  • Sitek, L., Foldyna, J., Ščučka, J., Švehla, B., Bodnárová, L., Hela, R. Concrete and rock cutting using modulated waterjets. Proceedings of the 7th Pacific Rim International Conference on Water Jetting Technology, Jeju 2003, Chung-In Lee, Seokwon Jeon, Jae-Joon Song (eds.), Korean Society of Water Jet Technology, 2003, pp. 235 – 244, ISBN 89-95026-6-2 93550.
  • Foldyna, J., Sitek, L., Jekl, P., Švehla, B. Measurement of dynamic pressure and force effects of modulated water jet. Proceedings of the 7th Pacific Rim International Conference on Water Jetting Technology, Jeju 2003, Chung-In Lee, Seokwon Jeon, Jae-Joon Song (eds.), Korean Society of Water Jet Technology, 2003, pp. 125-132, ISBN 89-95026-6-2 93550.
  • Foldyna, J., Martinec, P., Sitek, L. Water jets in dimension stone cutting and surface treatment. Dimension Stone 2004. New Perspectives for a Traditional Building Material (Proceedings of the International Conference on Dimension Stone 2004, 14-17 June 2004, Prague, Czech Republic). Přikryl (ed.), A. A. Balkema Publishers, Taylor & Francis Group, London, 2004, pp. 303-308, ISBN 90 5809 675 0.
  • Foldyna, J., Sitek. L. CFD model modulovaného vodního paprsku. Sborník 10. uživatelské konference FLUENT 2004. Střasák (ed.), Techsoft Engineering s. r. o., Praha, 2004, pp. 2-33 – 2-39, ISBN 80-239-3138-5. (in Czech)
  • Foldyna, J., Sitek, L., Martinec, P., Ščučka, J., Jekl, P. & Młynarczuk, M. Rock cutting by pulsing water jets. Eurock 2005 – Impact of Human Activity on the Geological Environment. Konečný (ed.), A. A. Balkema Publishers, Taylor & Francis Group, London, 2005, pp. 129 – 134, ISBN 04 1538 042 1.
  • Foldyna, J., Říha, Z., Sitek, L. Proudění v trysce s pohyblivou stěnou. Sborník 11. uživatelské konference FLUENT 2005. Střasák (ed.), TechSoft Engineering s. r. o., Praha, 2005, pp. 183 - 188, ISBN 80-239-5127-0. (in Czech)
  • Foldyna, J., Sitek, L., Ščučka, J., Martinec, P. & Jekl, P. Pulsating water jets: A tool for dimension stone cutting. Proceedings of the 4th International Conference Mining Techniques 2005, Feliks, Filipowicz (eds.), AGH Krakow, 2005, pp. 37 – 46, ISBN 83-915742-7-X.
  • Foldyna, J., Sitek, L., Jekl, P., Martinec, P. & Ščučka, J. Pulsating water jets. Documenta Geonica 2005, Institute of Geonics ASCR Ostrava, 2005, pp. 18-29.