Institute of Geonics AS CR, v. v. i.

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.

Duralumin exposed to pulsating
and continuous 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., 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., 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., 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.
Foldyna, J., Sitek, L., Habán, V. Acoustic wave propagation in high-pressure system. Ultrasonics, Vol. 44, Supplement 1, 22 December 2006, pp. e1457-e1460, ISSN 0041-624X.
Foldyna, J., Habán, V., Pochylý, F., Sitek, L. Transmission of acoustic waves. Proceedings of the International Congress on Ultrasonics, Vienna, April 9-13, 2007, Paper ID 1458, Session R12: High power ultrasonic processing. doi:10.3728/ICUltrasonics.2007.Vienna.1458_foldyna.
Pochylý, F., Habán, V., Foldyna, J., Sitek, L. 3D problem of pressure wave propagation in the tube with inconstant cross section. Proceedings of the International Congress on Ultrasonics, Vienna, April 9-13, 2007, Paper ID 1459, Session R21: Physical acoustics. doi:10.3728/ICUltrasonics.2007.Vienna.1459_pochyly.
Foldyna, J., Heiniger, K. Mettler, S., Sitek, L., Ščučka, J. Enhancing of Water Jet Effects by Pulsations. Manufacturing Engineering 4/2007,. pp. 30-33, ISSN 1335-7972.
Bodnárová, L., Sitek L. Hela, R. Foldyna J. Nové možnosti technologie vysokorychlostních vodních paprsků při sanacích betonových konstrukcí. Beton TKS, Roč. 8, č. 6 (2008), s. 44-49. ISSN 1213-3116.
Foldyna, J. Sitek, L. Ščučka, J. Martinec, P. Valíček, J. Páleníková, K. Effects of pulsating water jet impact on aluminium surface. Journal of material processing technology Vol. 209, Iss. 20 (2009), pp. 6174–6180. Elsevier, 2009. ISSN 0924-0136.
Foldyna, J. Research and development of pulsating water jets. In Pacific Rim International Conference on Water Jetting Technology /9./ Proceedings. Koriyama: Water Jet Technology Society of Japan, 2009. S. 171-179. ISBN 4-902590-14-8.
Ščučka, J., Foldyna, J., Sitek, L., Martinec, P., Valíček. J. Testing of fan jet nozzles for pulsating jets generation. 9th Pacific Rim Int. Conf. on Water Jetting Technology, 20. - 23. 11. 2009, Koriyama, Japonsko, IAP, Ltd. 2009, pp. 195-200, ISBN 4-902590-14-8.