20.500.12556/DKUM-96188 Editorial on the special issue entitled “Towards a sustainable and recyclable future with wood and wood-based composites” Water hammer phenomena in pipelines can induce significant transient pressure surges, leading to structural failures and operational inefficiencies. This study presents a comparative analyzis of two numerical approaches for simulating water hammer: a one-dimensional (1D) inviscid model with added friction based on the Euler equations and the method of characteristics, and a three-dimensional (3D) viscous model utilizing the Navier-Stokes equations in OpenFOAM. Benchmarking problems are solved first, then both methods are used to study a 3.4 km long DN400 pipeline subject to sudden pump failure by analyzing pressure surges, cavitation, and water column separation. The 1D model effectively predicts transient pressure waves and cavitation conditions with minimal computational cost, while the 3D model provides a detailed representation of multiphase flow dynamics, including cavitation bubble growth and collapse via the volume of fluid method. To mitigate adverse effects, a dynamic combination air valve is introduced, and its effectiveness in reducing pressure surges and cavitation is demonstrated. The results highlight the trade-offs between computational efficiency and accuracy in modelling water hammer events and underscore the importance of protective measures in pipeline systems. Pojav vodnega udara v cevovodih lahko povzroči porast tlaka, kar vodi do strukturnih okvar cevovodov. Ta študija predstavlja primerjalno analizo dveh numeričnih pristopov za simulacijo vodnega udara: enodimenzionalni (1D) neviskozni model z dodanim trenjem, ki temelji na Eulerjevih enačbah in metodi karakteristik, ter tridimenzionalni (3D) viskozni model, ki uporablja Navier-Stokesove enačbe v OpenFOAM simulacijskem okolju. Najprej je prikazana validacija pristopov, nato obe metodi uporabimo za simulacijo 3,4 km dolgega cevovoda DN400, ki je izpostavljen nenadni okvari črpalke, kjer analiziramo tlačni udar s pretrganjem vodnega stoplca. 1D model učinkovito napoveduje prehodne tlačne valove in kavitacijske pogoje z minimalnimi računskimi stroški, medtem ko 3D model zagotavlja podrobno študijo dinamike večfaznega toka, vključno z rastjo in kolapsom kavitacijskih mehurjev po metodi končnih volumnov. Za ublažitev neželenih efektov je predlagan kombinirani zračni ventil, za katerega smo dokazali učinkovitost pri zmanjševanju tlačnega udara in kavitacije. Rezultati poudarjajo kompromise med računsko učinkovitostjo in natančnostjo pri modeliranju pojavov vodnega udara in poudarjajo pomen zaščitnih ukrepov v cevovodnih sistemih.  wood-based material renewable resources recycling new materials materiali na osnovi lesa obnovljivi viri recikliranje novi materiali true false true MDPI Angleški jezik Slovenski jezik https://www.mdpi.com/1996-1944/18/21/4848 Članek v reviji 2025-12-09 09:30:21 2025-12-09 09:30:21 2025-12-10 03:12:05 0000-00-00 00:00:00 2025 0 0 2 str. iss. 21, [article no.] 4848 Vol. 18 Oct. 2025 0000-00-00 Zaloznikova Objavljeno NiDoloceno 2025-10-02 2025-10-21 2025-10-23 677.46 259347203 10.3390/ma18214848 1996-1944 materials-18-04848.pdf materials-18-04848.pdf 1 9B742564FBCB6F960AE5404E4C274AAA 42c7bc3e4e77fdac8b5908573cab6e4e51969b2d8f23de1f5095c952a3b15d18 db99b4c9-d4dd-11f0-b0df-00155d000105 https://dk.um.si/Dokument.php?lang=slv&id=201248 https://www.mdpi.com/1996-1944/18/21/4848 0 e919ea9c-d4dd-11f0-b0df-00155d000105 https://dk.um.si/Dokument.php?lang=slv&id=201249 Fakulteta za strojništvo 0 0 0