20.500.12556/RUL-177382 Comparison of 1D Euler equation based and 3D Navier-Stokes simulation methods for water hammer phenomena 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.  water hammer cavitation water column separation CFD Euler equation Navier-Stokes equations OpenFOAM method of characteristics vodni udar kavitacija pretrganje vodnega stolpca Eulerjeva enačba Navier-Stokesove enačbe metoda karakteristik true false true Angleški jezik Slovenski jezik Članek v reviji 2025-12-22 12:04:28 2025-12-22 12:04:34 2025-12-30 04:02:11 0000-00-00 00:00:00 2025 0 0 12 str. no. 9/10 Vol. 71 2025 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 519.6:004.94 2536-3948 10.5545/sv-jme.2025.1340 260397827 RAZ_Vovk_Nejc_2025.pdf RAZ_Vovk_Nejc_2025.pdf 1 441E1F844A55470017AB9FEDD6D5B9CC e98095e6dda026cef60631802d4e942e2a43fcf38070e15ec4b6f4f866ed5b8e aea43711-df25-11f0-9328-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=224398 https://dk.um.si/IzpisGradiva.php?id=96192 1 8d69b262-df25-11f0-9328-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=224396 https://www.sv-jme.eu/sl/article/comparison-of-1d-euler-and-3d-navier-stokes-simulation-methods-for-water-hammer-phenomena/ 1 8f3ecedf-df25-11f0-9328-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=224397 Fakulteta za strojništvo Strojniški vestnik 0 0 0