20.500.12556/RUL-142025 Water hammer simulation using simplified convolution-based unsteady friction model Omission of frequency-dependent hydraulic resistance (skin friction) during modelling of the water hammer phenomenon is unacceptable. This resistance plays a major role when the transient liquid flow occurs in rigid-walled pipes (steel, copper, etc.). In the literature, there are at least two different modelling approaches to skin friction. The first group consists of models based on instantaneous changes in local and convective velocity derivatives, and the second group are models based on the convolution integral and full history of the flow. To date, more popular models are those from the first group, but their use requires empirical coefficients. The second group is still undervalued, even if based on good theoretical foundations and does not require any empirical coefficients. This is undoubtedly related to the calculation complexity of the convolution integral. In this work, a new improved effective solution of this integral is further validated, which is characterised with the use of a simplified weighting function consisting of just two exponential terms. This approach speeds the numerical calculations of the basic flow parameters (pressure and velocity) significantly. Presented comparisons of calculations using the new procedure with experimental pressure runs show the usefulness of the proposed solution and prove that it maintains sufficient accuracy. water hammer hydraulic transients unsteady friction convolution-based model numerical simulation vodni udar neustaljeno stensko trenje hidravlični prehodni pojavi konvolucijski model računske simulacije true false true Angleški jezik Slovenski jezik Članek v reviji 2022-10-17 09:15:04 2022-10-17 09:15:10 2022-10-18 03:47:13 0000-00-00 00:00:00 2022 0 0 20 str., art. 3151 iss. 19 Vol. 14 2022 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 2022-10-01 532:004.94 2073-4441 10.3390/w14193151 125809923 Urbanowicz_..._-Water_hammer_simulation_using_simplified_convolution-based_unsteady_friction_model.pdf Urbanowicz_..._-Water_hammer_simulation_using_simplified_convolution-based_unsteady_friction_model.pdf 1 44299470581D5A8F284A0E23AFDFEA1D ad776f0f6ec2f8fb27d5d9b60019c789346794ef8eca8b295d3706e04501e062 bb0a1ca3-4deb-11ed-9c94-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=163273 https://www.mdpi.com/2073-4441/14/19/3151 1 62ff1cd1-4deb-11ed-9c94-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=163272 Fakulteta za strojništvo 0 0 0