Original scientific paper In this work a new approach considering numerical modelling of waterhammer dissipation and attenuation is proposed. The classical Allievi liquid flow model has been extended with the Brunone unsteady friction model which includes separation of the local and convective unsteady friction factor. A widely-adopted approach in solving this model is treatment of the unsteady...

Large-eddy simulations (LES) of turbulent flow in a smoothwall pipe at Reynolds numbers based on the pipe Radius R and wall friction velocity in the range Reτ = 2,000−2,000,000 are discussed. Using a Reynolds number based on D and the bulkflow velocity, then corresponding values are ReD = 91,800 − 165,000,000. For the LES, the spectral-element code SEMTEX was used combined with the stretched-vo...

This paper discusses a methodology of semi-active structural control using a variable friction damper. The presented algorithm is quite simple and straightforward, in which only the slip level of the friction damper is controlled in response to the interstory response velocity of the damperinstalled story so as to maintain the target constant ductility factor. In conducting control there is adv...

In this paper, the slipping friction is considered in the problem of a progressive wave of real fluids propagating over a permeable bottom.In the interface of soil and fluid, the “no-slip” condition is relaxed and a sliding friction coefficient is introduced. Thus, the slipping effect and the permeability of the bottom on the velocity near the seabed can be studied. The results indicate that th...

This paper presents the results of an experimental study on capillary tubes commonly used as expansion device in household refrigerators and freezers. The experiments were performed with HFC-134a at different condensing pressures and level of subcooling. The pressure and temperature profiles along the capillary tubes were measured in each test run. The data set was then used to evaluate the sui...

-In this work are shown the results obtained from subjecting copper coated with diamond by triboadhesion to a wearing process with a plane rider. Here it is shown the ratio of the normal to shearing forces, called friction factor, as an indication of the resistance of the surface. Micro-Vickers tests shown a 23.2 % increase of hardness of the coated probes compare to non coated probes. Although...