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...

This paper presents the study of fluid flow and heat transfer in a plain rectangular duct of a solar air heater by using Computational Fluid Dynamics (CFD). The effect of Reynolds number on heat transfer coefficient and friction factor was investigated. A commercial finite volume package ANSYS FLUENT 12.1 is used to analyze and visualize the nature of the flow across the duct of a solar air hea...

coeffcient of  friction  (cof)  for  rubber parts  is one of  the key parameters in their interaction with solid rough surfaces (micrometer to millimeter scales),  such  as  tire-road  interactions. cof  of  rubber  depends  on  viscoelastic properties of rubber, roughness characteristics of the counter-part surface, and process variables such as contact nominal pressure and sliding speed. due ...

The construction of fast and reliable solvers for contact problems with friction is even nowadays a challenging task. It is well known that contact problems with Coulomb friction have the weak form of a quasi-variational inequality [KO88, HHNL88, NJH80]. For small coefficients of friction, a solution can be obtained by means of a fixed point iteration in the boundary stresses [NJH80]. This fixe...

The Hasimoto planar vortex filament is one of the rare exact solutions to the classical local induction approximation (LIA). This solution persists in the absence of friction or other disturbances, and it maintains its form over time. As such, the dynamics of such a filament have not been extended to more complicated physical situations. We consider the planar vortex filament under the quantum ...

Three-dimensional CFD simulations are carried out to investigate heat transfer and fluid flow characteristics of a four-row plain fin-and-tube heat exchanger using the Commercial Computational Fluid Dynamics Code ANSYS CFX 12.0. Heat transfer and pressure drop characteristics of the heat exchanger are investigated for Reynolds numbers ranging from 400 to 2000. Fluid flow and heat transfer are s...