This study utilizes silver nano-fluid filled flat heat pipe. It is aimed at effect of various concentrations on flat heat pipe thermal performance by air-cooling testing equipment. The particles used in these experiments were silver particles 35 nm in size. The base working fluid was pure-water. Nano-fluids were prepared using a two-step method. In the experiment, the thickness and length of th...

VI-1 Abstract – In conducting analysis of systems that have failed as a result of lightning and transients, we have observed repeated incidences associated with corrugated flexible tubing. The nature and frequency of lightning strokes is considered. The failure process is investigated. Standards and articles provide adequate minimum design for installation. Ten areas of electrical systems corre...

Direct numerical simulation of transitional pipe flow is carried out in a long computational domain in order to characterize the dynamics within the saddle region of phase space that separates laminar flow from turbulent intermittency. For Reynolds numbers ranging from Re=1800 to 2800, a shoot and bisection method is used to compute critical trajectories. The chaotic saddle or edge state approa...

Three-dimensional finite element modeling of residual stresses in a girth-welded pipe is presented in this paper, with an emphasis on modeling procedures for the global residual stress characteristics. The shell element model with a heat source moving along the circumferential joint is demonstrated to be cost effective and capable of predicting the global residual stress features. Transient res...

Buried steel fuel pipelines are critical lifelines for the society and the economy but are very vulnerable to earthquake-induced ground failure. Traversing seismic areas inevitably results in several pipe-fault crossings. Fault rupture forces a buried pipeline to undergo deformations that could be substantial and heavily endanger its integrity. Due to the grave consequences of a potential pipe ...

Transitional pipe flow is modeled as a one-dimensional excitable and bistable medium. Models are presented in two variables, turbulence intensity and mean shear, that evolve according to established properties of transitional turbulence. A continuous model captures the essence of the puff-slug transition as a change from excitability to bistability. A discrete model, which additionally incorpor...

Lower-branch traveling waves and equilibria computed in pipe flow and other shear flows appear intermediate between turbulent and laminar motions. We take a step towards connecting these lower-branch solutions to transition by deriving a numerical method for finding certain special disturbances of the laminar flow in a short pipe. These special disturbances cause the disturbed velocity field to...

The diffraction model of a cavity, suggested by Lawson, Bane and Sands is generalized to a step-out transition, Using this model, the high-frequency impedance is calculated explicitly for the case that the transition step is small compared with the beam-pipe radius. In the diffraction model for a small step-out transition, the total energy is conserved, but, unlike the cavity case, the diffract...

Plane Couette flow and pressure-driven pipe flow are two examples of flows where turbulence sets in while the laminar profile is still linearly stable. Experiments and numerical studies have shown that the transition has features compatible with the formation of a strange saddle rather than an attractor. In particular, the transition depends sensitively on initial conditions and the turbulent s...

In this work, XFEM is employed to obtain the stress intensity factors (SIFs) of a semi elliptical part through thickness axial crack. In XFEM, additional functions are employed to enrich the displacement approximation using partition of unity approach. Level set functions are approximated using higher order shape functions in the crack front elements to ensure the accurate modeling of the crack...