decline curve analysis has some advantages over transient well test analysis in which it is not required to shut-in the well and also wellbore storage effects do not exist. few studies have been done on decline curve analysis of naturally fractured reservoirs but there are even some limitations with available models. on the other hand well test could be expensive and in some operational conditi...

Structural health monitoring of cracked structures is one of beloved subject of researchers recently. Consider of crack behavior in the water and energy pipeline is important because of environmental problems. In this paper consider of crack parameters in the underwater pipe subjected to mechanical transient load is investigated. For this purpose, three- dimensional parametric model of cracked ...

In the present study, the author’s previous experimental investigations on the vortex induced vibration of uniform and tapered circular cylinders are numerically simulated. The circular cylinders have medium mass ratios (5.93, 6.1), low mass-damping parameters (0.0275, 0.0279) a mean diameter of 0.028m and an aspect ratio of about 14. A fully coupled two-way fluid-structure interaction (FSI) an...

Due to the nonlinear nature of the Bang-Bang phase-locked loops (BBPLLs), its transient analysis is very difficult. In this paper, new equations are proposed for expression of transient behavior of the second order BBPLLs to phase step input. This approach gives new insights into the transient behavior of BBPLLs. Approximating transient response to reasonable specific waveform the loop tran...

Shaded pole induction motors, despite the simplicity and low cost, are difficult to analyze particularly in the equivalent circuit methods, due to the asymmetric structure, saturation, harmonics, inaccurate estimation of leakage inductances and skew. Hence, 3D numerical methods could be very useful in the design and optimization stage. This paper presents the 3D transient finite element analysi...

this paper undertakes the synthesis of a logic-based switching h2/h∞ state-feedback controller for continuous-time lti singular perturbation systems. our solution achieves a minimum bound on the h2 performance level, while also satisfying the h∞ performance requirements. the proposed hybrid control scheme is based on a fuzzy supervisor managing the combination of two controllers. a convex lmi-b...

this study investigated the performance and aeroelastic characteristics of a wind turbine blade based on strongly coupled approach (two-way fluid structure interaction) to simulate the transient fsi1 responses of hawt2. aerodynamic response was obtained by 3d cfd-urans approach and structural response was obtained by 3d finite element method. aeroelastic responses of the blade were obtained by ...

Given the sophisticated nature of the blast phenomenon in relation to structures, it is of significance to accurately investigate the structure behavior under blast loads. Due to its rapid and transient nature, blast loading is one of the most important dynamic loadings on the structures. Since masonry materials are widely used as the partition and bearing walls in the existing and newly-built ...