Cognitive radio (CR) is a promising technique that offers a solution to the spectrum scarcity problem by dynamically exploiting the underutilization of the spectrum among the bands. There are numerous procedures to detect spectrum using CRs like energy detection (ED), matched filter detection (MFD), cyclostationary feature detection (CFD), waveform based detection (WBD) and so on. In this paper...

In this paper, a CFD-based method coupling with overset grid technique is used to directly simulate the 20/20 zigzag maneuver of the fully appended ONR Tumblehome ship model. Numerical computations are carried out by our in-house CFD code naoe-FOAM-SJTU, which is developed on the open source platform OpenFOAM. The overset grid module is used to predict the ship motions with 20/20 zigzag maneuve...

System identification is evaluated as an efficient and accurate technique for modeling unsteady aerodynamic forces for use in time-domain aeroelastic analysis. In the system identification methodology, the constant coefficients of a linear system model are fit to the computed response time histories from a 3-D, unsteady CFD solver. The resulting model of the unsteady CFD solution is independent...

PURPOSE The aim of this study was to validate a computational fluid dynamics (CFD) simulation of flow-diverter treatment through Doppler ultrasonography measurements in patient-specific models of intracranial bifurcation and side-wall aneurysms. METHODS Computational and physical models of patient-specific bifurcation and sidewall aneurysms were constructed from computed tomography angiograph...

The purpose of this paper is to survey the di erent issues regarding runtime load balancing for CFD related application. Di erent execution framework for parallel CFD application is possible. They di er by load balancing algorithm usage. Iterative static graph partition is one solution of this problem. Other solution is to do dynamic load balancing by data migration during runtime as initial ma...

Computational Fluid Dynamics (CFD) is used to predict natural ventilation flows in an enclosure with upper and lower openings connected to the environment. The natural driving forces are wind combined with buoyancy. CFD simulations were carried out by varying the strengths of buoyancy under a constant assisting wind effect. Simulation results of the volume flow rates through the enclosure, the ...

This report describes work undertaken during a 2005 / 2006 summer internship project funded by the Queensland Parallel Supercomputing Foundation (QPSF). The work pertains to the development of a set of tools implementing texture based visualization techniques for the visualisation of Computational Fluid Dynamics data (CFD). While work was undertaken to address each of the project goals, the mos...

The CFD analysis and optimization of multi-element airfoils are presented. Window-Embedment technique is used to automatically generate the grids along with the geometry evolving. The CFD code named NSAWET is employed for performance and flow field analysis. The Genetic Algorithms are used in along with gradient methods to get a good compromise of global optimization capability and efficiency. ...

In this paper we emphasize a technique based on graph theory that allows for deriving both a dimensionally reduced object model required for setting up a thermal multizone model and a geometrical model for defining a single or multiple CFD domains in a building model together with incidence matrices correlating these models. The incidence matrices are an essential precondition for establishing ...

In computational fluid dynamics (CFD), the use of high-performance computers is often indispensable, simply to manage the high request for computation time and storage. We consider a particular two-dimensional aircraft design problem and report on the use of automatic differentiation (AD) to obtain accurate derivatives rather than approximations based on numerical differentiation. More precisel...