background: various variance reduction techniques such as forced detection (fd) have been implemented in monte carlo (mc) simulation of nuclear medicine in an effort to decrease the simulation time while keeping accuracy. however most of these techniques still result in very long mc simulation times for being implemented into routine use. materials and methods: convolution-based forced detectio...

Recent significant improvements to the development of CFD-based unsteady aerodynamic reduced-order models (ROMs) are implemented into the FUN3D unstructured flow solver. These improvements include the simultaneous excitation of the structural modes of the CFD-based unsteady aerodynamic system via a single CFD solution, minimization of the error between the full CFD and the ROM unsteady aerodyna...

This paper illustrates a step-by-step process on how to use "The Manual for Verification, Validation, and Reporting of Indoor Environment CFD analyses" developed by ASHRAE. The details of the manual are further explained through an example of indoor environment modeling (an office with mechanical displacement ventilation). The verification, validation, and reporting do not have to be documented...

The integration of optimization algorithms with computational fluid dynamics (CFD) is becoming more practical as the software becomes more robust and the hardware more efficient. In order to investigate the application of CFD-based optimization methods in the chemical process industry, two polymer die design examples were explored using different slot die geometries, different CFD codes, and di...

Accurate CFD simulation of coupled outdoor wind flow and indoor air flow is essential for the design and evaluation of natural cross-ventilation strategies for buildings. It is widely recognized that CFD simulations can be very sensitive to the large number of computational parameters that have to be set by the user. Therefore, detailed and generic sensitivity analyses of the impact of these pa...

Computational Fluid Dynamics (CFD) simulations provide a variety of data mining challenges and present an opportunity for novel solutions. A core challenge is that CFD computations can require weeks of computation on expensive high performance clusters, delaying investigation of results until a fully converged solution is obtained. 21st Century Systems, Inc. and Brigham Young University have be...

This work examines the parallel scalability characteristics of commercial CFD software FLUENT and STAR-CD for up to 256 processing cores, and research CFD software CDP from Stanford University for up to 512 cores – for transient CFD simulations that heavy in IO relative to numerical operations. In three independent studies conducted with engineering contributions from the University of Cambridg...

Current multizone airflow network models assume air momentum effects, contaminant concentrations and air temperatures are uniformly and homogeneously distributed in a zone of a building. These assumptions can cause errors for zones where air and/or contaminant are not well mixed. A coupled multizone-CFD program has been developed to improve the multizone model by applying a CFD model to those p...

Computational fluid dynamics (CFD) probably plays a greater part in the aerodynamic design of turbomachinery than it does in any other engineering application. For many years the design of a modern turbine or compressor has been unthinkable without the help of CFD and this dependence has increased as more of the flow becomes amenable to numerical prediction. The benefits of CFD range from short...

AIMS To identify the frequency of cognitive and functional decline (CFD) among adults 50 years of age and older by a population-based study. METHODS Cognitive function was analyzed by the Mini-Mental State Examination, and the functional conditions were based on instrumental activities of daily living (IADL). Cases of CFD included individuals with cognitive decline and 2 or more compromised I...