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Articles 1 - 9 of 9
Full-Text Articles in Mechanical Engineering
A Novel Approach To Evaluating Compact Finite Differences And Similar Tridiagonal Schemes On Gpu-Accelerated Clusters, Ashwin Trikuta Srinath
A Novel Approach To Evaluating Compact Finite Differences And Similar Tridiagonal Schemes On Gpu-Accelerated Clusters, Ashwin Trikuta Srinath
All Theses
Compact finite difference schemes are widely used in the direct numerical simulation of fluid flows for their ability to better resolve the small scales of turbulence. However, they can be expensive to evaluate and difficult to parallelize. In this work, we present an approach for the computation of compact finite differences and similar tridiagonal schemes on graphics processing units (GPUs). We present a variant of the cyclic reduction algorithm for solving the tridiagonal linear systems that arise in such numerical schemes. We study the impact of the matrix structure on the cyclic reduction algorithm and show that precomputing forward reduction …
Using Star-Ccm+ To Evaluate Multi-User Collaboration In Cfd, Kasey Johnson Webster
Using Star-Ccm+ To Evaluate Multi-User Collaboration In Cfd, Kasey Johnson Webster
Theses and Dissertations
The client-server architecture of STAR-CCM+ allows multiple users to collaborate on a simulation set-up. The effectiveness of collaboration with this architecture is tested and evaluated on five models. The testing of these models is a start to finish set-up of an entire simulation excluding computational time for generating mesh and solving the solution. The different models have distinct differences which test every operation that would be used in a general CFD simulation. These tests focus on reducing the time spent preparing the geometry to be meshed, including setting up for a conformal mesh between multiple regions in conjugate heat transfer …
Experimental And Numerical Investigation Of Heat Transfer In Cnt Nanofluids
Experimental And Numerical Investigation Of Heat Transfer In Cnt Nanofluids
Faculty of Engineering University of Malaya
Nanofluids with their enhanced thermal conductivity are believed to be a promising coolant in heat transfer applications. In this study, carbon nanotube (CNT) nanofluids of 0.01wt%, stabilised by 1.0wt% gum arabic were used as a cooling liquid in a concentric tube laminar flow heat exchanger. The flow rate of cold fluid varied from 10 to 50g/s. Both experimental and numerical simulations were carried out to determine the heat transfer enhancement using CNT nanofluids. Computational fluid dynamics (CFD) simulations were carried out using Fluent v 6.3 by assuming single-phase approximation. Thermal conductivity, density and rheology of the nanofluid were also measured …
Three Dimensional Simulations Of Tornado Sheltering Effect Of Man-Made Structures, Piotr Gorecki
Three Dimensional Simulations Of Tornado Sheltering Effect Of Man-Made Structures, Piotr Gorecki
Graduate Theses and Dissertations
A three dimensional computational fluid dynamics (CFD) model was utilized to investigate tornado-like vortex interactions with wide man-made structures. The tornado-like wind profile was approximated using Rankine vortex model. By utilizing the CFD model, it was explained why tornadoes exhibit less damage on leeward side of large structures. During the preliminary stage of this study, a perpendicular vortex-prism interaction was analyzed. The prism height and the length were equal to the vortex core radius. The prism was also 12 times wider than the vortex core radius. During the vortex-prism interaction, the near-ground portion of the vortex was blocked by the …
Aerodynamics Inside A Rapid Compression Machine, Gaurav Mittal, Chih-Jen Sung
Aerodynamics Inside A Rapid Compression Machine, Gaurav Mittal, Chih-Jen Sung
Dr. Gaurav Mittal
The aerodynamics inside a rapid compression machine after the end of compression is investigated using planar laser-induced fluorescence (PLIF) of acetone. To study the effect of reaction chamber configuration on the resulting aerodynamics and temperature field, experiments are conducted and compared using a creviced piston and a flat piston under varying conditions. Results show that the flat piston design leads to significant mixing of the cold vortex with the hot core region, which causes alternate hot and cold regions inside the combustion chamber. At higher pressures, the effect of the vortex is reduced. The creviced piston head configuration is demonstrated …
Vortex Formation In A Rapid Compression Machine: Influence Of Physical And Operating Parameters, Gaurav Mittal, Mandhapati Raju, Chih-Jen Sung
Vortex Formation In A Rapid Compression Machine: Influence Of Physical And Operating Parameters, Gaurav Mittal, Mandhapati Raju, Chih-Jen Sung
Dr. Gaurav Mittal
The performance of a rapid compression machine (RCM) with a creviced piston is assessed over a range of operating conditions through computational fluid dynamics simulations with systematic demonstration of the effects of compressed gas pressure, temperature, stroke length, and clearance on altering vortex formation and temperature homogeneity inside the reaction chamber. Simulated results show that as compressed gas pressure is reduced, the temperature homogeneity deteriorates due to the combined effect of thicker boundary layer and increased flow velocities. A further optimization of the creviced piston geometry is then required to completely suppress the roll-up vortex. Stroke length and clearance volume …
Meshless Direct Numerical Simulation Of Turbulent Incompressible Flows, Andres Vidal Urbina
Meshless Direct Numerical Simulation Of Turbulent Incompressible Flows, Andres Vidal Urbina
Electronic Theses and Dissertations
A meshless direct pressure-velocity coupling procedure is presented to perform Direct Numerical Simulations (DNS) and Large Eddy Simulations (LES) of turbulent incompressible flows in regular and irregular geometries. The proposed method is a combination of several efficient techniques found in different Computational Fluid Dynamic (CFD) procedures and it is a major improvement of the algorithm published in 2007 by this author. This new procedure has very low numerical diffusion and some preliminary calculations with 2D steady state flows show that viscous effects become negligible faster that ever predicted numerically. The fundamental idea of this proposal lays on several important inconsistencies …
Analytical And Numerical Validation Of Nozzle Spray Measurement Data Obtained From A Newly Developed Production System, Iddrisu Seidu
Analytical And Numerical Validation Of Nozzle Spray Measurement Data Obtained From A Newly Developed Production System, Iddrisu Seidu
ETD Archive
A newly developed production test stand for measuring the spray angle of a pressure swirl atomizer was constructed and used to measure a product line of these pressure swirl atomizers -- the macrospray atomizer. This new test stand, utilizing constant temperature hot wire anemometers, captures the spray angle data based on the voltage drop the hot wire probes see as they traverse the spray cone of the atomizer and as fluid droplets impinge upon the wire. Datasets acquired from the experiments are compared and correlated with computational fluid dynamics (CFD) simulation data. In addition, angles obtained from another type of …
Air Flow And Rain Water Penetration Analysis On Generator Enclosures Using Cfd Simulations, Sasanka Andawatta Kankanamge
Air Flow And Rain Water Penetration Analysis On Generator Enclosures Using Cfd Simulations, Sasanka Andawatta Kankanamge
All Graduate Theses, Dissertations, and Other Capstone Projects
Rain water penetration testing on power generator units requires a number of complicated procedures, requiring many resources. As such, a Computational Fluid Dynamics (CFD) tool, "FloEFD for Creo" is used to study the water penetration behavior on a OM924 diesel power generator enclosure in a computational environment. First, the three governing equations in fluid dynamics are derived and explained using simple methods. Next, behavior of rain water droplets upon impact is briefly discussed. Air velocity, volumetric flow rate and static pressure drop were measured physically in the OM924 generator enclosure. Then, a CFD model for the OM924 enclosure was developed …