No description available.

No description available.

The unsteady two-dimensional flow around an array of circular cylinders submerged in a uniform onset flow is analyzed. The fluid is taken to be viscous and incompressible. The array of cylinders consists of two horizontal rows extending to infinity in the upstream and downstream directions. The center-to-center distance between adjacent cylinders is a constant. The Biot-Savart law of induced velocities is used to determine the velocity field due to the free vorticity in the surrounding fluid and the bound vorticity distributed on the surface of each cylinder. The bound vorticity is needed to enforce the no-penetration condition and to account for the production of free vorticity in the solid surfaces. It is governed by a Fredholm integral equation of the second kind. This equation is solved by numerical techniques. The transport of free vorticity in the flow field is governed by the vorticity transport equation. This equation is discretized for a control volume and is solved numerically. Advantage is taken of spatially periodic boundary conditions in the flow direction. This reduces the computational domain to a rectangular region surrounding a single circular cylinder, but necessitates use of a non-orthogonal grid. In order to test the numerical techniques, the simpler case of unsteady flow over a single circular cylinder at various Reynolds numbers if first considered. Results compare favorably with previous experimental and numerical data. Three cases for Reynolds numbers of 10², 10³, and 10⁴ are presented for the array of cylinders. The center-to-center distance is fixed at three diameters. The time development of constant vorticity contours as well as drag, lift, and moment coefficients are shown for each Reynolds number. The motion of stagnation and separation points with time is also given. It is found that the drag for a cylinder in the array may be as low as five percent of that for flow over a single cylinder at the same Reynolds number.

No description available.

Yim-Pan Chui. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 126-132). / Abstracts in English and Chinese. / Abstract --- p.ii / Acknowledgments --- p.v / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Introduction to Collaborative Virtual Environments --- p.1 / Chapter 1.2 --- Barriers to Resource Management and Optimization --- p.3 / Chapter 1.3 --- Thesis Contributions --- p.5 / Chapter 1.4 --- Application of this Research Work --- p.6 / Chapter 1.5 --- Thesis Organization --- p.6 / Chapter 2 --- Resource Optimization - Intelligent Server Partitioning --- p.9 / Chapter 2.1 --- Introduction --- p.9 / Chapter 2.2 --- Server Partitioning --- p.13 / Chapter 2.2.1 --- Related Works --- p.15 / Chapter 2.2.2 --- Global Optimization Approaches --- p.17 / Chapter 2.3 --- Hybrid Genetic Algorithm Paradigm --- p.17 / Chapter 2.3.1 --- Drawbacks of traditional GA --- p.18 / Chapter 2.3.2 --- Problem Modeling --- p.19 / Chapter 2.3.3 --- Discussion --- p.24 / Chapter 2.4 --- Results --- p.25 / Chapter 2.5 --- Concluding Remarks --- p.28 / Chapter 3 --- Dynamic State Management - Dead Reckoning of Attitude --- p.32 / Chapter 3.1 --- Introduction to Dynamic State Management --- p.32 / Chapter 3.2 --- The Dead Reckoning Approach --- p.35 / Chapter 3.3 --- Attitude Dead Reckoning by Quaternion --- p.37 / Chapter 3.3.1 --- Modeling of the Paradigm --- p.38 / Chapter 3.3.2 --- Prediction Step --- p.39 / Chapter 3.3.3 --- Convergence Step --- p.40 / Chapter 3.3.4 --- Overall Algorithm --- p.46 / Chapter 3.4 --- Results --- p.47 / Chapter 3.5 --- Conclusion --- p.51 / Chapter 4 --- Polynomial Attitude Extrapolation --- p.52 / Chapter 4.1 --- Introduction --- p.52 / Chapter 4.2 --- Related Works on Kalman Filtering --- p.53 / Chapter 4.3 --- Historical Propagation of Quaternion --- p.54 / Chapter 4.3.1 --- Cumulative Extrapolation --- p.54 / Chapter 4.3.2 --- Method I. Vandemonde Approach --- p.55 / Chapter 4.3.3 --- Method II. Lagrangian Approach --- p.58 / Chapter 4.4 --- History-Based Attitude Management --- p.60 / Chapter 4.4.1 --- Multi-order Prediction --- p.60 / Chapter 4.4.2 --- Adaptive Attitude Convergence --- p.63 / Chapter 4.4.3 --- Overall Algorithm --- p.67 / Chapter 4.5 --- Results --- p.69 / Chapter 4.6 --- Conclusion --- p.77 / Chapter 5 --- Forward Difference Approach on State Estimation --- p.78 / Chapter 5.1 --- Introduction --- p.78 / Chapter 5.2 --- Positional Forward Differencing --- p.79 / Chapter 5.3 --- Forward Difference on Quaternion Space --- p.80 / Chapter 5.3.1 --- Attitude Forward Differencing --- p.83 / Chapter 5.3.2 --- Trajectory Blending --- p.84 / Chapter 5.4 --- State Estimation --- p.86 / Chapter 5.5 --- Computational Efficiency --- p.87 / Chapter 5.6 --- Results --- p.88 / Chapter 5.7 --- Conclusion --- p.96 / Chapter 6 --- Predictive Multibody Kinematics --- p.98 / Chapter 6.1 --- Introduction --- p.98 / Chapter 6.2 --- Dynamic Management of Multibody System --- p.100 / Chapter 6.2.1 --- Multibody Representation --- p.100 / Chapter 6.2.2 --- Paradigm Overview --- p.101 / Chapter 6.3 --- Motion Estimation by Joint Extrapolation --- p.102 / Chapter 6.3.1 --- Individual Joint Extrapolation --- p.102 / Chapter 6.3.2 --- Forward Propagation of Joint State --- p.104 / Chapter 6.3.3 --- Pose Correction --- p.107 / Chapter 6.4 --- Limitations on Predictive Articulated State Management --- p.108 / Chapter 6.5 --- Implementation and Results --- p.109 / Chapter 6.6 --- Conclusion --- p.112 / Chapter 7 --- Complete System Architecture --- p.113 / Chapter 7.1 --- Server Cluster Model --- p.113 / Chapter 7.1.1 --- Peer-Server Systems --- p.114 / Chapter 7.1.2 --- Server Hierarchies --- p.114 / Chapter 7.2 --- Multi-Level Resource Management --- p.115 / Chapter 7.3 --- Aggregation of State Updates --- p.116 / Chapter 7.4 --- Implementation Issues --- p.117 / Chapter 7.4.1 --- Medical Visualization --- p.117 / Chapter 7.4.2 --- Virtual Walkthrough Application --- p.118 / Chapter 7.5 --- Conclusion --- p.119 / Chapter 8 --- Conclusions and Future directions --- p.121 / Chapter 8.1 --- Conclusion --- p.121 / Chapter 8.2 --- Future Research Directions --- p.122 / Chapter A --- Quaternion Basis --- p.124 / Chapter A.1 --- Basic Quaternion Mathematics --- p.124 / Chapter A.2 --- The Exponential and Logarithmic Maps --- p.125 / Bibliography --- p.126

Abstract not available

No description available.

Thesis. 1975. Ph.D.--Massachusetts Institute of Technology. Dept. of Nuclear Engineering. / Includes bibliographical references. / by Owen L. Deutsch. / Ph.D.

Super-tall buildings located in high velocity wind regions are highly vulnerable to large lateral loads. Designing for these structures must be done with great engineering judgment by structural professionals. Present methods of evaluating these loads are typically by the use of American Society of Civil Engineers 7-10 standard, field measurements or scaled wind tunnel models. With the rise of high performance computing nodes, an emerging method based on the numerical approach of Computational Fluid Dynamics has created an additional layer of analysis and loading prediction alternative to conventional methods. The present document uses turbulence modeling and numerical algorithms by means of Reynolds-averaged Navier-Stokes and Large Eddy Simulation equations applied to a square prismatic prototype structure in which its dynamic properties have also been investigated. With proper modeling of the atmospheric boundary layer flow, these numerical techniques reveal important aerodynamic properties and enhance flow visualization to structural engineers in a virtual environment. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection

In this work, we develop an extension of the generalized Fourier transform for exterior domains due to T. Ikebe and A. Ramm for all dimensions n>2 to study the Laplacian, and fractional Laplacian operators in such a domain. Using the harmonic extension approach due to L. Caffarelli and L. Silvestre, we can obtain a localized version of the operator, so that it is precisely the square root of the Laplacian as a self-adjoint operator in L2 with DIrichlet boundary conditions. In turn, this allowed us to obtain a maximum principle for solutions of the dissipative two-dimensional quasi-geostrophic equation the exterior domain, which we apply to prove decay results using an adaptation of the Fourier Splitting method of M.E. Schonbek. / by Leonardo Kosloff. / Thesis (Ph.D.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.