Current Seminars - Future Seminars - Past Seminars Computational Applied Math - Computational Biology - Operations Research - Quantitative Finance - Statistics Computational Applied Math Wednesday, November 30, 2011 Time: 1:00PM-2:00PM Location: Seminar Room 1-122 Speaker: Professor Hyunsun Lee, Department of Mathematics, Florida State University, Tallahassee, FL, USA Abstract: An acoustic analogy using decomposition of the Lighthill source term to ten sub-terms is discussed in the light of a high-fidelity numerical simulation of a subsonic jet, at Mach number 0.9 and Reynolds number 100,000, with a baseline nozzle (SMC000) as a benchmark problem. These sub-terms consist of density, velocity, vorticity and dilatation fields, presenting their reciprocal non-linear interactions. To understand aerodynamic noise generation mechanism, intrinsic links between turbulence and emitted sound waves, such as cross-correlation function, are necessary. This causality method is directly adopted to the LES data to identify fundamental noise sources by calculating the cross-correlation between each spatial sub-term in near field and acoustic pressure fluctuation at a far field position, showing its contribution on the noise generation. Three principal noise production terms, related to Laplacian of turbulence kinetic energy and divergence of Lamb vector, are witnessed and interpreted, showing encouraging agreement with previous predictions. As a future work, the observation can be extended on SMC006 chevron jet nozzle configuration, possibly leading us to characterize the structure by comparing the correlation profiles with those of SMC000. Furthermore, this study is expected to shed light on assessing a better understanding and prediction on other sound control devices. Friday, October 21, 2011, Time: 11:00-12:00PM Location: Seminar Room 1-122 Abstract: In this talk, I will introduce the notion of splines over T-meshes and present some recent advances on the theory and applications of splines over T-meshes. The applications in Geometric Modelling and Isogeometric Analysis (IGA) are emphasized.
Speaker: Dr. Rajeev Jaiman, Director of CFD Development at Altair Engineering, Inc. Title: Stable and Accurate Techniques for Transient Multiphysics Simulations Abstract: This presentation summarizes recent results obtained in the development of a novel numerical treatment of coupled multiphysics problems, with emphasis on the simulation of transient fluid-structure interaction (FSI) applications. The talk will begin with the example problems ranging from the propagation of shocks and blast waves along deformable structures, flutter instability, aeroelasticity-driven failure events in solid propellant rockets, offshore marine risers and pipelines, large scale wind turbines, nuclear energy, bio-medical and many more. The talk will focus on two aspects of the on-going research in the area of multiphysics simulations: (i) the development of an accurate scheme used to transfer fluid-induced loads across non-matching discretized interfaces; and (ii) the formulation and implementation of new stable and accurate coupling schemes between fluid and structural solvers. Beyond a presentation of the load transfer and coupling schemes, the talk will include results of a detailed comparative study between the proposed methods and existing schemes. These comparative assessments are based on a set of FSI applications of increasing complexity involving flat and curved fluid interfaces. The talk will conclude with a brief reporting on the successful applications of the new methods and their impact on the current state of the art in computational mechanics.
No seminars scheduled No seminars scheduled Wednesday, February 29, 2012, Time from 2:00PM -3:00PM, Location: Math Tower, Seminar Room 1-122
This paper discusses properties of a Doubly Stochastic Poisson Process (DSPP) where the intensity process belongs to a class of affine diffusions. For any intensity process from this class we derive an analytical expression for probability distribution functions of the corresponding DSPP. A specification of our results is provided in a particular case where the intensity is given by one-dimensional Feller process and its parameters are estimated by Kalman filtering for high frequency transaction data.
No seminars scheduled
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