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CTR events

Tea Seminar : Friday, November 9, 2018 - 4:30pm : Speaker(s): Dr. Nagi N. Mansour
Abtract:

Protecting a spacecraft during atmospheric entry is one of highest risk factors that needs to be mitigated during design of a space exploration mission. At entry speeds from space, air turns into high-temperature plasma, and spacecraft Thermal Protection Systems (TPS) are needed to protect the vehicle payload. Modern successful material architectures of spacecraft shields use a porous carbon fiber substrate impregnated with phenolic as an ablator material. In the lecture, efforts to build a Predictive Material Modeling framework for porous ablators from micro-scale to macro-scale will be pr... Read More

Bio:
Dr. Mansour is currently Chief division Scientist at the NASA Advanced Supercomputing division. He received his Ph.D. in Mechanical Engineering at Stanford in 1978 where he carried out one of the... Read More
Tea Seminar : Friday, October 19, 2018 - 4:30pm : Speaker(s): Dr. Dong Li
Abtract:

Turbulent flows laden with particles are widely encountered in a great number of natural physical processes and in a host of industrial and environmental applications. In these flows there exist complex interactions between inertial particles, flow turbulence and heat transfer, many of which have not yet been adequately investigated and still remain open questions. In this talk, we will present the results of direct numerical simulations of particle-laden spatially developing turbulent boundary layer flows, using a two-way coupled Eulerian-Lagrangian approach. The main focus of this work is... Read More

Bio:
Dr. Dong Li obtained his PhD degree in Power Engineering and Engineering Thermophysics from Zhejiang University in 2016. Before joining CTR, he was a Postdoctoral Researcher at Zhejiang University.... Read More
Tea Seminar : Friday, October 5, 2018 - 4:30pm : Speaker(s): Dr. Armin Zare
Abtract:

This talk describes how to account for second-order statistics of turbulent flows using low-complexity stochastic dynamical models based on the linearized Navier-Stokes (NS) equations. The complexity is quantified by the number of degrees of freedom in the linearized evolution model that are directly influenced by stochastic excitation sources. For the case where only a subset of correlations are known, we develop a framework to complete unavailable second-order statistics in a way that is consistent with linearization around turbulent mean velocity. In general, white-in-time stochastic for... Read More

Bio:
Dr. Armin Zare received his B.Sc. degree in Electrical Engineering from Sharif University of Technology, Tehran, Iran, in 2010, and his Ph.D. degree in Electrical Engineering from the University of... Read More
Tea Seminar : Friday, September 7, 2018 - 4:30pm : Speaker(s): Mr. Chang-Hsin Chen
Abtract:

The interaction of turbulence with shock waves, while very common in nature and engineering systems, is a very difficult problem from a theoretical, numerical and experimental perspective. A main challenge arise from the two-way coupling between the shock and turbulence which occurs at a wide range of scales in time and space. The focus of this work is on the fundamental understanding of these shock-turbulence interactions (STI) at high turbulence intensities with high-fidelity direct numerical simulations (DNS) that fully resolve the shock. The numerical study is guided by novel theoretica... Read More

Bio:
Mr. Chang-Hsin Chen is an PhD Candidate in the Department of Aerospace Engineering at Texas A&M University working under the supervision of Professor Donzis. He received both his BS and MS from... Read More
Tutorial : Friday, June 29, 2018 - 4:00pm : Speaker(s): Javier Urzay
Abtract:

TBA

Summer Program : Sunday, June 24, 2018 - 9:00am : Speaker(s): Parviz Moin, Director of Center for Turbulence Research
Abtract:

 

 The Center for Turbulence Research invites applications for participation in its 17th biennial Summer Program. The objective of the Summer Program is to promote development and evaluation of new ideas in fluid mechanics with emphasis on turbulent flows. It is expected that the novel concepts and preliminary results generated during the Summer Program will be of sufficiently high caliber to lead to journal publications and to provide grounds for opening new lines of research in the participants' home institutions. 

In recent years a significant numb... Read More

Tea Seminar : Friday, June 8, 2018 - 4:30pm : Speaker(s): Mr. Nicholas Burali
Abtract:

The flamelet-based chemistry tabulation technique is a popular reduced-order model for non-premixed turbulent flames. In this approach, the one-dimensional flamelet equations are solved, and thermo-chemical quantities are tabulated with respect to the mixture fraction and either its scalar dissipation rate or a progress variable. In generating the individual flamelets to populate the chemical table, the correct choice of the species Lewis numbers plays an important role. Experimental observations have shown that, in turbulent non-premixed jet flames, the effect of turbulent transport on the... Read More

Bio:
Mr. Nicholas Burali is a PhD Candidate in Mechanical Engineering at the California Institute of Technology. He received his BS (2010) and MS (2013), both cum laude, from Sapienza University of Rome... Read More
Tea Seminar : Friday, May 18, 2018 - 4:30pm : Speaker(s): Dr. Immanuvel Paul
Abtract:
Fractal-grid-generated turbulence has gained considerable attention in the past decade owing to its novel unique characteristics including the nonequilibrium energy cascade present in the near field. This talk will present direct numerical simulation results of turbulence generated by a simplified fractal grid called a square grid-element.
                     
This talk consists of three parts. The first part focuses on the small-scale dynamics of grid-element turbulence. Specifically, the generating... Read More
Bio:
Dr. Immanuvel Paul obtained his PhD from Imperial College London in May 2017. He has been working on fractal-grid-generated turbulence, fine-scale structure of fluid and scalar turbulence, numerical... Read More
Tea Seminar : Friday, May 4, 2018 - 4:30pm : Speaker(s): Dr. Xiaojue Zhu
Abtract:

In this talk, Dr. Zhu will present "the newest results" on fully developed Rayleigh-Bénard turbulence. For the first time in numerical simulations we find the transition to the ultimate regime, namely at Ra*= 10^13. We reveal how the emission of thermal plumes enhances the global heat transport, leading to a steeper increase of the Nusselt number than the classical Malkus scaling. Beyond the transition, the temperature profiles are only locally logarithmic, namely within the regions where plumes are emitted, and where the local Nusselt number has an effective scaling exponent of 0.38 with r... Read More

Bio:
Dr. Xiaojue Zhu obtained his PhD in February 2018 from the Physics of Fluids Group at the University of Twente in the Netherlands. He is currently a postdoctoral researcher in the same group. His... Read More
Tea Seminar : Friday, April 27, 2018 - 4:30pm : Speaker(s): Dr. Adrian Lozano-Duran
Abtract:

At first sight, walls appear as the most relevant ingredient in turbulence confined or limited by solid surfaces, and it seems plausible to assume that they should be the origin and organizing agent of wall-bounded turbulence.  Consequently, many efforts have been devoted to understand the structure of turbulence in the vicinity of walls.  Particularly interesting is the region within the so-called log-layer, where most of the dissipation resides in the asymptotic limit of infinite Reynolds number.

In the present work, the role of the wall and mean momentum transfer on the outer laye... Read More

Bio:
Dr. Adrian Lozano-Duran received his PhD from the Technical University of Madrid in 2015 at the Computational Fluid Mechanics Lab. headed by Professor Jiménez. His main research has focused on... Read More

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