CTR events

The COOLFluiD (Computational Object Oriented Libraries for Fluid Dynamics) project, which started in 2002 as a joint effort between the Von Karman Institute for Fluid Dynamics (VKI) and the Center for mathematical Plasma Astrophysics (CmPA) at the University of Leuven (KUL), has led to the development of a world-class open source platform for HPC and multi-physics modelling. Within this framework, research efforts have been devoted particularly to the modeling of space re-entry aerothermodynamics and magnetized plasmas. The former includes the development of models/algorithms for simulating... Read More

In this talk we investigate amplifying behavior of small perturbations about Reynolds-averaged Navier-Stokes solutions of high-speed turbulent jets using input-output (I/O) analysis.  Inspired by control theory in electrical engineering, our method investigates how input forcing (jet turbulence) leads to output noise.  Singular value decomposition of the resolvent of the linearized Navier-Stokes equations forms an orthonormal set of I/O mode pairs, sorted in descending order by the magnitude of the corresponding singular values.  In this way we find that the input modes capture coherent str... Read More

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

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

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

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

TBA

 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

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