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We develop a numerical method for simulation of incompressible viscous flows by integrating the technology of random vortex method with the core idea of Large Eddy Simulation (LES). Specifically, we utilize the filtering method in LES,…

Fluid Dynamics · Physics 2024-10-08 Zihao Guo , Zhongmin Qian

Adjoint methods have been the pillar of gradient-based optimization for decades. They enable the accurate computation of a gradient (sensitivity) of a quantity of interest with respect to all system's parameters in one calculation. When the…

Fluid Dynamics · Physics 2024-11-12 Defne E. Ozan , Luca Magri

Hybrid Reynolds-averaged Navier Stokes large eddy simulation (RANS LES) methods have become popular for simulation of massively separated flows at high Reynolds numbers due to their reduced computational cost and good accuracy. The current…

Fluid Dynamics · Physics 2021-02-19 Gaurav Kumar , Ashoke De , Harish Gopalan

Turbulent flows have historically presented formidable challenges to predictive computational modeling. Traditional numerical simulations often require vast computational resources, making them infeasible for numerous engineering…

Fluid Dynamics · Physics 2023-11-15 Han Gao , Xu Han , Xiantao Fan , Luning Sun , Li-Ping Liu , Lian Duan , Jian-Xun Wang

In this study, ensembles of experimental data are presented and utilized to compare and validate two models used in the simulation of variable density, compressible turbulent mixing. Though models of this kind (Reynolds Averaged Navier…

Fluid Dynamics · Physics 2022-03-07 Benjamin Musci , Britton Olson , Samuel Petter , Gokul Pathikonda , Devesh Ranjan

The main objective of this work is to develop a unified framework that can be used as a lens to quantitatively assess and augment a wide range of coarse-grained models of turbulence, viz. large eddy simulations (LES), hybrid…

Fluid Dynamics · Physics 2023-01-25 Aniruddhe Pradhan , Karthik Duraisamy

We discuss a possible theoretical interpretation of the self scaling property of turbulent flows (Extended Self Similarity). Our interpretation predicts that, even in cases when ESS is not observed, a generalized self scaling, must be…

chao-dyn · Physics 2016-08-31 R. Benzi , L. Biferale , S. Ciliberto , R. Tripiccione , M. V. Struglia

Computational fluid dynamics (CFD) is a useful tool for prediction of turbulence in aerodynamic and biomedical applications. The choice of appropriate turbulence models is key to reaching accurate predictions. The present investigation…

Fluid Dynamics · Physics 2018-03-13 Fardin Khalili , Peshala P. T. Gamage , Hansen A. Mansy

An extension to the classical FPV model is developed for transcritical real-fluid combustion simulations in the context of finite volume, fully compressible, explicit solvers. A double-flux model is developed for transcritical flows to…

Fluid Dynamics · Physics 2017-04-11 Peter C. Ma , Daniel T. Banuti , Jean-Pierre Hickey , Matthias Ihme

The Eulerian-Lagrangian approach based on Large-Eddy Simulation (LES) is one of the most promising and viable numerical tools to study turbulent dispersed flows when the computational cost of Direct Numerical Simulation (DNS) becomes too…

Fluid Dynamics · Physics 2017-06-02 Alessio Innocenti , Cristian Marchioli , Sergio Chibbaro

In this work, we propose using an ensemble Kalman method to learn a nonlinear eddy viscosity model, represented as a tensor basis neural network, from velocity data. Data-driven turbulence models have emerged as a promising alternative to…

Fluid Dynamics · Physics 2022-10-12 Xin-Lei Zhang , Heng Xiao , Xiaodong Luo , Guowei He

In this study, realizable algebraic Reynolds stress modeling based on the square root tensor [Phys. Rev. E \textbf{92}, 053010 (2015)] is further developed for extending its applicability to more complex flows. In conventional methods, it…

Fluid Dynamics · Physics 2019-11-13 Kazuhiro Inagaki , Taketo Ariki , Fujihiro Hamba

Extreme events play a crucial role in fluid turbulence. Inspired by methods from field theory, these extreme events, their evolution and probability can be computed with help of the instanton formalism as minimizers of a suitable action…

Fluid Dynamics · Physics 2015-10-28 Tobias Grafke , Rainer Grauer , Stephan Schindel

Linear stability analysis has proven to be a useful tool in the analysis of dominant coherent structures, such as the von K\'{a}rm\'{a}n vortex street and the global spiral mode associated with the vortex breakdown of swirling jets. In…

Fluid Dynamics · Physics 2016-08-24 Lothar Rukes , Christian Oliver Paschereit , Kilian Oberleithner

We consider a statistical limit of solutions to the compressible Navier--Stokes system in the high Reynolds number regime in a domain exterior to a rigid body. We investigate to what extent this highly turbulent regime can be modeled by an…

Analysis of PDEs · Mathematics 2022-02-09 Eduard Feireisl , Martina Hofmanova

The spatiotemporal dynamics of turbulent flows is chaotic and difficult to predict. This makes the design of accurate and stable reduced-order models challenging. The overarching objective of this paper is to propose a nonlinear…

Fluid Dynamics · Physics 2022-11-23 Alberto Racca , Nguyen Anh Khoa Doan , Luca Magri

We propose a physics-constrained machine learning method-based on reservoir computing- to time-accurately predict extreme events and long-term velocity statistics in a model of turbulent shear flow. The method leverages the strengths of two…

Fluid Dynamics · Physics 2021-04-14 Nguyen Anh Khoa Doan , Wolfgang Polifke , Luca Magri

Current design constraints have encouraged the studies of aeroacoustics fields around compressible jet flows. The present work addresses the numerical study of unsteady turbulent jet flows for aeroacoustic analyses of main engine rocket…

Fluid Dynamics · Physics 2022-12-26 Carlos Junqueira-Junior , Sami Yamouni , Joao Luiz F. Azevedo , William Wolf

Turbulent flows under transcritical conditions are present in regenerative cooling systems of rocker engines and extraction processes in chemical engineering. The turbulent flows and the corresponding heat transfer phenomena in these…

Fluid Dynamics · Physics 2017-12-08 Peter C. Ma , Xiang I. A. Yang , Matthias Ihme

We propose Echo State Networks (ESNs) to predict the statistics of extreme events in a turbulent flow. We train the ESNs on small datasets that lack information about the extreme events. We asses whether the networks are able to extrapolate…

Fluid Dynamics · Physics 2022-04-13 Alberto Racca , Luca Magri