@article{towne_dawson_bres_lozano-duran_saxton-fox_parthasarathy_jones_biler_yeh_patel_et al._2023, title={A Database for Reduced-Complexity Modeling of Fluid Flows}, ISSN={["1533-385X"]}, DOI={10.2514/1.J062203}, abstractNote={ We present a publicly accessible database specifically designed to aid in the conception, training, demonstration, evaluation, and comparison of reduced-complexity models for fluid mechanics. Availability of high-quality flow data is essential for all of these aspects of model development for both data-driven and physics-based methods. The current database is unique in that it has been curated with this need in mind. The database contains time-resolved data for six distinct datasets: a large eddy simulation of a turbulent jet, direct numerical simulations of a zero-pressure-gradient turbulent boundary layer, particle-image-velocimetry measurements for the same boundary layer at several Reynolds numbers, direct numerical simulations of laminar stationary and pitching flat-plate airfoils, particle-image-velocimetry and force measurements of an airfoil encountering a gust, and a large eddy simulation of the separated, turbulent flow over an airfoil. These six cases span several key flow categories: laminar and turbulent, statistically stationary and transient, tonal and broadband spectral content, canonical and application-oriented, wall-bounded and free-shear flow, and simulation and experimental measurements. For each dataset, we describe the flow setup and computational/experimental methods, catalog the data available in the database, and provide examples of how these data can be used for reduced-complexity modeling. All data can be downloaded using a browser interface or Globus. Our vision is that the common testbed provided by this database will aid the fluid mechanics community in clarifying the distinct capabilities of new and existing methods. }, journal={AIAA JOURNAL}, author={Towne, Aaron and Dawson, Scott T. M. and Bres, Guillaume A. and Lozano-Duran, Adrian and Saxton-Fox, Theresa and Parthasarathy, Aadhy and Jones, Anya R. and Biler, Hulya and Yeh, Chi-An and Patel, Het D. and et al.}, year={2023}, month={May} }
 @inproceedings{patel_yeh_2023, title={Modal analysis for three-dimensional instability coupling mechanisms in turbulent wake flows over an airfoil}, DOI={10.2514/6.2023-1987}, abstractNote={We investigate the instability coupling mechanisms between the shear layer and the wake for turbulent separated flows over a NACA 0012 airfoil at Reynolds number of $23, 000$ with the use of spectral proper orthogonal decomposition and the bispectral mode decomposition. The datasets are obtained from the large-eddy simulations in two configurations: two-dimensional (2D) and three-dimensional (3D) with spanwise periodicity. The 2D flow is characterized by the periodic vortex shedding from the shear layer and the convection of these vortices into the wake, resulting in a frequency spectrum that peaks at the natural shedding frequency and its harmonics. On the contrary, the 3D flow exhibits distinctive frequency contents for the shear layer and the wake with the presence of dominant frequency associated with the coupled coherent structures. Spectral proper orthogonal decomposition (SPOD) is used to examine the spatial and temporal coherent fluctuation for both the flows. The SPOD is also performed with a weighting matrix that highlights the shear layer where certain frequencies higher than dominant shedding frequency are promoted which marks the the shear layer physics in the 3D flow. The coupled coherent structures in the 2D and 3D flows have different self-driving mechanisms. The coupling mechanism in the 2D flow is observed to be governed largely by the interactions between the fundamental shedding frequency and its harmonics. For the 3D flow the self-driving mechanism that supports the emergence of coupled coherent structures is mainly attributed to mean flow interaction. We believe the identification of active paths of triadic interactions can serve as a building block toward the design of active flow control.}, booktitle={AIAA SCITECH 2023 Forum}, publisher={American Institute of Aeronautics and Astronautics}, author={Patel, Het D. and Yeh, Chi-An}, year={2023}, month={Jan} }
 @unpublished{towne_dawson_brès_lozano-durán_saxton-fox_parthasarathy_jones_biler_yeh_patel_et al._2022, title={A Database for Reduced-Complexity Modeling of Fluid Flows}, journal={arXiv e-prints}, author={Towne, Aaron and Dawson, Scott T. M. and Brès, Guillaume A. and Lozano-Durán, Adrián and Saxton-Fox, Theresa and Parthasarathy, Aadhy and Jones, Anya R. and Biler, Hulya and Yeh, Chi-An and Patel, Het D. and et al.}, year={2022}, month={Jun} }