CAVS / Current Research / Computational Fluid Dynamics / Aeroacoustics and LES

Aeroacoustics and LES

Led by Dr. Adrian Sescu, a CAVS research group is focusing on fundamental research on topics in aeroacoustics, transition in boundary layers, and synthetic turbulence modeling for both large and direct numerical simulations. Current research areas include:

Prediction of nonlinear waves from jet noise

This research is motivated by observations that the noise radiated from plumes of liftoff vehicles is very intense. The CAVS research team employs a hybrid acoustic technique, in which the Navier-Stokes equations in the acoustic region is coupled with a non-linear Euler solver for acoustic propagation. The source term in the Euler equations is input using a penalization technique.

Aeroacoustics and LES graph 1
Aeroacoustics and LES graph 2

Coupled LES and stochastic modeling for jet noise

In collaboration with Tohoku University, CAVS seeks to utilize very large eddy simulations and stochastic modeling to approximate the acoustic spectra at the level of direct numerical simulation, where the LES accounts for low frequency noise, while the stochastic model provides the high frequency content.

Control of boundary layer instabilities and transition

Based on wall transpiration, deformation and cooling, various control strategies are utilized to reduce the energy of boundary layer streaks, and to ultimately minimize the skin friction drag.

Aeroacoustics and LES graph 3
Aeroacoustics and LES graph 4

Synthetic turbulence

CAVS is developing novel synthetic turbulence methods based on superpositions of distorted Hill’s vortices, aimed at imposing realistic turbulent inflow condition for LES and DNS. We are also using forcing sources to develop precursor LES methods for turbulent boundary layers.

References

  • Es-Sahli, O., Sescu, A., Afsar, M.Z., and Buxton, O.R.H. (2020) Investigation of wakes generated by fractal plates in the compressible regime using large-eddy simulations, Physical of Fluids, Vol. 32, pp. 105106.
  • Haywood, J., Sescu, A. and Adkins, K. (2020) Large eddy simulation study of the humidity variation in the shadow of a large wind farm, Wind Energy, Vol. 23, pp. 423-431.
  • Colby, H., Sescu, A., Afsar, M., Collins, E. and Azarpeyvand, M. (2020) Passive Noise Control Strategies for Jets Exhausting over Flat Surfaces: an LES Study, AIAA Paper 2020-2552, AIAA Aviation Conference.
  • Afsar, M.Z., Sescu, A. and Sassanis, V. (2019) Effect of non-parallel mean flow on the acoustic spectrum of heated supersonic jets: Explanation of "jet quietening", Physics of Fluids, Vol. 31, pp. 105107.
  • Haywood, J. and Sescu, A. (2019) A Control Forced Concurrent Precursor Method for LES Inflow, Flow, Turbulence and Combustion, Vol. 102, pp. 849-864.
  • Sescu, A., Alaziz, R. and Afsar, M.Z. (2019) Effect of Wall Transpiration and Heat Transfer on Nonlinear Gortler Vortices in High-speed Boundary Layers, AIAA Journal, AIAA Journal, Vol. 576, pp. 1159-1171.
  • Afsar, M.Z., Sescu, A. and Leib, S.J. (2019) Modeling and prediction of the peak radiated sound in sub-sonic axisymmetric air jets using acoustic analogy based asymptotic analysis, Philosophical Transactions A, Vol. 377, Issue 2159.
  • Haywood, J.S., Sescu, A., Bhushan, S., Foster, J. and Farthing, M. (2018) Towards a More Realistic Triple Hill's Vortex Synthetic Method for LES of Wall Bounded Flows, AIAA Paper 2018-0837, AIAA Scitech Forum, Kissimmee, FL.
  • Sawaya. J., Yassir, S., Sassanis, V. and Sescu, A. and Visbal M. (2018) Assessment of the impact of two-dimensional wall deformations’ shape on high-speed boundary layer disturbances, AIAA Journal, Vol. 56, pp. 4787-4800.
  • Sescu, A. and Afsar, M. (2018) Hampering Gortler vortices via optimal control in the framework of nonlinear boundary region equations, Journal of Fluid Mechanics, Vol. 848, p. 5-41.
  • Sescu, A., Taoudi, L. and Afsar, M. (2018) Iterative control of Gortler vortices via local wall deformations, Theoretical and Computational Fluids Dynamics, Vol. 32, pp. 63-72.
  • Sassanis, V., Sescu, A., Collins, E.M., Harris, R. and Luke, A.E. (2017) A Hybrid Approach for Nonlinear Computational Aeroacoustics Predictions, International Journal for Computational Fluid Dynamics, Vol. 31, pp. 1-20.
  • Goldstein, M., Sescu, A., Duck, P. and Choudhari, M. (2016) Nonlinear wakes behind a row of elongated roughness elements, Journal of Fluid Mechanics, Vol. 796, pp. 516-557.
  • Harris, R., Collins, E.M., Luke, A.E., Sescu, A., Strutzenberg, L.L. and West, J.S. (2016) Coupled Overset Unstructured Discontinuous Galerkin Method for Launch Environment Acoustics Prediction, AIAA Journal, Vol. 54, pp. 1932-1952.