Timothy T. Aiken received a Ph.D. in Aerospace Engineering Sciences in 2023 from the University of Colorado, Boulder, where he also completed a M.S. in 2022. He previously earned a B.S. in Aerospace Engineering from the University of Kansas in 2019. Tim is currently a postdoctoral research associate at the Center for National Security Initiatives at the University of Colorado, Boulder.
Tim specializes in computational modeling of hypersonic flows, sensitivity analysis, and uncertainty quantification, aiming to improve the accuracy and characterization of the complex physical models used in hypersonic vehicle design.
Nonequilibrium Gas and plasma dynamics:聽One of the defining features of hypersonic flight is the presence of strong shock waves. These shocks cause the gas around the vehicle to dissociate and, at higher speeds, ionize, forming plasma. Accurately modeling dissociation is essential for accurately predicting heat transfer, while ionization plays a key role in understanding communication blackout and the radiative signature of the vehicle. Tim specializes in studying the nonequilibrium chemical kinetics of hypersonic flows, using state-resolved models that precisely capture the complex processes occurring in the gas. These detailed models provide valuable insights into the underlying nonequilibrium dynamics and help assess and improve the approximations made in the reduced-order models used for hypersonic vehicle development.
Sensitivity analysis and uncertainty quantification:聽When working with complex simulations, it's important to quantify the impact of uncertainties in model parameters. Tim applies sensitivity analysis and uncertainty quantification to systematically assess how uncertainties in input parameters affect the reliability of model predictions. This process helps identify the most influential parameters, allowing us to focus efforts on refining those areas of the model that will most improve overall accuracy and reliability.
Turbulent flows:聽Predicting heat transfer and skin friction in turbulent hypersonic flows is critical for vehicle design. Tim has investigated the performance of Reynolds Averaged Navier-Stokes (RANS) models in predicting these quantities over flat plates immersed in hypersonic flow, helping to advance the understanding of how these commonly-employed models perform in challenging high-speed environments.