Christopher Williams

All Publications

• Reaction-induced departures from continuum Navier-Stokes turbulence. Proceedings of the National Academy of Sciences of the United States of America Williams, C. T., McMullen, R. M., Gallis, M. A. 2025; 122 (40): e2508608122

  Abstract

  Reactive hydrodynamic turbulence is an inherently multiscale phenomenon, characterized by the separation between energy-containing, viscous, and molecular length and time scales. The separation between the viscous scale (the Kolmogorov scale) and the molecular mean free path ostensibly justifies a macroscopic description of reactive turbulence via the Navier-Stokes (NS) equations. However, here we use molecular-level simulations to demonstrate that exothermic bimolecular reactions can cause the NS description of turbulence to break down in the near-continuum regime. Sufficiently energetic heat-releasing reactive collisions strongly distort the Maxwell-Boltzmann velocity distribution function, modifying not only the macroscopic chemical rate law but the kinetic-energy-transfer processes as well. This translational nonequilibrium ultimately introduces significant departures from the NS description in the kinetic energy spectra at scales orders of magnitude larger than both the molecular mean free path and the Kolmogorov length scale. These departures prove substantial enough to meaningfully alter integrated quantities, including the overall turbulence kinetic energy itself.

  View details for DOI 10.1073/pnas.2508608122

  View details for PubMedID 41037633

• Turbulence-chemistry interaction in a non-equilibrium hypersonic boundary layer JOURNAL OF FLUID MECHANICS Williams, C., Di Renzo, M., Moin, P. 2025; 1017

  View details for DOI 10.1017/jfm.2025.10479

  View details for Web of Science ID 001553022100001

• Review of shock-turbulence interaction with a focus on hypersonic flow PHYSICS OF FLUIDS Cuadra, A., Di Renzo, M., Hoste, J. E., Williams, C. T., Vera, M., Huete, C. 2025; 37 (4)

  View details for DOI 10.1063/5.0255816

  View details for Web of Science ID 001459669500022

• Navier-Stokes characteristic boundary conditions for high-enthalpy compressible flows in thermochemical non-equilibrium JOURNAL OF COMPUTATIONAL PHYSICS Williams, C., Di Renzo, M., Urzay, J., Moin, P. 2024; 509

  View details for DOI 10.1016/j.jcp.2024.113040

  View details for Web of Science ID 001235560400001

• Angular momentum and moment of total enthalpy integral equations for high-speed boundary layers PHYSICAL REVIEW FLUIDS Kianfar, A., Di Renzo, M., Williams, C., Elnahhas, A., Johnson, P. L. 2023; 8 (5)

  View details for DOI 10.1103/PhysRevFluids.8.054603

  View details for Web of Science ID 000989244100002