<div class="csl-bib-body">
<div class="csl-entry">Cogo, M., Baù, U., Chinappi, M., Bernardini, M., & Picano, F. (2023). Assessment of heat transfer and Mach number effects on high-speed turbulent boundary layers. <i>Journal of Fluid Mechanics</i>, <i>974</i>, Article A10. https://doi.org/10.1017/jfm.2023.791</div>
</div>
-
dc.identifier.issn
0022-1120
-
dc.identifier.uri
http://hdl.handle.net/20.500.12708/191212
-
dc.description.abstract
High-speed vehicles experience a highly challenging environment in which the freestream Mach number and surface temperature greatly influence aerodynamic drag and heat transfer. The interplay of these two parameters strongly affects the near-wall dynamics of high-speed turbulent boundary layers (TBLs) in a non-trivial way, breaking similarity arguments on velocity and temperature fields, typically derived for adiabatic cases. We present direct numerical simulations of flat-plate zero-pressure-gradient TBLs spanning three freestream Mach numbers and four wall temperature conditions (from adiabatic to very cold walls), emphasising the choice of the wall-cooling parameter to recover a similar flow organisation at different Mach numbers. We link qualitative observations on flow patterns to first- and second-order statistics to explain the decoupling of temperature-velocity fluctuations that occurs at reduced wall temperatures and high Mach numbers. For these cases, we discuss the formation of a secondary peak of thermal production in the viscous sublayer, which is in contrast with the monotonic behaviour of adiabatic profiles. We propose different physical mechanisms induced by wall-cooling and compressibility that result in apparently similar flow features, such as a higher peak in the streamwise velocity turbulence intensity, and distinct features, such as the separation of turbulent scales.
-
dc.language.iso
en
-
dc.publisher
CAMBRIDGE UNIV PRESS
-
dc.relation.ispartof
Journal of Fluid Mechanics
-
dc.subject
compressible boundary layers
-
dc.subject
turbulent boundary layers
-
dc.title
Assessment of heat transfer and Mach number effects on high-speed turbulent boundary layers