Comparison between the global flow stability of isothermal and adiabatic gaps in a boundary layer

Resumo

The global stability of a flow provides great insight to its behavior in the real world. Small imperfec-
tions in flat surfaces may accelerate the transition to turbulence, which has a great impact on the flow behavior

downstream as well as the overall lift and drag caused by such flow. The literature contains several simulations of

the flow over open cavities – of which gaps are a subset – however, there is no standard treatment for wall tempera-
ture, which is usually either isothermal or adiabatic, whereas the real-world condition is somewhere between both

scenarios. We wish to compare the global stability of both cases to measure the impact the wall temperature mod-
eling has over the overall flow. To achieve this, we will use and in-house developed open-source Direct Numerical

Simulation (DNS) code, coupled with its global stability routine. The simulation is subsonic yet compressible and
the parameters are chosen so that the flow is close to a critical stability condition, so that any differences between
both temperature treatments are maximized. Different temperature boundary conditions to cause the base flow to
settle at different temperatures, which in turn affects the flow density as well as the local Mach number. Our goal is
to better understand the role of surface temperature on flow stability so that we can better compare our simulations,
as well as those found in the literature, to experimental results as well as to real-world scenarios.