  In stars and planets natural processes heat convective flows in the bulk of a
convective region rather than at hard boundaries. By characterizing how
convective dynamics are determined by the strength of an internal heating
source we can gain insight into the processes driving astrophysical convection.
Internally heated convection has been studied extensively in incompressible
fluids, but the effects of stratification and compressibility have not been
examined in detail. In this work, we study fully compressible convection driven
by a spatially uniform heating source in 2D and 3D Cartesian, hydrodynamic
simulations. We use a fixed temperature upper boundary condition which results
in a system that is internally heated in the bulk and cooled at the top. We
find that the flow speed, as measured by the Mach number, and turbulence, as
measured by the Reynolds number, can be independently controlled by separately
varying the characteristic temperature gradient from internal heating and the
diffusivities. 2D simulations at a fixed Mach number (flow speed) demonstrate
consistent power at low wavenumber as diffusivities are decreased. We observe
convection where the velocity distribution is skewed towards cold, fast
downflows, and that the flow speed is related to the length scale and entropy
gradient of the upper boundary where the downflows are driven. We additionally
find a heat transport scaling law which is consistent with prior incompressible
work.
