EUNHA: a new cosmological hydro simulation code
  We have developed a parallel cosmological hydrodynamic simulation code
designed for the study of formation and evolution of cosmological structures.
The gravitational force is calculated using the TreePM method and the
hydrodynamics is implemented based on the smoothed particle hydrodynamics. The
initial displacement and velocity of simulation particles are calculated
according to second-order linear perturbation theory using the power spectra of
dark matter and baryonic matter. The initial background temperature is given by
Recfast and the temperature uctuations at the initial particle position are
determined by the adiabatic model. We use a time-limiter scheme over the
individual time steps to capture shock-fronts and to ease the time-step tension
between the shock and preshock particles. We also include the astrophysical gas
processes of radiative heating/cooling, star formation, metal enrichment, and
supernova feedback. We have tested the code in several standard cases such as
one-dimensional Riemann problems, Kelvin-Helmholtz, and Sedov blast wave
instability. Star formation on the galactic disk is investigated to check
whether the Schmidt-Kennicutt relation is properly recovered. We also study
global star formation histories at different simulation resolutions and compare
them with observations.
