Complex sentence: They correspond to the Navier-Stokes equations with zero viscosity and heat conduction terms, although they are usually written in the form shown below to emphasize that they directly represent conservation of mass, momentum, and energy.
Split into simpler sentences: They correspond to the Navier-Stokes equations with zero viscosity and heat conduction terms. They are usually written in the conservation form shown below to emphasize that they directly represent conservation of mass, momentum, and energy.