Polytropic flow
= Polytropic flow
{title2=$p=K\rho^\gamma$}
A polytropic flow uses a <polytropic equation of state>. When $K$ and the <adiabatic exponent> are constant, a smooth streamline has <specific enthalpy> $h=\gamma K\rho^{\gamma-1}/(\gamma-1)$ and <adiabatic sound speed> $c_s^2=\gamma K\rho^{\gamma-1}$. Spatially varying entropy can make $K$ depend on streamline; the constant-$K$ spherical wind is a special case.