  In this paper, the relation between skin friction and heat transfer along
windward sides of blunt-nosed bodies in hypersonic flows is investigated. The
self-similar boundary layer analysis is accepted to figure out the distribution
of the ratio of skin friction to heat transfer coefficients along the wall. It
is theoretically obtained that the ratio depends linearly on the local slope
angle of the wall surface, and an explicit analogy expression is presented for
circular cylinders, although the linear distribution is also found for other
nose shapes and even in gas flows with chemical reactions. Furthermore, based
on the theoretical modelling of the second order shear and heat transfer terms
in Burnett equations, a modified analogy is derived in the near continuum
regime by considering the rarefied gas effects. And a bridge function is also
constructed to describe the nonlinear analogy in the transition flow regime. At
last, the direct simulation Monte Carlo method is used to validate the
theoretical results. The general analogy, beyond the classical Reynolds
analogy, is applicable to both flat plates and blunt-nosed bodies, in either
continuous or rarefied hypersonic flows.
