In this paper, the relation between skin friction and heat transfer alongwindward sides of blunt-nosed bodies in hypersonic flows is investigated. Theself-similar boundary layer analysis is accepted to figure out the distributionof the ratio of skin friction to heat transfer coefficients along the wall. Itis theoretically obtained that the ratio depends linearly on the local slopeangle of the wall surface, and an explicit analogy expression is presented forcircular cylinders, although the linear distribution is also found for othernose shapes and even in gas flows with chemical reactions. Furthermore, basedon the theoretical modelling of the second order shear and heat transfer termsin Burnett equations, a modified analogy is derived in the near continuumregime by considering the rarefied gas effects. And a bridge function is alsoconstructed to describe the nonlinear analogy in the transition flow regime. Atlast, the direct simulation Monte Carlo method is used to validate thetheoretical results. The general analogy, beyond the classical Reynoldsanalogy, is applicable to both flat plates and blunt-nosed bodies, in eithercontinuous or rarefied hypersonic flows.
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