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## Main Question or Discussion Point

Hi Physics Forums!

I would like to know how to model a thin, infinitely-long circular cylinder moving axially at hypersonic speeds. For something I would expect to be a base case in most hypersonics textbooks, it's surprisingly difficult to find a straight answer.

In particular what is the:

• heat over cylinder surface

• drag force on the cylinder

The closest thing I have been able to find so far is GK Batchelor's "The Skin Friction on Infinite Cylinders Moving Parallel to their Length" (1954) which gives a solution for subsonic speeds only. There, the drag force is:

8 • dynamicViscosity • ∫{ [ e

The closest thing I can think of to model this is that Rods from God idea about de-orbiting telephone poles to hit targets. Unfortunately I can't find much on their aerodynamics either (just religious stuff).

Many thanks!

-mLuby

I would like to know how to model a thin, infinitely-long circular cylinder moving axially at hypersonic speeds. For something I would expect to be a base case in most hypersonics textbooks, it's surprisingly difficult to find a straight answer.

In particular what is the:

• heat over cylinder surface

• drag force on the cylinder

The closest thing I have been able to find so far is GK Batchelor's "The Skin Friction on Infinite Cylinders Moving Parallel to their Length" (1954) which gives a solution for subsonic speeds only. There, the drag force is:

8 • dynamicViscosity • ∫{ [ e

^{(-k2)(kinematicViscosity)(timePeriod)}] / [ k•BesselJ(cylinderRadius•k)^{2}+ BesselY(cylinderRadius•k)^{2}] }dkThe closest thing I can think of to model this is that Rods from God idea about de-orbiting telephone poles to hit targets. Unfortunately I can't find much on their aerodynamics either (just religious stuff).

Many thanks!

-mLuby