High Relative Velocity Research Articles

On high speed wind tunnels

The experiments on efflux of gases from orifices show that important changes occur in the properties of a gas accelerated to high velocity, apparently due to changes in the distribution of molecular energies. These changes indicate that conditions of the air flow around a body depend not only on the relative velocity, but on the absolute velocity of the air as well. Therefore, the results of the model tests obtained in wind tunnels at the velocity approaching that of sound do not correspond to the practical case of a body moving through still air. In particular, the occurrence of the compression shock appears to represent the characteristic of the high speed air stream, rather than that of the high relative velocity of the model and the air.