Reduction of wave drag on parameterized blunt bodies using spikes with varied tip geometries

摘要

Aeospike based wave drag reduction is investigated using two-equation turbulence model applied to Faver averaged Navier Stokes solver. Three different blunt bodies are considered in a low supersonic stream of Mach number 2. The considered blunt bodies differ in their degree of bluntness defined in terms of half cone angle, area of flattened front side and radius of bluntness. The zero angle of attack flowfield around these three bodies are computationally analyzed with and without the presence of aft spikes to evaluate the wave drag resulting from the formation of front shock structure. The influence of spike configuration on the wave drag is also investigated. The various considered spike tip geometries include aero-disk, sharp and blunt with the length of all the spikes being equal to the base diameter of the blunt bodies (L/D = 1). It has been found that the 3221 blunt body when coupled with a blunt tipped spike yielded the lowest drag coefficient of 0.3, despite the 3221 having the highest standalone drag coefficient of 0.86, among the blunt bodies when simulated individually without spikes. The physics behind the wave drag reduction associated with each combination of blunt body and spike configuration is presented with clarity. This study portrays the importance of taking bluntness factor, semicone angle, fineness ratio and blunt body shape factor into consideration while proposing the generalized optimum spike configuration for minimum drag attainment.