Aerothermodynamics of a hypersonic projectile with a double-disk aerospike

Abstract

The use of aerospikes at the nose of a hypersonic vehicle can substantially reduce its drag; however, the associated heat flux at the reattachment point is very high for turbulent flows. In this paper, the aerothermodynamics of a generic projectile model represented by a hemisphere-cylinder, fitted axisymmetrically with an aerospike at the nose is investigated numerically with a commercially available Navier Stokes Solver. The base model is a hemisphere-cylinder with a diameter of 40mm and an overall length of 70mm. An aerospike protrudes axisymmetrically at the nose of the base model and has a hemispherical cap from which another aerospike protrudes which again has a hemispherical cap, thus forming a double-disk aerospike. Compressible, axisymmetric NavierStokes Equations are solved for turbulent hypersonic flow of thermally perfect air with free stream conditions of Mach No 6·2 at standard sea level atmospheric conditions. The results for the model with double-disk aerospikes are compared with those of hemisphere-cylinder without aerospike. The results suggest that the use of double-disk aerospike can favourably reduce the turbulent reattachment heat flux along with suitable drag reduction of the main body.

Drag reduction investigation for hypersonic lifting-body vehicles with aerospike and long penetration mode counterflowing jet

“…The effects of the spike length, shape, spike nose configuration and angle of attack on the reduction of the drag were experimentally studied by Kalimuthu et al [25], and they found that the aerodisk with L/D = 2.0 is most effective among the models tested. Yadav and Guven [26] proved numerically that double-disk aerospikes are superior to single disk aerospikes of same overall length and hemispherical cap size in reducing drag of the main body. To study the aerodynamic characteristic of spike at a certain angle of attack, Schülein [27] introduced the concept of "pivoting spike" in which the spike is maintained aligned with the freestream direction while the whole body is at incidence.…”

Effect of intermediate aerodisk mounted sharp tip spike on the drag reduction over a hemispherical body at Mach 2.0

“…Further, in order to reduce the amount of drag reduction for the spiked body configuration with a spike of length beyond the critical length (L/D=2.0), an intermediate aerodisk is mounted on the spike stem. The geometry of the intermediate aerodisk used in the present investigation is adopted with reference to the aerodisk used by Yadav et al [15][16]. The point of flow separation over the spike length for longest spike (L/D=2.0) has been considered as the location of mounting the intermediate aerodisk.…”

“…This reduces the level of the surface pressure and hence a reduction in drag coefficient in obtained. Recently, Yadav et al [15][16] using computational studies reported an even further increase in the amount of drag reduction at hypersonic flow by mounting a series of aerodisk along the spike stem in comparison to a single aerodisk mounted spiked body configuration. In addition to the spiked blunt bodies, numerous studies have also been conducted involving the investigation of the aerodynamic forces over more streamlined bodies (Cone and Ogive) without mounting any spike [17][18][19].…”

“…The flowfield obtained around the hemispherical body by mounting a sharp tip spike of critical spike length is compared with the one ob- tained by mounting a spike of length longer than the critical limit. Furthermore, an attempt is made to increase the percentage of drag reduction on a spike length beyond the critical limit by utilizing the information provided by Jones [4] and Yadav et al [15][16].…”

Spike Effects on Drag Reduction for Hypersonic Lifting Body

“…The flat faced disk has a larger structural strength than hemispheric disk because of its geometric shape at the cruise angle, ensuring its durability under heavy lateral loads, also reduces elastic deformation at hypersonic speeds. [7] showed that the drag of the vehicle nose is remarkably influenced by the disk shape, and [18] suggested that the use of double-disk aerospike can favourably reduce drag, considering from the aspect, SFF and DFF with appropriate disk shape and position, shown in Fig. 2(b) and (c), are added in the research to compare with the hemispheric disk in order to carry out the disk shape selection.…”