The Experimental Study of the Effect of Aerospike on Reducing the Drag of Three Types of Blunt Noses at Mach Number of 6.4

The main challenges facing the designers of hypersonic flying objects are the significant amount of pressure drag and aerodynamic heating. However, blunt noses are preferred for better heat distribution, but they produce a lot of drag force. Spikes and aero disks are effective tools for reducing drag and heating. In this study, the effects of aerospike geometry on the drag reduction of three types of hemispherical, Trident and HB1 noses, in a hypersonic wind tunnel have been evaluated. Experiments were performed on blunt noses in the two conditions of with and without aerospike at Mach number of 6.4 by measuring the drag force and observing the shock waves using the Schlieren technique. For this study, two hemispherical aerospikes with length to diameter ratios of 1 and 2 were considered. The results show that in all three noses, the aerospike converts a strong bow shock into a weak shock, and followed by a rotational zone or dead air zone, reduces the pressure in front of the nose and hence, leads to less drag exertion. The main cause of drag reduction is the aerospike nose and the optimal spike length to diameter ratio is with the blunt nose geometry. The highest drag reduction of 74.8% is observed for an aero disk with the length to diameter ratio of 2 in the hemispherical blunt nose.