Cone Forebody Research Articles

Effect of the surface roughness of blunt cone forebody on the position of laminar-turbulent transition

In the present paper, data on the effect of the surface roughness of blunt cone forebody on the position of laminar-turbulent transition are reported. The study was carried out under freestream Mach 5.95. It was found that the roughness position plays a substantial role in the transition process. Critical Reynolds numbers at which the laminar-turbulent transition occurs on the nose-tip of the model were identified. For the first time, hysteresis in transition position was observed.

Experimental study on side force alleviation of conical forebody with a fluttering flag

Slender bodies of revolution placed at high angles of attack will produce a steady asymmetric vortex pair. This behavior is determined by the spatial instability of the flow. The asymmetric vortex pair is very sensitive to small disturbances near the tip. This paper presents a simple side force alleviation method without a power unit for slender bodies at high angles of attack. The method uses the self-excited oscillation (flutter) of a small cantilever flag as the excitation source on the cone tip. An experimental study is performed to investigate the characteristics of the asymmetric side forces of a 20° cone-cylinder slender body with and without a small flutter flag. Pressure distribution at eight cross sections of the cone forebody is measured at different free-stream velocities and different angles of attack. The process demonstrates that the excitation provided by the fluttering flag can change the asymmetric bistable flow state to a well symmetric one at high angles of attack, and that the corresponding side force and yaw moment will significantly decrease. The flutter strength of the flag will be enhanced by increasing the free-stream velocity. The effectiveness of the side force alleviation method will also be increased.

Flow Control over a Circular-Cone-Cylinder by Unsteady Plasma Actuations

An experimental study of plasma duty-cycled actuation over slender forebodies is performed on a 20° circular-cone-cylinder model using a pair of Single Dielectric Barrier Discharge (SDBD) plasma actuators near the cone apex combined with a duty-cycle technique. The tests are carried out in a low-turbulence 3.0 m ×1.6 m low-speed wind tunnel at an angle of attack of 45°. The Reynolds number based on the cone base diameter is 50, 000. The frequency of the duty cycle is 10 Hz. The mechanisms of the unsteady excitations over various duty cycles of frequency 10 Hz are studied using ten Kulite pressure transducers mounted around a cross section of the cone forebody at angle of attack of 45°.The circumferential pressure distributions over a station on the cone forebody is measured by unsteady pressure tappings, Phase-locked averaged pressures are studied and compared with ensemble-averaged pressures.