Main Article Content
Abstract
Aerodynamic force and moment measurements were carried out on models of a typical re-entry body, featuring a blunt nose, conical body and flare, to assess the effect of flare angle on the overall aerodynamic characteristics. In one of the configurations, the junction between the cone and the flare was vented out to the base of the model to assess the effect of ventilation on the aerodynamic characteristics. It was expected that the stability characteristics would improve, by virtue of improved contribution from the flare to the normal force of the configuration. However, measurements did not show the expected trends. Instead, there was a remarkable reduction in the axial force with ventilation, by as much as 25% all across the Mach number and angle of attack range. Base pressure measurements indicated that in the low Mach number range pressure rise occured. However, in the high transonic Mach number range, even though the force measurements showed drag reduction, there was no significant rise in base pressure. Ventilation showed delay in transonic drag rise. It is therefore suggested that the overall pressure field is modified by ventilation, which results in drag reduction of the configuration.
Keywords
Article Details
References
- Suryanarayana, G.K., Henning Pauer and Meier, G.E.A., "Bluff-body Drag Reduction by Passive Ventilation", Experiments in Fluids, Vol.16, No. 2, pp. 73-81, 1993.
- Suryanarayana, G.K. and Meier, G.E.A., "Effect of Ventilation on the Flowfield Around a Sphere", Experiments in Fluids, Vol.19, No.2, pp.78-88, 1995.
- Suryanarayana, G.K. and Prabhu, A., "Effect of Natural Ventilation on the Boundary Layer Separation and Near-wake Vortex Shedding Characteristics of a Sphere", Experiments in Fluids, Vol.29, No.6, pp. 582-591, 2000.
- Suryanarayana, G.K., "On the Reduction of Drag of a Sphere by Natural Ventilation, Dissertation", Department of Aerospace Engineering, Indian Institute of Science, Bangalore, India, 1995.
- Suryanarayana, G.K., "Aerodynamic Drag Reduction of Bluff Bodies: Application of Natural Ventilation", Lambert Academic Publications, Germany, ISBN 978-3-8383-1103-6, 2009.
- Taneda, S., "Visual Observations of the Flow Past a Sphere at Reynolds Numbers Between 104 and 106 ". Journal of Fluid Mechanics, Vol. 85, Part-1, pp.187192, 1978.
- Lu, M., Grosche, F.R. and Meier, G.E.A., "Drag Reduction of a Sphere at Supercritical Reynolds Numbers Using Passive Ventilation", IUTAMSymposium on Mechanics of Passive and Active Flow Control, 1998.
- Sejeong Jeon., Jin Choi., Woo-Pyung Jeon., Heachon Choi and Jinil Park., "Active Control of Flow Over a Sphere for Drag Reduction at Subcritical Reynolds Number", Journal of Fluid Mechanics, Vol.517, pp.113-129, 2004.
- Grosche, F.R. and Meier, G.E.A., "Research at DLR Go.. ttingen on Bluff Body Aerodynamics, Drag Reduction by Wake Ventilation and Active Flow Control", Journal of Wind Engineering and Industrial
- Aerodynamics, Vol.89, Issues 14-15, pp.1201-1218, 2001.
- Falchi., Provenzano,G., Pietrogiacomi, D. and Romano, G.P., "Experiments and Numerical Investigation of Flow Control on Bluff Bodies by Passive Ventilation", Experiments in Fluids, Vol.41, No.1,
- pp.21-33, 2006.
- Igarashi., "Flow Characteristics Around a Circular Cylinder with a Slot Bull", JSME 21 154, pp.656-
- , 1978.
- Suryanarayana, G.K., Meir, G.E.A. and Henning Pauer., "Vented Circular Cylinder as a Vortex Generator", Journal of Visualization, Vol.8, No.3, 2005.
- Achenbach, E., "The Effects of Surface Roughness and Tunnel Blockage on Flow Past Spheres". Journal of Fluid Mechanics, Vol.65:1, pp.113-125, 1974.
References
Suryanarayana, G.K., Henning Pauer and Meier, G.E.A., "Bluff-body Drag Reduction by Passive Ventilation", Experiments in Fluids, Vol.16, No. 2, pp. 73-81, 1993.
Suryanarayana, G.K. and Meier, G.E.A., "Effect of Ventilation on the Flowfield Around a Sphere", Experiments in Fluids, Vol.19, No.2, pp.78-88, 1995.
Suryanarayana, G.K. and Prabhu, A., "Effect of Natural Ventilation on the Boundary Layer Separation and Near-wake Vortex Shedding Characteristics of a Sphere", Experiments in Fluids, Vol.29, No.6, pp. 582-591, 2000.
Suryanarayana, G.K., "On the Reduction of Drag of a Sphere by Natural Ventilation, Dissertation", Department of Aerospace Engineering, Indian Institute of Science, Bangalore, India, 1995.
Suryanarayana, G.K., "Aerodynamic Drag Reduction of Bluff Bodies: Application of Natural Ventilation", Lambert Academic Publications, Germany, ISBN 978-3-8383-1103-6, 2009.
Taneda, S., "Visual Observations of the Flow Past a Sphere at Reynolds Numbers Between 104 and 106 ". Journal of Fluid Mechanics, Vol. 85, Part-1, pp.187192, 1978.
Lu, M., Grosche, F.R. and Meier, G.E.A., "Drag Reduction of a Sphere at Supercritical Reynolds Numbers Using Passive Ventilation", IUTAMSymposium on Mechanics of Passive and Active Flow Control, 1998.
Sejeong Jeon., Jin Choi., Woo-Pyung Jeon., Heachon Choi and Jinil Park., "Active Control of Flow Over a Sphere for Drag Reduction at Subcritical Reynolds Number", Journal of Fluid Mechanics, Vol.517, pp.113-129, 2004.
Grosche, F.R. and Meier, G.E.A., "Research at DLR Go.. ttingen on Bluff Body Aerodynamics, Drag Reduction by Wake Ventilation and Active Flow Control", Journal of Wind Engineering and Industrial
Aerodynamics, Vol.89, Issues 14-15, pp.1201-1218, 2001.
Falchi., Provenzano,G., Pietrogiacomi, D. and Romano, G.P., "Experiments and Numerical Investigation of Flow Control on Bluff Bodies by Passive Ventilation", Experiments in Fluids, Vol.41, No.1,
pp.21-33, 2006.
Igarashi., "Flow Characteristics Around a Circular Cylinder with a Slot Bull", JSME 21 154, pp.656-
, 1978.
Suryanarayana, G.K., Meir, G.E.A. and Henning Pauer., "Vented Circular Cylinder as a Vortex Generator", Journal of Visualization, Vol.8, No.3, 2005.
Achenbach, E., "The Effects of Surface Roughness and Tunnel Blockage on Flow Past Spheres". Journal of Fluid Mechanics, Vol.65:1, pp.113-125, 1974.