Experimental investigation on spiked body in hypersonic flow

2008 ◽  
Vol 112 (1136) ◽  
pp. 593-598 ◽  
Author(s):  
R. Kalimuthu ◽  
R. C. Mehta ◽  
E. Rathakrishnan
Keyword(s):  
Drag Reduction ◽  
Hypersonic Flow ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Angle Of Attack ◽  
Leading Edge ◽  
Geometrical Parameters ◽  
Potential Candidate ◽  
Hypersonic Wind Tunnel ◽  
High Speed Vehicle

Abstract A spike attached to a hemispherical body drastically changes its flowfield and influences aerodynamic drag in a hypersonic flow. It is, therefore, a potential candidate for drag reduction of a future high-speed vehicle. The effect of the spike length, shape, spike nose configuration and angle-of-attack on the reduction of the drag is experimentally studied with use of hypersonic wind-tunnel at Mach 6. The effects of geometrical parameters of the spike and angle-of-attack on the aerodynamic coefficient are analysed using schlieren picture and measuring aerodynamic forces. These experiments show that the aerodisk is superior to the aerospike. The aerodisk of appropriate length, diameter and nose configuration may have the capability for the drag reduction. The inclusion of an aero disk at the leading edge of the spike has an advantage for the drag reduction mechanism if it is at an angle-of-attack, however consideration to be given for increased moment resulting from the spike is required.

Numerical simulation of the flow field over conical, disc and flat spiked body at Mach 6

2010 ◽  
Vol 114 (1154) ◽  
pp. 225-236 ◽  
Author(s):  
R. C. Mehta
Keyword(s):  
Flow Field ◽  
Drag Reduction ◽  
High Speed ◽  
Blunt Body ◽  
Stokes Equations ◽  
Aerodynamic Drag ◽  
Dynamic Pressure ◽  
Recirculation Region ◽  
Potential Candidate ◽  
Wave Separation

Abstract A forward facing spike attached to a hemispherical body significantly changes its flow field and influences aerodynamic drag and wall heat flux in a high speed flow. The dynamic pressure in the recirculation area is highly reduced and this leads to the decrease in the aerodynamic drag and heat load on the surface. Consequently, the geometry, that is, the length and shape of the spike, has to be simulated in order to obtain a large conical recirculation region in front of the blunt body to get beneficial drag reduction. It is, therefore, a potential candidate for aerodynamic drag reduction for a future high speed vehicle. Axisymmetric compressible laminar Navier-Stokes equations are solved using a finite volume discretisation in conjunction with a multistage Runge-Kutta time stepping scheme. The effect of the spike length and shape, and the spike nose configuration on the reduction of drag is numerically evaluated at Mach 6 at a zero angle-of-attack. The computed density contours agree well with the schlieren images. Additional modification to the tip of the spike to get different types of flow field such as the formation of a shock wave, separation area and reattachment point are examined. The spike geometries include the conical spike, the flat-disk spike and the hemispherical disk spike of different length to diameter ratios attached to the blunt body.

Investigation of aerodynamic coefficients at Mach 6 over conical, hemispherical and flat-face spiked body

2017 ◽  
Vol 121 (1245) ◽  
pp. 1711-1732 ◽  
Author(s):  
R. Kalimuthu ◽  
R. C. Mehta ◽  
E. Rathakrishnan
Keyword(s):  
Flow Field ◽  
Blunt Body ◽  
Angle Of Attack ◽  
Separated Flow ◽  
Leading Edge ◽  
Aerodynamic Characteristics ◽  
Geometrical Parameters ◽  
Aerodynamic Coefficients ◽  
Aerodynamic Forces ◽  
Flow Field Characteristics

ABSTRACTA forward spike attached to a blunt body significantly alters its flow field characteristics and influences aerodynamic characteristics at hypersonic flow due to formation of separated flow and re-circulation region around the spiked body. An experimental investigation was performed to measure aerodynamic forces for spikes blunt bodies with a conical, hemispherical and flat-face spike at Mach 6 and at an angle-of-attack range from 0° to 8° and length-to-diameterL/Dratio of spike varies from 0.5 to 2.0, whereLis the length of the spike andDis diameter of blunt body. The shape of the leading edge of the spiked blunt body reveals different types of flow field features in the formation of a shock wave, shear layer, flow separation, re-circulation region and re-attachment shock. They are analysed with the help of schlieren pictures. The shock distance ahead of the hemisphere and the flat-face spike is compared with the analytical solution and is showing satisfactory agreement with the schlieren pictures. The influence of geometrical parameters of the spike, the shape of the spike tip and angle-of-attack on the aerodynamic coefficients are investigated by measuring aerodynamic forces in a hypersonic wind tunnel. It is found that a maximum reduction of drag of about 77% was found for hemisphere spike ofL/D= 2.0 at zero angle-of-attack. Consideration for compensation of increased pitching moment is required to stabilise the aerodynamic forces.

Aerodynamic drag reduction in winter sports: The quest for “free speed”

2020 ◽  
pp. 175433712092109
Author(s):  
Len Brownlie
Keyword(s):  
Wind Tunnel ◽  
Drag Reduction ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Ice Hockey ◽  
Future Research ◽  
Alpine Skiing ◽  
Winter Sports ◽  
Speed Skating ◽  
Cross Country

The Winter Olympics are a highly competitive sporting environment where subtle improvements in performance can impact the finishing order in many events. Aerodynamic drag is known to be a significant resistive force to human movement in high-speed sports, such as alpine skiing, speed skating and bobsleigh. Aerodynamic drag also represents an important determinant of performance in sports such as ice hockey, snowboard cross and cross-country skiing. From 2000 to 2018, a series of wind tunnel–based research projects were conducted to provide aerodynamically optimized apparel, equipment and wind tunnel simulation training to elite Canadian and American winter sports athletes involved in bobsleigh, skeleton, luge, ice hockey, speed skating, cross-country, alpine and para-alpine skiing, biathlon, ski-cross and snowboard cross. This article reviews the role of aerodynamic drag in winter sports, considers fundamental principles of air flow around bluff bodies and methods of drag reduction in ice and snow sports, while providing experimental results from an extensive database of wind tunnel investigations. Deficits in the literature suggest productive areas for future research to improve athletic performance in these sports.

Aerodynamic drag reduction by heat addition into the shock layer for a large angle blunt cone in hypersonic flow

2008 ◽  
Vol 20 (8) ◽  
pp. 081703 ◽  
Author(s):  
Vinayak Kulkarni ◽  
G. M. Hegde ◽  
G. Jagadeesh ◽  
E. Arunan ◽  
K. P. J. Reddy
Keyword(s):  
Drag Reduction ◽  
Hypersonic Flow ◽  
Shock Layer ◽  
Aerodynamic Drag ◽  
Large Angle ◽  
Blunt Cone ◽  
Heat Addition ◽  
Aerodynamic Drag Reduction

Lift Force of Delta Wings

1990 ◽  
Vol 43 (9) ◽  
pp. 209-221 ◽  
Author(s):  
Mario Lee ◽  
Chih-Ming Ho
Keyword(s):  
Lift Force ◽  
Delta Wing ◽  
Angle Of Attack ◽  
Leading Edge ◽  
Surface Flux ◽  
Experimental Results ◽  
Geometrical Parameters ◽  
Two Dimensional ◽  
Delta Wings ◽  
Vorticity Balance

On a delta wing, the separation vorticies can be stationary due to the balance of the vorticity surface flux and the axial convection along the swept leading edge. These stationary vortices keep the wing from losing lift. A highly swept delta wing reaches the maximum lift at an angle of attack of about 40°, which is more than twice as high as that of a two-dimensional airfoil. In this paper, the experimental results of lift forces for delta wings are reviewed from the perspective of fundamental vorticity balance. The effects of different operational and geometrical parameters on the performance of delta wings are surveyed.

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