Three-dimensional Laminar Boundary-layer Analysis of Upwash Patterns and Entrained Vortex Formation on Sharp Cones at Angle of Attack

Three-dimensional Laminar Boundary-layer Analysis of Upwash Patterns and Entrained Vortex Formation on Sharp Cones at Angle of Attack
Author: John C. Adams (Jr.)
Publisher:
Total Pages: 124
Release: 1971
Genre: Aerodynamics, Hypersonic
ISBN:

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Application of three-dimensional inviscid and viscous (laminar boundary layer) analyses for cold wall hypersonic flows over sharp cones at incidence is presented relative to experimental data, showing surface upwash angles and entrained vortex formation leading to crossflow-induced boundary-layer transition. Three-dimensional neutral inviscid stability theory for stationary disturbances is used to calculate the angular orientation of the entrained vortices in the boundary layer while a maximum crossflow Reynolds number concept is applied for correlation of the onset to vortex formation due to crossflow instability.

Boundary-layer Transition on Cones Near Mach One in an Aeroballistic Range

Boundary-layer Transition on Cones Near Mach One in an Aeroballistic Range
Author: J. Leith Potter
Publisher:
Total Pages: 36
Release: 1975
Genre: Boundary layer
ISBN:

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The feasibility of determining Reynolds numbers of boundary layer transition on sharp, 10-deg, semiangle cones at slightly supersonic free-stream Mach numbers, 1.04 = or

NASA Technical Note

NASA Technical Note
Author:
Publisher:
Total Pages: 434
Release: 1972
Genre:
ISBN:

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The Effect of Pressure Gradients on Transition Zone Length in Hypersonic Boundary Layers

The Effect of Pressure Gradients on Transition Zone Length in Hypersonic Boundary Layers
Author: Roger L. Kimmel
Publisher:
Total Pages: 46
Release: 1993
Genre: Aerodynamics, Hypersonic
ISBN:

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Boundary layer transition was measured in zero, favorable, and adverse pressure gradients at Mach 8 using heat transfer. Models consisted of 7 degrees half angle forecones 0.4826 m long, followed by flared or ogive aft bodies 0.5334 m long. The flares and ogives produced constant pressure gradients. For the cases examined, favorable pressure gradients delay transition and adverse pressure gradients promote transition, but transition zone lengths are shorter in favorable pressure gradient. Results of the effect of adverse pressure gradient on transition zone lengths were inconclusive.

Hypersonic Laminar Boundary Layer Transition. Part 1. Nosetip Bluntness Effects on Cone Frustum Transition. Part 2. Mach 6 Experiments of Transition on a Cone at Angle of Attack

Hypersonic Laminar Boundary Layer Transition. Part 1. Nosetip Bluntness Effects on Cone Frustum Transition. Part 2. Mach 6 Experiments of Transition on a Cone at Angle of Attack
Author:
Publisher:
Total Pages: 108
Release: 1986
Genre:
ISBN:

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The effects of nosetip bluntness on cone frustrum boundary layer transition were investigated by conducting hypersonic wind tunnel experiments. Frustrum transition Reynolds numbers were found to have large variations within the entropy layer swallowing region. Investigation results indicated that several nosetip blunting effects were competing for the dominant role in the frustrum transition process and it was speculated that the large variations in transition Reynolds number were associated with the shifting of dominant roles. Based upon these studies, dominant nosetip bluntness effects are tentatively identified with three regions of the entropy layer. Transition movement and patterns on the frustrum of a cone at small angles of attack were investigated at a Mach number of 5.9, using an 8-deg half angle cone with both sharp and blunt nosetips. Small angles of attack produced large asymmetries in the frustrum transition pattern for both sharp and blunt tipped configurations. For the configurations with nosetip bluntness most of the frustrum transition asymmetry occurred between meridian angles of 60 and 120 deg. Data obtained with simulated laminar ablated nosetips were generally representative of what would be expected with a larger spherically blunt nosetip. Keywords: Boundary layer transition; Angle of attack.