scholarly journals High pressure oblique shock interactions in NATO fragment impacts

2020 ◽  
Author(s):  
Kevin T. Miers ◽  
Nausheen M. Al-Shehab ◽  
Daniel J. Pudlak
Keyword(s):  
High Pressure ◽  
Oblique Shock ◽  
Shock Interactions

Glancing interactions between single and intersecting oblique shock waves and a turbulent boundary layer

1986 ◽  
Vol 170 ◽  
pp. 411-433 ◽  
Author(s):  
D. J. Mee ◽  
R. J. Stalker ◽  
J. L. Stollery
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Pressure Field ◽  
Superposition Principle ◽  
Three Dimensional ◽  
Oblique Shock ◽  
Shock Interactions ◽  
Expansion Waves ◽  
Shock Generator ◽  
Boundary Layer Interaction

The three-dimensional interactions of weak swept oblique shock and expansion waves and a turbulent boundary layer on a flat plate are investigated. Upstream influences in a single swept interaction are found to be consistent with a model of the flow involving shock/boundary-layer interaction characteristics. The model implies that there is more rapid thickening of the boundary layer close to the shock generator and this is seen to be consistent with surface streamline patterns. It is also found that a superposition principle, which is inherent in the triple-deck model of shock/boundary-layer interactions proposed by Lighthill, can be used to predict the pressure field and surface streamlines for the case of intersecting shock interactions and for the intersection of a shock with a weak expansion.

scholarly journals Experiments on Oblique Shock Interactions with Planar Mixing Regions

AIAA Journal ◽  
10.2514/2.26 ◽  
1997 ◽  
Vol 35 (11) ◽  
pp. 1774-1777 ◽  
Author(s):  
D. R. Buttsworth ◽  
R. G. Morgan ◽  
T. V. Jones
Keyword(s):  
Oblique Shock ◽  
Shock Interactions

A Comparison Between Numerical and Experimental High Reynolds Number Supersonic Jets Generated by Millimeter Scale Converging-Diverging Nozzles

2020 ◽  
Author(s):  
Joseph M. Conahan ◽  
Ozan C. Ozdemir ◽  
Mohammad E. Taslim ◽  
Sinan Muftu
Keyword(s):  
Surface Roughness ◽  
Shock Waves ◽  
Supersonic Jet ◽  
Jet Impingement ◽  
Internal Surface ◽  
Supersonic Jets ◽  
Oblique Shock ◽  
Shock Interactions ◽  
Schlieren Visualization ◽  
High Reynolds

Abstract In thermal spray applications, such as cold spray, an inert gas jet (typically helium or nitrogen) is used to accelerate micron scale particles to supersonic velocities. The complex gas dynamics of these supersonic jets are critical to understand via computational methods for the control of the spray. This work compares supersonic jet waveforms visualized by schlieren imaging with those predicted by computational fluid dynamics (CFD) simulations. A supersonic nitrogen jet is produced by a millimeter scale converging-diverging nozzle with inlet pressures as high as 50 bars. The jet Reynolds numbers based on the nozzle exit diameter and stagnation gas properties range between 60,000 to 325,000. A schlieren visualization setup has been built which shows the first spatial derivative of densities within the flow field. The strong density gradients across the oblique shock waves in the jets allow for clear photographs of the flow pattern of the jets using this schlieren visualization setup. Comparisons between the experiments and the CFD results act as a validation technique for the accuracy of the simulations in terms of the positions and orientations of the oblique shock waves. Through this study, the nozzle internal surface roughness is determined to be a critical parameter in millimeter scale nozzles for the development of the boundary layer. The CFD surface roughness parameters inside the nozzle are incremented until the geometry of the oblique shock waves matches the schlieren images. This work validates the simulation techniques which will be used for future jet simulations, in which shock wave locations and orientations are important, such as jet impingement on a flat plate and particle-shock interactions.

scholarly journals Experiments on oblique shock interactions with planar mixing regions

AIAA Journal ◽  
1997 ◽  
Vol 35 ◽  
pp. 1774-1777
Author(s):  
D. R. Buttsworth ◽  
R. G. Morgan ◽  
T. V. Jones
Keyword(s):  
Oblique Shock ◽  
Shock Interactions

RANS Modelling of Shock-Wave Boundary Layer Interaction in a Mixed Compression Axisymmetric Hypersonic Intake

2016 ◽  
Vol 846 ◽  
pp. 61-66
Author(s):  
Abhijeet Kumar ◽  
Ben Thornber
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Computational Study ◽  
Oblique Shock ◽  
Bow Shock ◽  
Shock Interactions ◽  
Layer Interaction ◽  
Wave Boundary Layer ◽  
Boundary Layer Interaction ◽  
Wave Boundary

This work focuses on developing a design methodology for a mixed compression axisymmetric hypersonic intake and numerically computing flow around the designed intake using RANS methods to study shock/shock and shock wave/boundary layer interaction. The focus of the computational study is on the effect of increasing the blunt radius of the cowl lip on the resulting shock/shock interaction between the oblique shock emanating from the cone compression apex and the bow shock on the cowl lip; as well the resulting reflected oblique shock boundary layer interaction from the cowl tip onto the cone compression surface. Three (3) radii are tested: 2mm, 16mm and 32mm at Mach 2 and the study is extended to a nominal 16mm condition at Mach 5. It is found that with increasing cowl-lip radius the magnitude of the shock-wave/boundary layer interaction increases significantly. Separation on the cone compression surface is observed at the 16mm and 32mm case at the Mach 2 position and in the 16mm case at the Mach 5 position. In addition in the 16mm and 32mm cases at the Mach 2 position, a Mach stem is observed. The shock/shock interactions, however, are found to be less dramatic. Type III and IV phenomena are observed, however, there is limited interference with the bow shock.

High-pressure freezing of cells in suspension for low-voltage scanning electron microscopy (LVSEM)

1991 ◽  
Vol 49 ◽  
pp. 64-65
Author(s):  
Marek Malecki ◽  
James Pawley ◽  
Hans Ris
Keyword(s):  
Electron Microscopy ◽  
High Pressure ◽  
Low Voltage ◽  
Culture Media ◽  
Cell Structure ◽  
Freeze Substitution ◽  
Ice Crystal ◽  
High Pressure Freezing ◽  
Cell Culture Media ◽  
Voltage Scanning

The ultrastructure of cells suspended in physiological fluids or cell culture media can only be studied if the living processes are stopped while the cells remain in suspension. Attachment of living cells to carrier surfaces to facilitate further processing for electron microscopy produces a rapid reorganization of cell structure eradicating most traces of the structures present when the cells were in suspension. The structure of cells in suspension can be immobilized by either chemical fixation or, much faster, by rapid freezing (cryo-immobilization). The fixation speed is particularly important in studies of cell surface reorganization over time. High pressure freezing provides conditions where specimens up to 500μm thick can be frozen in milliseconds without ice crystal damage. This volume is sufficient for cells to remain in suspension until frozen. However, special procedures are needed to assure that the unattached cells are not lost during subsequent processing for LVSEM or HVEM using freeze-substitution or freeze drying. We recently developed such a procedure.

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