An experimental investigation of a two-layer inviscid shock cap due to blunt-body nose injection

1963 ◽  
Vol 15 (3) ◽  
pp. 442-448 ◽  
Author(s):  
Judson R. Baron ◽  
Edgar Alzner
Keyword(s):  
Experimental Investigation ◽  
Mach Number ◽  
Contact Surface ◽  
Blunt Body ◽  
The Body ◽  
Bow Shock ◽  
Mass Injection ◽  
Axisymmetric Channel ◽  
Injection Rates

Blunt-body solutions for suspersonic flow usually concern closed body surfaces. This paper reports on an experimental investigation of a two-layer shock cap and indicates the existence of a predictable contact surface separating the layers. The inner layer was generated by injecting air through a contoured axisymmetric channel on a blunt body so as to simulate a hemispherical contact surface in a Mach number 4.8 flow.Results show the existence of the contact surface and the influence of a range of mass-injection rates upon the displacement of the bow shock and contact surface from the body.

Aerodynamic and Numerical Study on the Influence of Spike Shapes at Mach 1.5

2014 ◽  
Vol 1046 ◽  
pp. 177-181
Author(s):  
Yong Hong Li ◽  
Xin Wu Tang ◽  
Wei Qun Zhou
Keyword(s):  
Hypersonic Flow ◽  
Body Surface ◽  
Blunt Body ◽  
Numerical Study ◽  
Aerodynamic Characteristics ◽  
The Body ◽  
Bow Shock ◽  
Aerodynamic Heating ◽  
Recirculation Flow ◽  
Flight Vehicles

Taking into account the issue of configuration or aerodynamic heating, most supersonic and hypersonic flight vehicles have to use the blunt-nosed body. However, in supersonic especially in hypersonic flow the strong bow shock ahead of the blunt nose introduces a rather high shock drag that affects the aerodynamic performance of the vehicles seriously. A spike mounted on a blunt body during its flight pushes the strong bow shock away from the body surface and forms recirculation flow with low pressure ahead of the body surface, and then decreases the drag. The drag reduction effects of spikes in high supersonic and hypersonic flow had been validated through experimental and numerical methods. In order to analyze the influence of the spike on aerodynamic characteristics at low supersonic (M=1.5) flow past blunt-nosed bodies, numerical studies were carried out which included the influence of the spike shape, the analysis of the fluid flow structures and the effect on the aerodynamic characteristics of a blunt body.

A numerical study on the single pulsed energy addition based unsteady wave drag reduction at varied hypersonic flow regimes

2020 ◽  
pp. 095441002097313
Author(s):  
Dathi SNV Rajasekhar Rao ◽  
Bibin John
Keyword(s):  
Steady State ◽  
Mach Number ◽  
Drag Reduction ◽  
Shock Layer ◽  
Blunt Body ◽  
Wave Drag ◽  
Flow Features ◽  
Energy Pulse ◽  
Energy Addition ◽  
Wave Drag Reduction

In this study, unsteady wave drag reduction in hypersonic flowfield using pulsed energy addition is numerically investigated. A single energy pulse is considered to analyze the time-averaged drag reduction/pulse. The blast wave creation, translation and its interaction with shock layer are studied. As the wave drag depends only on the inviscid aspects of the flowfield, Euler part of a well-established compressible flow Navier-Stokes solver USHAS (Unstructured Solver for Hypersonic Aerothermodynamics) is employed for the present study. To explore the feasibility of pulsed energy addition in reducing the wave drag at different flight conditions, flight Mach numbers of 5.75, 6.9 and 8.0 are chosen for the study. An [Formula: see text] apex angle blunt cone model is considered to be placed in such hypersonic streams, and steady-state drag and unsteady drag reductions are computed. The simulation results indicate that drag of the blunt-body can be reduced below the steady-state drag for a significant period of energy bubble-shock layer interaction, and the corresponding propulsive energy savings can be up to 9%. For energy pulse of magnitude 100mJ deposited to a spherical region of 2 mm radius, located 50 mm upstream of the blunt-body offered a maximum percentage of wave drag reduction in the case of Mach 8.0 flowfield. Two different flow features are found to be responsible for the drag reduction, one is the low-density core of the blast wave and the second one is the baroclinic vortex created due to the plasma energy bubble-shock layer interaction. For the same freestream stagnation conditions, these two flow features are noted to be very predominant in the case of high Mach number flow in comparison to Mach 5.75 and 6.9 cases. However, the ratio of energy saved to the energy consumed is noted as a maximum for the lower Mach number case.

scholarly journals Correction to: Experimental investigation of blunt cone model at hypersonic Mach number 7.25

2021 ◽  
Vol 43 (7) ◽  
Author(s):  
Saiprakash Mani ◽  
C. Senthilkumar ◽  
G. Kadam Sunil ◽  
Singh Prakash Rampratap ◽  
V. Shanmugam ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Mach Number ◽  
Blunt Cone ◽  
Cone Model

scholarly journals Experimental Investigation of Tandem Blade Cascades With Double-Circular ARC Profiles

1985 ◽  
Author(s):  
Wu Guochuan ◽  
Zhuang Biaonan ◽  
Guo Bingheng
Keyword(s):  
Experimental Investigation ◽  
Reynolds Number ◽  
Mach Number ◽  
Total Pressure ◽  
Incidence Angle ◽  
Axial Direction ◽  
Geometrical Parameters ◽  
Optimal Conditions ◽  
Turning Angle ◽  
Circular Arc

24 double circular are tandem blade cascades of three different chord-ratios were investigated under different displacements in peripheral and axial direction. The inlet Mach number was 0.3. The Reynolds number based on blade chord was 2.7×105. The characteristics of the tandem blade cascades, such as the dependence of turning angle and coefficient of total pressure loss on incidence angle were obtained. The ranges of main geometrical parameters under optimal conditions were recommended.

Maximizing Recall of Gruesome Images for Health Effects Advertising: An Experimental Investigation

2010 ◽  
Vol 16 (4) ◽  
pp. 112-121 ◽  
Author(s):  
Brennen W. Mills ◽  
Owen B. J. Carter ◽  
Robert J. Donovan
Keyword(s):  
Experimental Investigation ◽  
Body Part ◽  
The Body ◽  
Advertising Effectiveness ◽  
Body Parts ◽  
Online Study ◽  
Video Clips ◽  
Video Images ◽  
The Impact

The objective of this case study was to experimentally manipulate the impact on arousal and recall of two characteristics frequently occurring in gruesome depictions of body parts in smoking cessation advertisements: the presence or absence of an external physical insult to the body part depicted; whether or not the image contains a clear figure/ground demarcation. Three hundred participants (46% male, 54% female; mean age 27.3 years, SD = 11.4) participated in a two-stage online study wherein they viewed and responded to a series of gruesome 4-s video images. Seventy-two video clips were created to provide a sample of images across the two conditions: physical insult versus no insult and clear figure/ground demarcation versus merged or no clear figure/ground demarcation. In stage one, participants viewed a randomly ordered series of 36 video clips and rated how “confronting” they considered each to be. Seven days later (stage two), to test recall of each video image, participants viewed all 72 clips and were asked to identify those they had seen previously. Images containing a physical insult were consistently rated more confronting and were remembered more accurately than images with no physical insult. Images with a clear figure/ground demarcation were rated as no more confronting but were consistently recalled with greater accuracy than those with unclear figure/ground demarcation. Makers of gruesome health warning television advertisements should incorporate some form of physical insult and use a clear figure/ground demarcation to maximize image recall and subsequent potential advertising effectiveness.

Microinstabilities associated with a high Mach number, perpendicular bow shock

1984 ◽  
Vol 37 (1-2) ◽  
Author(s):  
C.S. Wu ◽  
D. Winske ◽  
Y.M. Zhou ◽  
S.T. Tsai ◽  
P. Rodriguez ◽  
...  
Keyword(s):  
Mach Number ◽  
Bow Shock ◽  
High Mach Number ◽  
High Mach
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