Calculation of nonequilibrium radiation from a blunt body shock layer

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.

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Spectroscopic emission measurements within the blunt-body shock layer in an arc-jet flow

10.2514/6.1997-990 ◽

1997 ◽

Author(s):

Chung Park ◽

Tahir Gokcen ◽

Mark Newfield ◽

Douglas Fletcher ◽

Surendra Sharma ◽

...

Keyword(s):

Shock Layer ◽

Blunt Body ◽

Jet Flow

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Measured nonequilibrium temperatures in a blunt body shock layer in arc jet nitrogen flow

10.2514/6.1997-2522 ◽

1997 ◽

Cited By ~ 1

Author(s):

Harvel Blackwell ◽

Carl Scott ◽

Sivaram Arepalli ◽

Harvel Blackwell ◽

Carl Scott ◽

...

Keyword(s):

Shock Layer ◽

Blunt Body ◽

Nitrogen Flow

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Viscous, Radiating Shock Layer about a Blunt Body

AIAA Journal ◽

10.2514/3.55179 ◽

1965 ◽

Vol 3 (9) ◽

pp. 1614-1622 ◽

Cited By ~ 22

Author(s):

H. HOSHIZAKI ◽

K. H. WILSON

Keyword(s):

Shock Layer ◽

Blunt Body

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Measurements of emission spectra from a shock layer of a blunt body in arc-heated gas

10.2514/6.2001-1760 ◽

2001 ◽

Cited By ~ 1

Author(s):

M. Hirakawa ◽

K. Abe ◽

M. Nishida ◽

K. Takeishi ◽

Katsuhiro Itoh

Keyword(s):

Shock Layer ◽

Blunt Body ◽

Emission Spectra

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Spectroscopic Emission Measurements Within the Blunt-Body Shock Layer in an Arcjet Flow

Journal of Thermophysics and Heat Transfer ◽

10.2514/2.6344 ◽

1998 ◽

Vol 12 (2) ◽

pp. 190-197 ◽

Cited By ~ 30

Author(s):

Chung S. Park ◽

Mark E. Newfield ◽

Douglas G. Fletcher ◽

Tahir Gokcen ◽

Surendra P. Sharma

Keyword(s):

Shock Layer ◽

Blunt Body

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Nonadiabatic Flow Around Blunt Bodies at Hyperbolic Speeds

Journal of Applied Mechanics ◽

10.1115/1.3408528 ◽

1970 ◽

Vol 37 (2) ◽

pp. 461-466

Author(s):

H. S. Bluston

Keyword(s):

Shock Layer ◽

Blunt Body ◽

Energy Equation ◽

Numerical Results ◽

Temperature Profiles ◽

Differential Approximation ◽

Blunt Bodies ◽

Method Of Integral Relations ◽

Nonadiabatic Effects ◽

Integral Relations

This investigation applies Belotserkovskii’s method of integral relations to the nonadiabatic, self-absorbing radiative flow of a gray gas about a sharp-cornered blunt body. The radiative quantities are represented by means of the “differential approximation.” Nonadiabatic effects are included both in the energy equation and in the shock layer temperature profiles. Numerical results are presented for flow about an Apollo-type capsule reentering the Earth’s atmosphere at an altitude of 190,000 ft and a velocity of 48,000 fps.

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