Supersonic Inlet Shaping for Dramatic Reductions in Drag and Sonic Boom Strength

Conners, Timothy R.; Howe, D.

doi:10.2514/6.2006-30

Cited by 33 publications

(13 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…They must reduce the Mach number from 1.7 over the wing to about 0.65 at the fan face, with high total pressure recovery, minimal distortion, and with minimal sonic boom. Conners and Howe at GAC have developed a novel approach for designing the external compression surface of the inlet that gives improved recovery and reduced sonic boom overpressures over conventional designs 8 . Inlets designed with this approach have been tested experimentally 9 and modeled computationally 10,11 , and shown to have good recovery and stability characteristics.…”

Section: Quiet Supersonic Jet (Qsj)mentioning

confidence: 99%

Coupled Analysis of an Inlet and Fan for a Quiet Supersonic Jet

Chima

Conners²,

Wayman³

2010

48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

Self Cite

View full text Add to dashboard Cite

Section: Quiet Supersonic Jet (Qsj)mentioning

confidence: 99%

Coupled Analysis of an Inlet and Fan for a Quiet Supersonic Jet

Chima

Conners²,

Wayman³

2010

48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

Self Cite

View full text Add to dashboard Cite

“…Both a single-stream concept (described herein) and a dual-stream concept (which employs a bypass stream around the turbofan) are being considered. Figure 1 compares a traditional axisymmetric design with a single-stream low-boom concept (6) . A key feature of the latter is the near-zero angle of the external cowl whereas the conventional cowl has a cross sectional area which increases in the streamwise direction leading to a finite external cowl angle (e.g.…”

Section: Cowl Angle and Compression Surfacementioning

confidence: 99%

“…The inlet must satisfy basic design principles used to decelerate the flow to subsonic speeds before entering the engine while also satisfying additional requirements for a quiet supersonic aircraft (4)(5)(6)(7)(8)(9)(10)(11)(12)(13) . The inlet design considered herein is based on a concept proposed by Conners and Howe (6) . As will be further discussed in the following sections of this paper, the inlet features a near-zero angle cowl that helps to minimise near-field sonic boom magnitude.…”

Section: Previous Studiesmentioning

confidence: 99%

Simulations of a low-boom, axisymmetric, external compression inlet

Coyne

Loth

Koncsek

et al. 2013

Aeronaut. j. (1968)

View full text Add to dashboard Cite

Computational simulations have been used to study a new low-boom, axisymmetric, external compression supersonic inlet with an on-design Mach number of 1·7. The inlet incorporates a relaxed compression surface with a near-zero cowl angle to help reduce external oblique shock waves due to spillage and cowl geometry. To reduce mechanical complexity the inlet is designed with zero-bleed. To understand the impact on performance and shock overpressure caused by the inlet itself, several throat and diffuser designs were simulated. The computations utilised a Reynolds-averaged Navier-Stokes code. Inflow properties were held consistent with the operational characteristics of the NASA GRC 8' × 6' Supersonic Wind Tunnel (SWT) for experimental testing of the inlet of Mach 1·67 at a Reynolds number of 5·4 × 10 6 . Stagnation pressure recovery performance for the baseline condition exceeded 94% at design mass flow rates, and reduced only slightly with increases in Mach number (consistent with theoretical predictions) and extension of cowl position. The simulations also showed that the relaxed compression surface combined with the near-zero cowl angle helps to significantly reduce external oblique shocks This is partly due to the reduced inlet spillage in combination with a reduced overall turning angle placed on the free-stream flow relative to the cowl shape.

show abstract

“…A low-boom external compression inlet design by Conners and Howe [12] of Gulfstream Aerospace Corporation is considered in the present work. The design features a zero-angle cowl and a relaxed isentropic compression centerbody spike, resulting in defocused oblique shock waves.…”

mentioning

confidence: 99%

Acoustically Induced Shock Oscillations in a Low-Boom Inlet

et al. 2016

View full text Add to dashboard Cite

Experimental unsteady centerbody surface pressures measured in a low-boom inlet have been analyzed and compared with an unsteady computational flow approach. The experimental dataset was gathered at the 8 × 6 ft supersonic wind tunnel at the NASA John H. Glenn Research Center in 2010. The axisymmetric external compression inlet considered herein featured a relaxed isentropic centerbody compression spike followed by a short subsonic diffuser to the aerodynamic interface plane. The axisymmetric inlet computational domain comprised a 10 deg sector, starting with the freestream inflow region, and included both the internal flowpath up to the mass flow plug and the external flow past the sharp-edged cowl for external flow. The selected inlet test conditions were based on a 1.67 freestream Mach number at a zero angle of attack with a near-design spillage rate of approximately 4%. Both experiments and simulations revealed temporal shifts between pressure peaks at different streamwise locations, indicating upstream-running compression waves that moved at acoustic speeds. These waves became amplified near the geometric throat and produced streamwise oscillations of the external normal shock. The simulations also revealed a second smaller shock on the centerbody at the geometric throat, for which the complex dynamics suggested an opportunity for further study. Nomenclature a = speed of sound D = diameter L = length N = number of unsteady pressure readings p = pressure r = radial direction coordinate t = time u = streamwise velocity component x = streamwise direction coordinate y = normal direction coordinate z = spanwise direction coordinate τ = timescale Subscripts AC = acoustic AIP = aerodynamic interface plane CB = centerbody cowl = inner cowl diff = averaged over low-speed diffuser end = wave end peak = local peak RMS = root mean square sh = shock start = wave start tip = spike tip ∞ = freestream condition Superscripts 0 = fluctuation = normalized

show abstract

Supersonic Inlet Shaping for Dramatic Reductions in Drag and Sonic Boom Strength

Cited by 33 publications

References 1 publication

Coupled Analysis of an Inlet and Fan for a Quiet Supersonic Jet

Coupled Analysis of an Inlet and Fan for a Quiet Supersonic Jet

Simulations of a low-boom, axisymmetric, external compression inlet

Acoustically Induced Shock Oscillations in a Low-Boom Inlet

Contact Info

Product

Resources

About