Calibration and validation of EASM turbulence model for jet flowfields

Papp, John; Kenzakowski, D. C.; Dash, S. M.

doi:10.2514/6.2002-855

Cited by 16 publications

(12 citation statements)

References 25 publications

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“…Launder & Sharma (1974) specifically calibrated the coefficients contained in the transport equations for K and ε for high Reynolds number jet flows and suggested the following values: c 1 = 1.43 and c 2 = 1.92. Furthermore, Papp et al (2002) recognized that the EASM α was calibrated for homogeneous turbulent wall-bounded flows, leading to an under-prediction of mixing rates in shear layers. They therefore made an attempt to recalibrate the EASM α for high Reynolds number jet flows and determined that an increase of a 1 from 0.4866 to 0.5416, in addition to using the coefficients by Launder & Sharma (1974), had the desired effect of increasing the turbulence levels in the shear layer without adversely affecting the pressure-strain rate correlation.…”

Section: Axisymmetric Rans Calculationsmentioning

confidence: 99%

“…and coefficients according to Papp et al (2002) (•), EASM α omitting c.e. and coefficients according to Papp et al (2002) ---), EASM α using c.e. and original coefficients (+), EASM α using c.e.…”

Section: Axisymmetric Rans Calculationsmentioning

confidence: 99%

“…and coefficients according to Papp et al (2002) (•), EASM α omitting c.e. and coefficients according to Papp et al (2002) ( ); Re D = 3, 300, 000, M = 2.46. both K and u v at the mean reattachment points and in the trailing wake. At the two latter locations, the STKE model considerably overpredicts the maxima of both K and u v .…”

Section: Axisymmetric Rans Calculationsmentioning

confidence: 99%

“…Launder et al (1975), for comparison. In addition, the applicability of compressibility extensions, coefficient modifications as suggested by Papp et al (2002), and the influence of the inflow conditions on the global solution are investigated. Finally, both the RANS and the novel FSM approach are applied to the UIUC case.…”

mentioning

confidence: 99%

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Simulation of Supersonic Base Flows: Numerical Investigations Using DNS, LES, and URANS

Fasel¹,

Sandberg²

2006

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Public Reporting Burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comment regarding this burden estimate or any other aspect of this collection of information, including suggesstions for reducing this burden, Simulation of Supersonic Base Flows: Numerical Investigations Using DNS, LES, and URANS Report Title ABSTRACTTransitional and turbulent supersonic axisymmetric wakes were investigated by conducting various numerical experiments. The main objective was to identify hydrodynamic instability mechanisms in the flow at Mach number M = 2.46 for several Reynolds numbers, and relating these to coherent structures that are found from various visualization techniques. The premise for this approach is the assumption that flow instabilities lead to the formation of coherent structures. The effect of these structures on the mean flow is of particular interest, as they strongly affect the base drag. Three high-order accurate compressible codes were developed in cylindrical coordinates for this research: A spatial Navier-Stokes (N-S) code to conduct Direct Numerical Simulations (DNS), a linearized N-S code for linear stability investigations using two-dimensional basic states, and a temporal N-S code for performing local stability analyses. The ability of numerical simulations to deliberately exclude physical effects is exploited. This includes intentionally eliminating certain azimuthal/helical modes by employing DNS for various circumferential domain-sizes. With this approach, the impact of structures associated with certain modes on the global wake-behavior can be scrutinized. It is concluded that azimuthal modes with low wavenumbers are responsible for a flat mean base-pressure distribution and that k=2 and k=4 are the dominant modes in the trailing wake, producing a four-lobe wake pattern. Complementary spatial and temporal calculations are carried out to investigate whether instabilities are of local or global nature. Circumstatial evidence is presented that absolutely unstable global modes within the recirculation region coexist with convectively unstable shear-layer modes. The flow is found to be absolutely unstable with respect to modes k>0 for Re_D > 5,000 and with respect to the axisymmetric mode for Re_D>100,000. Furthermore, it is investigated whether flow control measures designed to weaken the naturally most significant modes can decrease the base drag. Finally, the novel Flow Simulation Methodology (FSM), using state-of-the-art turbulence closures, was shown to reproduce DNS results at a fraction of the computational cost.

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Section: Axisymmetric Rans Calculationsmentioning

confidence: 99%

Section: Axisymmetric Rans Calculationsmentioning

confidence: 99%

Section: Axisymmetric Rans Calculationsmentioning

confidence: 99%

mentioning

confidence: 99%

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Simulation of Supersonic Base Flows: Numerical Investigations Using DNS, LES, and URANS

Fasel¹,

Sandberg²

2006

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“…While we have incorporated scalar fluctuation equations [9] and a variable Prandtl number model [10] in our CFD codes, these have not been extended to account for compressibility effects which serve to diminish scalar fluctuation levels. Our work with more advanced explicit algebraic stress models (EASM) for jet noise applications [11,12] is still at the research stage and the subject of current investigation in a NASA Glenn program. Table 1.…”

Section: Introductionmentioning

confidence: 99%

CFD Support for Jet Noise Reduction Concept Design and Evaluation for F/A 18 E/F Aircraft

Dash¹,

Kenzakowski²,

Kannepalli³

2003

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CFD is being used to support the design and evaluation of varied passive concepts which have the potential to reduce jet noise on an F/A 18 E/F supersonic fighter aircraft. One aspect of the CFD support work entails basic concept evaluation which is being performed in collaboration with laboratory studies of Krothapalli at FSU and Seiner at NCPA/U.Miss. Concepts evaluated to date include microjets, chevrons and hybrid devices. CFD is supporting the optimization of these designs and evaluating how they will perform on a real engine. A new jet noise code is being evaluated which has the promise of quantifying the noise reduction obtainable. A major role is that of ascertaining the effect of plume/plume interactions as well as installation /aerodynamic effects which requires a very detailed, CPU intensive studies. Improvements to the CFD in the areas of RANS turbulence modeling are improving overall accuracy, while efficiency upgrades have been achieved via use of adaptive gridding on massively parallel architectures, as well as by use of new parabolized approximations.

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Navier–Stokes analysis methods for turbulent jet flows with application to aircraft exhaust nozzles

Georgiadis¹,

DeBonis²

2006

Progress in Aerospace Sciences

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Calibration and validation of EASM turbulence model for jet flowfields

Cited by 16 publications

References 25 publications

Simulation of Supersonic Base Flows: Numerical Investigations Using DNS, LES, and URANS

Simulation of Supersonic Base Flows: Numerical Investigations Using DNS, LES, and URANS

CFD Support for Jet Noise Reduction Concept Design and Evaluation for F/A 18 E/F Aircraft

Navier–Stokes analysis methods for turbulent jet flows with application to aircraft exhaust nozzles

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